Clinical Aspects, Diagnosis and Therapy of Canine Pyoderma
D.N. Carlotti, DECVD
Cabinet de Dermatologie Vétérinaire
Bordeaux-Mérignac, France
Introduction
There are a large number of bacterial diseases of the skin in dogs, with different histopathological and clinical aspects. Some are superficial and benign (the basement membrane is not destroyed by the infectious process) and some are deep and severe (the basement membrane is destroyed). Pseudopyodermas are not real pyodermas since infection plays only a secondary role and anti-infectious therapy is not effective. Staphylococcus intermedius is the most common infectious agent cultured in canine pyoderma. It can multiply easily in the dog's skin, due to the thinness of the stratum corneum and the lack of sebum plug in the hair follicles. Inflammation of the skin, particularly due to allergy, is the most common cause of pyoderma, more than real immunodeficiency.
Superficial pyoderma
1. Skin fold pyoderma (intertrigo)
These lesions are seen in anatomical defects where there is an important bacterial colonization: lip, facial, vulvar, caudal, obese and mammary folds. The dermatosis is localized with erythema, exudation, suppuration and bad odour.
2. Impetigo
In juvenile impetigo, subcorneal pustules are present on the ventral side of the body, with crusting. The disease is self-limited. In adult impetigo, large pustules ("bullae") are seen all over the body. In general, adult impetigo is severe and secondary to an underlying disease (hyperadrenocorticism, glucocorticoid therapy...) or multiple traumas (e.g., during hunting).
3. Folliculitis
Juvenile folliculitis: numerous follicular pustules are present on the ventral side of the body. The condition often heals at puberty.
Short-haired dog pyoderma: there are generalized follicular pustules, epidermal collarettes and crusts, with a "moth-eaten" hair. Pruritus disappears when the lesion heal.
Secondary folliculitis: this common disease is characterized by follicular pustules, epidermal collarettes and crusts which are often generalized. Pruritus is still present after lesions healing in case of underlying pruritic dermatosis. The disease may also generate pruritus in a usually nonpruritic dermatosis (in such cases pruritus disappears when lesions heal).
"Bacterial hypersensitivity" and/or superficial spreading pyoderma: bacterial hypersensitivity is an uncommon disease based on a clinical triad: erythematous follicular pustules, target lesions/seborrhoeic plaques, haemorrhagic bullae. There is sometimes a severe pruritus. The existence of a real bacterial allergy is presumed and debatable. In superficial spreading pyoderma, nummular areas of alopecia and erythema are centrifugally expanding, with epidermal collarettes and crusts. These lesions are often associated to intact but transient follicular pustules.
Deep folliculitis: it is the so-called acral lick dermatitis, most often a deep follicular bacterial infection with retrograde hidrosadenitis secondary to a psychogenic and/or an allergic cause.
Pyotraumatic folliculitis: some cases of folliculitis (e.g., in Labradors, Retrievers) appear as oozing suppurative plaque with pain. They are surrounded by satellite pustules of folliculitis or even furunculosis, which help to differentiate them from the "classical" pyotraumatic dermatitis.
Deep pyoderma
1 Furunculosis
Acne: papulo-pustules and pustules are seen on the face, particularly the chin, in young dogs.
Secondary furunculosis: localized or generalized pustules are associated or secondary to a folliculitis and the disease is triggered or aggravated by an excessive therapy (e.g., glucocorticosteroids).
Nasal pyoderma: pustules and crusts are present on the bridge of the nose and eyelids. There may be an unpleasant scaring. This true bacterial nasal pyoderma of unknown cause should be differentiated from the sterile eosinophilic furunculosis possibly due to arthropod bites.
2. Cellulitis
A. Localized cellulitis
Pressure points pyoderma: there are necrotizing lesions of the elbows, the rump, the stifles, the hocks and the lateral digits. They are due to permanent trauma in heavy dogs.
Various localized cellulites: These are other localized necrotizing lesions (e.g., perianal). Their cause is often unknown; they are sometimes secondary to a furunculosis.
B. Generalized cellulitis
Pyodemodicosis: There is an extensive necrotizing skin disease, which is secondary to a generalized demodicosis (an immunodeficiency status).
Various generalized cellulites: necrotizing lesions are extensive and often secondary to other immunodeficiencies.
3. The interdigital pyoderma complex
There are very numerous causes of non infectious pododermatitis with erythema, oedema, oozing and alopecia. The same lesions are present in interdigital pyoderma along with furunculosis, ulcerations, fistulae and necrosis (cellulitis). Interdigital pyoderma is often secondary.
Pseudo-pyoderma
1. Pyotraumatic dermatitis
The typical lesions have an acute onset and are characterized by alopecia, erythema, oozing, suppuration, pruritus and/or pain. These lesions are common, and most often associated to pruritic skin disease. They are poorly understood (sometimes due to vasculitis?). There is a spontaneous healing in a few days, but a short treatment is useful.
2. Juvenile pyodermas
Juvenile pyoderma of new-born puppies: crusty lesions are present on the face, thorax and dorso-lumbar area. They might be due to trauma. No treatment is required since there is a spontaneous healing.
Juvenile cellulitis: The aetiology of this disease is unknown. The typical clinical aspect is a facial oedema and furunculosis, with fistulae, crusting and a suppurative otitis externa. Adenopathy and sterile abscesses (cellulitis) are present. The onset of this uncommon disease occurs before 4 months of age in one or several puppies of a litter. There is a spontaneous healing in a few weeks with scaring but treatment is required.
Diagnosis of canine pyoderma
Diagnosis of canine pyoderma is based on history, physical examination and complementary examinations: cytology, histopathology and bacteriology.
1. Cytology
In intertrigo (skin fold pyoderma), images of "bacterial colonization" are observed, i.e., healthy neutrophils, Cocci and Bacilli in an extracellular position and degenerated neutrophils in a state of phagocytosis. In impetigo and folliculitis, impaired (degenerated) neutrophils are only found. The pictures of Cocci phagocytosis are not particularly numerous. This is an image of "bacterial invasion", i.e., the penetration of pathogenic germs into the skin. The significance of the pictures of phagocytosis differs considerably depending on whether they are observed on the surface or in a cutaneous lesion. In effect, when they are observed inside the skin (epidermis, hair follicles, dermis) one might consider that the phagocytosed germs are pathogenic and that there is a real bacterial pustulosis. In contrast, phagocytosis observed on the surface indicates multiplication of germs which are not necessarily and probably rarely pathogenic. In deep pyoderma cytology is less likely to reveal the germs and pictures of phagocytosis, although they must be looked for. Frequently there are a granulomatous reaction, eosinophils and red blood cells. Bacterial colonization is observed in pyotraumatic dermatitis as in intertrigo but it is not significant and treatment with antibiotic does not result in remission. In juvenile cellulitis, the degenerated neutrophils are very numerous, with a granulomatous reaction. No germs are seen.
2. Histopathology
This will show typical lesions, but is relatively rarely performed for the diagnosis of canine pyoderma, except in case of difficult differential diagnosis.
3. Bacteriology
This can confirm the bacterial infection and allows sensitivity testing.
Treatment of canine pyoderma
Systemic (antibiotic) and topical therapy can be used in canine pyoderma.
1. Selection of antibiotics
The criteria for the choice of an antibiotic are as follows: appropriate kinetics and good cutaneous penetration, activity against Staphylococci, activity in pus and reactive tissues, bactericidal activity rather than bacteriostatic activity particularly in severe cases, easy administration (oral, q12h or q24h), absence of secondary effects, reasonable cost. The choice can be empirical, particularly in superficial pyoderma, after cytological examination of pus from an intact pustule which shows bacterial invasion. Bacteriology and sensitivity testing must be used in case of deep pyoderma, recurrent pyoderma, when cytology shows a complex flora with rods, and in case of empirical antibiotic therapy failure. They can be repeated during therapy.
2. Dosage and duration of treatment
Ideal doses must be used and duration of treatment must be long enough (a few weeks to several months depending of extension and depth of lesions, and always beyond clinical cure). Maintenance pulse treatment (e.g., 2 to 3 days a week) can be used in chronically relapsing pyoderma but it could theoretically select resistant strains as well as the use of subminimal doses. They are both used for economical reasons but the former is preferable.
3. Antibiotics useable in canine pyoderma
Antibiotics useful in canine pyoderma are included in the following table. They all have a good cutaneous diffusion (because of their liposolubility) and can be given orally, which is useful because of long therapeutic courses (ease of administration). They are all bactericidal except macrolides which are bacteriostatic.
Class
Characteristics
Examples
Macrolides
narrow spectrum/Gram+
erythromycin : 30 to 50 mg/kg div. bid or tid
lincomycin : 40 to 50 mg/kg div. bid or tid
clindamycin : 5,5 to 11 mg/kg sid or div. Bid
tylosin : 40 mg/kg div. bid
Penicillins M
resistant to penicillinases
narrow spectrum/Gram+
oxacillin : 30 to 50 mg/kg div. bid
Penicillins A
potentiated by
clavulanic acid
resistant to penicillinases larger spectrum
amoxicillin-clavulanic acid : 25 mg/kg/div. bid
Cephalosporins
resistant to penicillinases
broad spectrum
cephalexin : 30 to 60 mg/kg div. Bid
cefadroxil : 44 to 70 mg/kg div. bid
Cephalosporin P
resistant to penicillinases
narrow spectrum/Gram+
synergy with penicillins
and erythromycin
fusidic acid (the only one of this group) :
60 mg/kg div. tid
Sulfonamides-
Diaminopyrimidines
broad spectrum
trimethoprim-sulfa : 30 mg (i.e., 5 mg
trimethoprim)/kg sid or div. Bid
baquiloprim-sulfadimethoxine : 30 mg (i.e., 5mg
baquiloprim)/kg q.48h
ormetoprim-sulfadimethoxine : 30 mg (i.e., 5mg
ormetoprim)/kg sid after a single double dose
the first day
Fluoroquinolones
broad spectrum
excellent tissue
penetration
(not to be used in puppies of giant breeds)
enrofloxacin : 5mg/kg sid of div. Bid
marbofloxacin : 2 mg/kg sid
difloxacin : 5 mg/kg sid
orbifloxacin : 2.5 mg/kg sid
Penicillin G (which is injectable) and A are sensitive to penicillinases. Aminoglycosides have a low cutaneous diffusion (they are hydrosoluble), are injectable and toxic. Chloramphenicol has a bad reputation in humans and the cat (haematologic toxicity). Tetracyclines have a very low activity against Staphylococci. These antibiotics are never or rarely used in canine pyoderma. Rifampicin is effective against Staphylococci but, as it is still used to treat human tuberculosis, it should be used when there is no other possibility (5 to 10 mg/kg SID). In addition, it should be then associated to a betalactamine to prevent the selection of resistant strains of Staphylococci. Mupirocine, a topically active bactericidal antibiotic, in a polyethylene glycol base is effective against Gram+ Cocci, is not systematically absorbed and is not chemically related to other antibiotics. It can be used in localized pyodermas (acne, pressure point pyoderma, interdigital pyoderma).
4. Associated treatments
Topical therapy is always beneficial in canine pyoderma, particularly in superficial staphylococcal disease. Clipping can be useful and is necessary in deep pyoderma such as cellulitis. The main useful topical products are chlorhexidine (lotion and/or shampoo), povidone-iodine (lotion and/or shampoo), benzoyl-peroxide (shampoo and eventually gel), ethyl-lactate (shampoo). They should be used frequently, e.g., once a day, at the beginning of therapy. Later, frequency of application may decrease. Each shampoo should be followed by the application of an appropriate humectant. Topical or systemic glucocorticoids should never be used in true canine pyoderma, even in case of pruritus, because they cause severe relapses ("rebound effect"). In contrast they can be used and are effective in pseudo-pyoderma (e.g., oral prednisolone: 1 mg/kg/day for pyotraumatic dermatitis and 2 mg/kg/day for juvenile cellulitis).
Conclusion
Canine pyoderma is a group of various skin diseases and an accurate diagnosis is mandatory. An appropriate antibacterial therapy is required in most cases of canine pyoderma, in association with topical therapy. Antibiotics must be selected carefully and used with appropriate dosage and duration of treatment.
Showing posts with label Pyoderma. Show all posts
Showing posts with label Pyoderma. Show all posts
Tuesday, November 4, 2008
The Efficacy of Ibafloxacin Tablets and Gel in the Treatment of Canine Pyoderma
The Efficacy of Ibafloxacin Tablets and Gel in the Treatment of Canine Pyoderma
*L. J. I. Horspool, R. van den Bos, P. van Laar
*Intervet International bv
Boxmeer, NL
Linda.Horspool@intervet.com
OBJECTIVES
Canine pyoderma is an inflammatory skin disease that is commonly encountered in clinical practice. Staphylococcus intermedius is the primary cause of pyoderma in dogs. However a number of underlying causes (such as seborrhea, parasites, immune incompetence (corticosteroid use), endocrine imbalance) can predispose to the development of canine pyoderma.
In the present study, the efficacy of the tablet formulation of the novel fluoroquinolone ibafloxacin was compared with a new gel formulation containing ibafloxacin in a multicentre, randomised, non-blinded, controlled clinical study on canine pyoderma in The Netherlands, Germany and Italy.
MATERIALS
Dogs with pyoderma were administered ibafloxacin (Ibaflin®, Intervet International bv) orally, at a dose rate of 15 mg/kg bodyweight, as tablets (Group 1, n=94) or gel (Group 2, n=93) for 21-91 days. Clinical examinations were carried out on Days 0, 7 and 21 and then every 14 days until treatment was stopped. Bacterial culture was performed on Day 0. The response to treatment was evaluated using the number of treatment failures (lack of improvement by Day 7 or 21) and the improvement in general condition and pyoderma lesion scores. The overall response to treatment was based on clinical examinations 7 and 28 days after treatment was stopped.
RESULTS
Staphylococcus intermedius was cultured from 82% of Group 1 and 88% of Group 2. The pyoderma was considered to be superficial in 58% and deep in 42% of the dogs in the present study. The mean duration of treatment was 5-6 weeks in both groups. The number of treatment failures and the improvement in general condition or specific disease scores did not differ significantly between the two groups. Seven days after the last treatment, 80% of Group 1 and 84% of Group 2 were classed as having responded to treatment (P>0.05). Mild suspected adverse reactions to treatment (dullness, polydipsia) were reported for 2 dogs in Group 1 (2.1%) and 1 dog in Group 2 ((1.1%).
CONCLUSION
The present study was designed so that all dogs would be treated for at least 3 weeks (suitable for superficial pyoderma). Deep pyoderma requires longer treatment (at least 6 weeks) and is more difficult to manage, thus dogs in the present study could be treated for up to 13 weeks. Fluoroquinolones have a broad spectrum of activity, are widely distributed in the body and can be administered orally once daily, making them ideal for the treatment of canine pyoderma. In the present study, ibafloxacin was equally effective in the treatment of canine pyoderma when formulated as conventional tablets or as gel for oral administration. In addition, suspected adverse reactions to treatment with ibafloxacin tablets or gel occurred at a similar low rate even during prolonged treatment.
*L. J. I. Horspool, R. van den Bos, P. van Laar
*Intervet International bv
Boxmeer, NL
Linda.Horspool@intervet.com
OBJECTIVES
Canine pyoderma is an inflammatory skin disease that is commonly encountered in clinical practice. Staphylococcus intermedius is the primary cause of pyoderma in dogs. However a number of underlying causes (such as seborrhea, parasites, immune incompetence (corticosteroid use), endocrine imbalance) can predispose to the development of canine pyoderma.
In the present study, the efficacy of the tablet formulation of the novel fluoroquinolone ibafloxacin was compared with a new gel formulation containing ibafloxacin in a multicentre, randomised, non-blinded, controlled clinical study on canine pyoderma in The Netherlands, Germany and Italy.
MATERIALS
Dogs with pyoderma were administered ibafloxacin (Ibaflin®, Intervet International bv) orally, at a dose rate of 15 mg/kg bodyweight, as tablets (Group 1, n=94) or gel (Group 2, n=93) for 21-91 days. Clinical examinations were carried out on Days 0, 7 and 21 and then every 14 days until treatment was stopped. Bacterial culture was performed on Day 0. The response to treatment was evaluated using the number of treatment failures (lack of improvement by Day 7 or 21) and the improvement in general condition and pyoderma lesion scores. The overall response to treatment was based on clinical examinations 7 and 28 days after treatment was stopped.
RESULTS
Staphylococcus intermedius was cultured from 82% of Group 1 and 88% of Group 2. The pyoderma was considered to be superficial in 58% and deep in 42% of the dogs in the present study. The mean duration of treatment was 5-6 weeks in both groups. The number of treatment failures and the improvement in general condition or specific disease scores did not differ significantly between the two groups. Seven days after the last treatment, 80% of Group 1 and 84% of Group 2 were classed as having responded to treatment (P>0.05). Mild suspected adverse reactions to treatment (dullness, polydipsia) were reported for 2 dogs in Group 1 (2.1%) and 1 dog in Group 2 ((1.1%).
CONCLUSION
The present study was designed so that all dogs would be treated for at least 3 weeks (suitable for superficial pyoderma). Deep pyoderma requires longer treatment (at least 6 weeks) and is more difficult to manage, thus dogs in the present study could be treated for up to 13 weeks. Fluoroquinolones have a broad spectrum of activity, are widely distributed in the body and can be administered orally once daily, making them ideal for the treatment of canine pyoderma. In the present study, ibafloxacin was equally effective in the treatment of canine pyoderma when formulated as conventional tablets or as gel for oral administration. In addition, suspected adverse reactions to treatment with ibafloxacin tablets or gel occurred at a similar low rate even during prolonged treatment.
The Approach to Canine Recurrent Pyoderma
The Approach to Canine Recurrent Pyoderma
Richard EW Halliwell, MA VetMB PhD MRCVS DECVD
Professor, University of Edinburgh, Royal (Dick) School of Veterinary Studies, Summerhall
Edinburgh, UK
THE DEVELOPMENT OF PYODERMA
It is believed that staphylococcal pyoderma develops following surface spread from the carrier sites. Factors that ordinarily prevent the development of pyoderma are:
1. The physical barrier of the intact skin. Normal desquamation is extremely important in preventing niches in which pathogenic bacteria could become established.
2. Antibacterial substances present in normal sebum, and secreted onto the skin surface from apocrine secretions. This would include immunoglobulin, and other non-specifically acting substances such as those produced by resident bacteria.
3. The bacterial barrier. If non-pathogenic bacteria occupy all available colonization sites, pathogens will not become established.
There is thus a dynamic balance between the host defenses, the virulence of any potential pathogens and their ability to gain access, and the host defenses that are brought into play in a damage limitation exercise.
FACTORS THAT PREDISPOSE TO RECURRENT PYODERMAS
Pyoderma is likely to prove recurrent in a number of situations
1. Where there is a tendency to surface colonization:
a. Seborrhoea, of whatever cause, is likely to lead to colonization with Staph intermedius.
b. Atopic disease. In this condition it has been shown that Stratum corneum cells of atopics have a greater tendency to adhere to the organism than do cells from normals.
2. Where the integrity of the skin barrier is impaired:This may occur secondarily to any inflammatory skin disease, or one that leads to self-trauma from pruritus. Flea allergy is a rather special case. The secondary infection in such cases is often minor, and does not necessitate antibiotic therapy. However a minority of animals will break with a staphylococcal infection whenever they acquire an infestation. In demodicosis, a recurrence of the infection is often the first sign of recurrence of the mite population.
3. In the immunocompromised animal: This is generally limited to deficiencies in non-specific defenses or in cell-mediated immunity, as antibody response is always evident.
a. Congenital non-specific immune defects. Delayed intracellular killing by neutrophils has been noted in weimaraners and dobermans. Irish setters have been reported with a severe, intracellular killing defect, but this is exceedingly rare. However, absence of the neutrophil complement receptors CD11b and CD18, which aid attachment prior to engulfment, is quite common in Irish setters in the UK and Scandinavia. Such animals would be expected to have difficulties in handling infections of all types.
b. Impaired cell-mediated immunity. It has been documented that atopic dogs have impaired cell-mediated immunity. In animals with impaired cell-mediated immunity from other causes has also been documented. Some animals with recurrent pyoderma have impaired cell-mediated immunity- where their lymphocytes appear to have an inbuilt defect, or where there are serum immunosuppressive factors present. This seems to be an excellent way by which the infection can be potentiated.
4. Food allergy:Typically, affected animals are less pruritic when on antibiotics with their pyoderma controlled, but relapse occurs either immediately on cessation of therapy or within 2-3 weeks. In other cases the pruritus is fully controlled by antibiotic therapy, and the animal appears to be suffering from a food allergy which is sub clinical as far as the pruritus is concerned.
5. In cases of hypersensitivity to staphylococcal antigens:It is well documented in experimental animals that development of hypersensitivity renders the animal much easier to infect. This has been shown also to be true in dogs.
6. Hypothyroidism:This is well recognized as a cause of recurrent staphylococcal infection, but it is not clear whether it results from the accompanying seborrhea, or to impaired defenses that may accompany the condition.
7. Iatrogenic:
a. Improper use of antibiotics. These must be given in full doses for the full length of time.
b. Use of corticosteroids. Although these may appear to produce an improvement, merely from their anti-inflammatory action, in the long term they are working against our best interests as they (a), tend to dry the skin inducing scaling and thus favoring colonization, and (b), they may further impair cell-mediated immunity.
Antibiotic selection
Suitable antibiotics are directed at the Staph. intermedius. Where there is secondary infection with gram-negatives, these will disappear once the Staph. is controlled unless the animal is severely immunodeficient, or there is an overwhelming infection.
1. Macrolides.Erythromycin and lincomycin are good, first choice bacteriostatic antibiotics. Clindamycin does not appear to offer any major advantages over the other, cheaper, products. The vomiting with erythromycin can be obviated by feeding an anti-emetic 30 minutes prior to each dose for the first two days. There is cross-resistance between the two drugs. The dose for erythromycin is 10-15mg/kg TID, and for lincomycin 20mg/kg BID.
2. Potentiated sulphonamides. Trimethoprim-sulphadiazine (or sulphamethoxazole), ormetoprim-sulphadimethoxine and bacquiloprim-sulphadimethoxine are very useful antibiotics for pyodermas. The dose for the first is 30mg/kg given twice daily, although some clinicians are comfortable with SID dosage. The dose for ormetoprim is 55mg/kg for the first day, and then 27.5mg/kg once daily thereafter. Drug reactions are not uncommon with trimethoprim sulphur, and result from the sulphadiazine, which also has the propensity to induce a transient arthropathy, especially in Dobermans. The tendency to induce keratoconjunctivitis sicca must be watched.
3. Cephalosporins. Cephadroxyl and cephalexin are excellent for the treatment of pyodermas. Although they are broader spectrum than is oxacillin, they do not classify as broad-spectrum drugs, and are perfectly acceptable for the routine treatment of canine pyoderma. Drug reactions are seen, but probably with less frequency than with the sulphonamides. They are bactericidal. Doses are 20-25mg/kg BID.
4. Oxacillin. This is an excellent, narrow spectrum bactericidal antibiotic to which resistance is extremely rare. Unfortunately there are no veterinary preparations. The dose is 20mg/kg TID.
5. Amoxacillin/clavulonic acid. This broad-spectrum bactericidal antibiotic is very useful. Doses used range from 15-20mg/kg BID.
6. Fluoroquinolones. These are very broad spectrum, bactericidal antibiotics. It would be indicated where there is a significant involvement of gram negatives. Recommended doses are 2.5mg/kg BID (or 5mg SID) for enrofloxacin, 2.0mg/kg SID for marbofloxacin. 2.5mg/kg SID for orbofloxacin and 5-10 mg/kg BID for difloxacin. They are, however, not indicated for routine use in dermatology, due to the possibility of inducing resistance in Pseudomonas.
Topical therapy
Antibacterial shampoos using products containing benzoyl peroxide (2-3%), clorhexidene (2-4%) or ethyl lactate (10%) form a most valuable supplementary treatment. Chitosanide, which is contained in the new spherulite-based shampoos of Virbac, also has antibacterial properties. Shampoos can be used 1-2 times weekly therapeutically, and are also useful as part of a preventative maintenance strategy.
In the case of deep pyodermas, antibacterial soaks employing povidone iodine are a valuable aid, and can be done twice weekly in the initial stages of treatment. In the case of localised deep pyodermas, benzoyl peroxide gels are of value. Also, where there is evidence of ingrown hairs forming foreign body reactions, these should be gently massaged out in warm water soaks.
THE APPROACH TO THE RECURRENT INFECTION
1. Search for a predisposing cause.
a. Evaluate for seborrhea. If this is evident, look for a cause of the seborrhea.
b. Evaluate for evidence of ectoparasitic disease. Be sure to search repeatedly for demodex in any case of recurrent deep pyoderma, particularly pododermatitis. Biopsies are sometimes necessary to demonstrate mites in such cases.
c. Check for thyroid function, even in animals that are not overtly seborrheic.
d. Skin test, or undertake in vitro tests for atopy, even if animals are not pruritic when their pyoderma is controlled.
e. Do an elimination diet for food allergy, again, even if the animal is not pruritic when the pyoderma is controlled.
f. Unfortunately, work-up for immunological defects is not generally available, but should be pursued if possible if all of the above are negative.
2. Therapy for the recurrent case with no apparent cause.
a. Be sure to use the appropriate antibiotic therapy supported by results of in vitro sensitivity tests. Bactericidal therapy is preferred in recurrent cases.
b. Use good supporting antibacterial shampoos. These may be alternated with antiseborrhoeic shampoos if seborrhoea is evident.
c. Consider using immunotherapy with a staphylococcal product e.g., Staph Phage Lysate (Delmont Labs, Swarthmore, PA, USA).
d. As a last resort some clinicians advocate:
i. Continued antibiotic therapy in normal doses,
ii. Intermittent full courses at full dosage with one month on and one month off.
iii. Intermittent full dose therapy on, say, two consecutive days each week.
iv. Continual low dose therapy, which seems conceptually the least desirable approach.
Speaker Information
(click the speaker's name to view other papers and abstracts submitted by this speaker)
Richard EW Halliwell, MA, VetMB, PhD, MRCVS, DECVD
Professor, University of Edinburgh, Royal (Dick) School of Veterinary Studies, Summerhall
Edinburgh, UK
Richard EW Halliwell, MA VetMB PhD MRCVS DECVD
Professor, University of Edinburgh, Royal (Dick) School of Veterinary Studies, Summerhall
Edinburgh, UK
THE DEVELOPMENT OF PYODERMA
It is believed that staphylococcal pyoderma develops following surface spread from the carrier sites. Factors that ordinarily prevent the development of pyoderma are:
1. The physical barrier of the intact skin. Normal desquamation is extremely important in preventing niches in which pathogenic bacteria could become established.
2. Antibacterial substances present in normal sebum, and secreted onto the skin surface from apocrine secretions. This would include immunoglobulin, and other non-specifically acting substances such as those produced by resident bacteria.
3. The bacterial barrier. If non-pathogenic bacteria occupy all available colonization sites, pathogens will not become established.
There is thus a dynamic balance between the host defenses, the virulence of any potential pathogens and their ability to gain access, and the host defenses that are brought into play in a damage limitation exercise.
FACTORS THAT PREDISPOSE TO RECURRENT PYODERMAS
Pyoderma is likely to prove recurrent in a number of situations
1. Where there is a tendency to surface colonization:
a. Seborrhoea, of whatever cause, is likely to lead to colonization with Staph intermedius.
b. Atopic disease. In this condition it has been shown that Stratum corneum cells of atopics have a greater tendency to adhere to the organism than do cells from normals.
2. Where the integrity of the skin barrier is impaired:This may occur secondarily to any inflammatory skin disease, or one that leads to self-trauma from pruritus. Flea allergy is a rather special case. The secondary infection in such cases is often minor, and does not necessitate antibiotic therapy. However a minority of animals will break with a staphylococcal infection whenever they acquire an infestation. In demodicosis, a recurrence of the infection is often the first sign of recurrence of the mite population.
3. In the immunocompromised animal: This is generally limited to deficiencies in non-specific defenses or in cell-mediated immunity, as antibody response is always evident.
a. Congenital non-specific immune defects. Delayed intracellular killing by neutrophils has been noted in weimaraners and dobermans. Irish setters have been reported with a severe, intracellular killing defect, but this is exceedingly rare. However, absence of the neutrophil complement receptors CD11b and CD18, which aid attachment prior to engulfment, is quite common in Irish setters in the UK and Scandinavia. Such animals would be expected to have difficulties in handling infections of all types.
b. Impaired cell-mediated immunity. It has been documented that atopic dogs have impaired cell-mediated immunity. In animals with impaired cell-mediated immunity from other causes has also been documented. Some animals with recurrent pyoderma have impaired cell-mediated immunity- where their lymphocytes appear to have an inbuilt defect, or where there are serum immunosuppressive factors present. This seems to be an excellent way by which the infection can be potentiated.
4. Food allergy:Typically, affected animals are less pruritic when on antibiotics with their pyoderma controlled, but relapse occurs either immediately on cessation of therapy or within 2-3 weeks. In other cases the pruritus is fully controlled by antibiotic therapy, and the animal appears to be suffering from a food allergy which is sub clinical as far as the pruritus is concerned.
5. In cases of hypersensitivity to staphylococcal antigens:It is well documented in experimental animals that development of hypersensitivity renders the animal much easier to infect. This has been shown also to be true in dogs.
6. Hypothyroidism:This is well recognized as a cause of recurrent staphylococcal infection, but it is not clear whether it results from the accompanying seborrhea, or to impaired defenses that may accompany the condition.
7. Iatrogenic:
a. Improper use of antibiotics. These must be given in full doses for the full length of time.
b. Use of corticosteroids. Although these may appear to produce an improvement, merely from their anti-inflammatory action, in the long term they are working against our best interests as they (a), tend to dry the skin inducing scaling and thus favoring colonization, and (b), they may further impair cell-mediated immunity.
Antibiotic selection
Suitable antibiotics are directed at the Staph. intermedius. Where there is secondary infection with gram-negatives, these will disappear once the Staph. is controlled unless the animal is severely immunodeficient, or there is an overwhelming infection.
1. Macrolides.Erythromycin and lincomycin are good, first choice bacteriostatic antibiotics. Clindamycin does not appear to offer any major advantages over the other, cheaper, products. The vomiting with erythromycin can be obviated by feeding an anti-emetic 30 minutes prior to each dose for the first two days. There is cross-resistance between the two drugs. The dose for erythromycin is 10-15mg/kg TID, and for lincomycin 20mg/kg BID.
2. Potentiated sulphonamides. Trimethoprim-sulphadiazine (or sulphamethoxazole), ormetoprim-sulphadimethoxine and bacquiloprim-sulphadimethoxine are very useful antibiotics for pyodermas. The dose for the first is 30mg/kg given twice daily, although some clinicians are comfortable with SID dosage. The dose for ormetoprim is 55mg/kg for the first day, and then 27.5mg/kg once daily thereafter. Drug reactions are not uncommon with trimethoprim sulphur, and result from the sulphadiazine, which also has the propensity to induce a transient arthropathy, especially in Dobermans. The tendency to induce keratoconjunctivitis sicca must be watched.
3. Cephalosporins. Cephadroxyl and cephalexin are excellent for the treatment of pyodermas. Although they are broader spectrum than is oxacillin, they do not classify as broad-spectrum drugs, and are perfectly acceptable for the routine treatment of canine pyoderma. Drug reactions are seen, but probably with less frequency than with the sulphonamides. They are bactericidal. Doses are 20-25mg/kg BID.
4. Oxacillin. This is an excellent, narrow spectrum bactericidal antibiotic to which resistance is extremely rare. Unfortunately there are no veterinary preparations. The dose is 20mg/kg TID.
5. Amoxacillin/clavulonic acid. This broad-spectrum bactericidal antibiotic is very useful. Doses used range from 15-20mg/kg BID.
6. Fluoroquinolones. These are very broad spectrum, bactericidal antibiotics. It would be indicated where there is a significant involvement of gram negatives. Recommended doses are 2.5mg/kg BID (or 5mg SID) for enrofloxacin, 2.0mg/kg SID for marbofloxacin. 2.5mg/kg SID for orbofloxacin and 5-10 mg/kg BID for difloxacin. They are, however, not indicated for routine use in dermatology, due to the possibility of inducing resistance in Pseudomonas.
Topical therapy
Antibacterial shampoos using products containing benzoyl peroxide (2-3%), clorhexidene (2-4%) or ethyl lactate (10%) form a most valuable supplementary treatment. Chitosanide, which is contained in the new spherulite-based shampoos of Virbac, also has antibacterial properties. Shampoos can be used 1-2 times weekly therapeutically, and are also useful as part of a preventative maintenance strategy.
In the case of deep pyodermas, antibacterial soaks employing povidone iodine are a valuable aid, and can be done twice weekly in the initial stages of treatment. In the case of localised deep pyodermas, benzoyl peroxide gels are of value. Also, where there is evidence of ingrown hairs forming foreign body reactions, these should be gently massaged out in warm water soaks.
THE APPROACH TO THE RECURRENT INFECTION
1. Search for a predisposing cause.
a. Evaluate for seborrhea. If this is evident, look for a cause of the seborrhea.
b. Evaluate for evidence of ectoparasitic disease. Be sure to search repeatedly for demodex in any case of recurrent deep pyoderma, particularly pododermatitis. Biopsies are sometimes necessary to demonstrate mites in such cases.
c. Check for thyroid function, even in animals that are not overtly seborrheic.
d. Skin test, or undertake in vitro tests for atopy, even if animals are not pruritic when their pyoderma is controlled.
e. Do an elimination diet for food allergy, again, even if the animal is not pruritic when the pyoderma is controlled.
f. Unfortunately, work-up for immunological defects is not generally available, but should be pursued if possible if all of the above are negative.
2. Therapy for the recurrent case with no apparent cause.
a. Be sure to use the appropriate antibiotic therapy supported by results of in vitro sensitivity tests. Bactericidal therapy is preferred in recurrent cases.
b. Use good supporting antibacterial shampoos. These may be alternated with antiseborrhoeic shampoos if seborrhoea is evident.
c. Consider using immunotherapy with a staphylococcal product e.g., Staph Phage Lysate (Delmont Labs, Swarthmore, PA, USA).
d. As a last resort some clinicians advocate:
i. Continued antibiotic therapy in normal doses,
ii. Intermittent full courses at full dosage with one month on and one month off.
iii. Intermittent full dose therapy on, say, two consecutive days each week.
iv. Continual low dose therapy, which seems conceptually the least desirable approach.
Speaker Information
(click the speaker's name to view other papers and abstracts submitted by this speaker)
Richard EW Halliwell, MA, VetMB, PhD, MRCVS, DECVD
Professor, University of Edinburgh, Royal (Dick) School of Veterinary Studies, Summerhall
Edinburgh, UK
Canine Recurrent Pyoderma--Finding the Causes & Successful Management
Introduction and General Information
Pyoderma
Pyoderma is second only to flea allergy dermatitis in North America, among the most common diseases seen in small animal practice worldwide.
Recurrent Pyoderma
Refers to bacterial infections that respond completely to appropriate systemic and topical antibacterial therapy leaving the dog apparently normal between episodes of infection. Many dogs with pyoderma respond appropriately to initial therapy and pyoderma does not reoccur. An unknown percentage of dogs with pyoderma recrudesce after apparent recovery. Recurrent superficial pyoderma is much more common than recurrent deep pyoderma, many apparent cases of recurrent deep pyoderma are cases where complete cure was never achieved. Idiopathic recurrent pyoderma--appropriate diagnostic tests have failed to reveal an underlying cause.
Underlying Causes of Recurrent Pyoderma
DeBoer has produced the most logical subdivisions. This listing has been adapted from his classification:
1. Persistent underlying skin disease
2. Bacterial hypersensitivity
3. Immunodeficiency
4. Resistant strains of Staphylococcus intermedius (or other Staphylococcus--S. schleiferi, S. aureus)
5. Non-staphylococcal pyoderma
Bacterial Hypersensitivity
The concept of 'bacterial hypersensitivity' remains controversial. It is likely that some of the severe, self-perpetuating inflammation and pruritus seen with pyoderma is due to hypersensitivity to bacterial products. Fadok has speculated that hypersensitivity to super-antigens may play a role in severe inflammation seen with some canine pyoderma. Morales, Schultz & DeBoer substantiated an association between anti-staphylococcal antibodies and pyoderma subgroups.
Immunodeficiency
Despite its attractiveness as a concept, immunodeficiency is a rare cause of recurrent pyoderma.
Resistant Strains of Staphylococcus spp.
Multi-resistant strains of S. intermedius are uncommon but over-diagnosed. S. intermedius maintains a propensity not to develop resistance to cephalosporins, beta lactamase-resistant penicillins and fluoroquinolones. There has been little change in antibiotic susceptibility patterns in much of the world over the past two decades until recently.
Newer Data on Staphylococcal Infections
Staphylococcal infections in domestic animals have become more problematic during the past 5 years. For many years, veterinarians concentrated on managing infections caused by S. intermedius in dogs, cats, horses. S. schleiferi (coagulase positive or negative) was viewed as an uncommon pathogen of dogs and humans. S. aureus was relegated to discussions about humans. Currently, S. aureus is being identified with increasing frequency as a pathogen in domestic animals and as a cause of skin disease.
Methicillin resistance (MR) is being recognized with increased frequency in veterinary medicine and will have substantial impact on how we manage staphylococcal skin disease in the future. Methicillin resistance is reported in S. aureus (hospital or community acquired HA-MRSA & CA-MRSA), S. intermedius (MRSI), & S. schleiferi (MRSS).
Empirical treatment of staphylococcal infection has been the norm in dogs. Only refractory cases have been cultured routinely. This may have lead to lack of identification of MR. In human medicine, the use of fluoroquinolones may initiate enhanced MR in S. aureus. In work done in Philadelphia by Morris, MR in S. intermedius is increasing. The most reliable antibiotics against MRSI in this work were chloramphenicol and potentiated sulfonamides.
MR in staphylococci causing skin disease in domestic animals is still uncommon. However, this may be changing. Large urban centers with multiple medical schools may experience more antimicrobial pressure. This may be reflected in the data of Morris in Philadelphia. A similar phenomenon may be occurring in other urban centers globally.
We may be reaching the day when bacterial culture and sensitivity should be recommended for pyoderma that have not responded to appropriate initial empirical therapy.
Why are 'Resistant' Strains Over-diagnosed?
1. Skin perfusion--less than ideal for establishing adequate dosages of antibiotics, in comparison to other body tissues.
2. Dosages of antibiotics--largely empirical until recent years.
3. Deep pyoderma--sequestered foci of infection, foreign body granulomatous response, antibiotic inactivation by inflammatory products compromise effective antibiotic dosing.
4. Antibiotics where dosing can safely be increased in deep pyoderma--cephalosporins, fluoroquinolones, oxacillin, clavulanic acid-potentiated amoxicillin.
Non-Staphylococcal Pyoderma
This is uncommon to rare as a primary event. Culture of organisms other than S. intermedius commonly indicates secondary invaders or environmental contamination of the culture. Occasionally, infections are caused by Pseudomonas, Proteus, Escherichia coli, Enterobacter.
Post-grooming furunculosis is associated with diluted, contaminated shampoos (self-serve dog washing facilities), follicular trauma? P. aeruginosa may be most common.
Persistent Underlying Skin Disease
This is the most commonly documented cause of canine recurrent pyoderma. Diseases include non-parasitic allergic diseases (topic dermatitis, food allergy), parasitic allergic diseases (flea allergy, scabies, cheyletiellosis), demodicosis, endocrine diseases (hypothyroidism, hyperglucocorticoidism (primary or iatrogenic), diseases of cornification--(seborrhea), other infectious skin diseases, genodermatoses (especially hereditary dermatoses involving defects in hair follicles), occult neoplasia (solar-induced squamous cell carcinoma & other tumors), and immunodeficiency--(congenital, acquired).
Pruritus and Recurrent Pyoderma
The presence or absence of pruritus is a key feature in differentiating persistent underlying skin diseases. Common pruritic, persistent underlying skin diseases are atopic dermatitis, food allergy, flea allergy dermatitis, cheyletiellosis, sarcoptic acariasis, and primary cornification defects.
Approach to Recurrent Pyoderma
1. Aggressively pursue the diagnosis of possible persistent underlying skin diseases.
2. Manage the underlying skin diseases--long-term, consistent (in our clinic, canine atopic dermatitis is the most commonly diagnosed underlying skin disease).
3. Manage the episode of recurrent pyoderma and prevent episodes or diminish frequency of recurrence.
Goals of Long-term Management
1. Establish realistic owner expectations
2. Successfully treat pyoderma, maintaining therapy for long enough to ensure cure:
a. Superficial pyoderma--minimum of 3 weeks, at least 1 week beyond clinical cure.
b. Deep pyoderma--minimum of 6 weeks, at least 2 weeks beyond apparent cure.
Prevent or Diminish Frequency of Recurrence--An Overview
Topical antibacterial shampoo therapy should be used adjunctively in all recurrent pyoderma, continue indefinitely in idiopathic cases.
Immunomodulatory therapy using adjunctive, killed bacterial preparations or non-bacterial immunostimulants is attempted in dogs with confirmed or suspected defects of the immune system or in dogs with idiopathic recurrent pyoderma.
Extended regimens of antibiotic therapy are a last resort.
Topical Antibacterial Shampoo Therapy
Rationale--decrease surface bacteria, limit re-colonization, diminish frequency of recurrence?
Active agents--chlorhexidine, benzoyl peroxide, benzoyl peroxide and sulfur, triclosan, ethyl lactate.
Frequency--2x / week, 15 minutes contact time.
Improvement in patient attitude and owner encouragement.
Immunomodulatory Therapy
Rationale--stimulate immune surveillance, alter response to bacterial allergen, diminish recurrence, (controversial).
Staphage LysateR--SPL--(Delmont Laboratories, Swarthmore, Pennsylvania, USA)--S. aureus, serotypes I & III, protein A.
Extended Antibiotic Regimens
Diminish recurrence by preventing re-infection.
Dosing--3 consecutive days/week (full daily dose).
Antibiotic choices--cephalexin, cefpodoxime, enrofloxacin, marbofloxacin, other fluoroquinolones, clavulanate-potentiated amoxicillin, oxacillin.
Extended antibiotic regimens--consider as a last resort.
Extended Antibiotic Regimens--Antibiotic Choices
Underlined antibiotics are viewed as good choices for extended regimens
1. Narrow spectrum antibiotics:
a. Isoxazolyl penicillins--oxacillin, cloxacillin, dicloxacillin, nafcillin
b. Macrolide group--erythromycin, tylosin
c. Lincosamide group--lincomycin, clindamycin
2. Broad spectrum antibiotics:
a. Trimethoprim & ormetoprim-potentiated sulfonamides
b. Aminopenicillin & B-lactamase inhibitor--clavulanic acid-potentiated amoxicillin
3. First generation (group 2) oral cephalosporins--(cephalexin, cefadroxil, cephradine)
4. Third generation (group 5) oral cephalosporins--(cefpodoxime)
5. Fluoroquinolones--enrofloxacin, marbofloxacin
Compliance
Client education increases compliance--extended regimens with once a day dosing may lead to greater compliance.
Treatment Failure in Recurrent Pyoderma
Underlying causes--not identified or cannot be managed.
Inadequate duration of curative antibiotic therapy before switching to extended regimens.
Inadequate owner compliance.
Antibiotic resistance
References
1. DeBoer DJ. Management of chronic and recurrent pyoderma in the dog, in Bonagura JD (ed): Kirk's Current Veterinary Therapy XII. Philadelphia, WB Saunders, 1995, pp 611-617.
2. Ihrke PJ. Bacterial infections of the skin. In: Greene CE (ed): Infectious Diseases of the Dog and Cat, Third Edition, Philadelphia, WB Saunders Co, 2006, 807-815.
3. Carlotti DN, Jasmin P, Gardey L, Sanquer A. Evaluation of cephalexin intermittent therapy (weekend therapy) in the control of recurrent idiopathic pyoderma in dogs: a randomized double-blinded, placebo-controlled study. Vet Dermatol 2004;15s: 8-9.
4. Gross TL, Ihrke PJ, Walder EJ, Affolter VK. Skin Diseases of the Dog and Cat: Clinical and Histopathologic Diagnosis. Blackwell, Oxford, pp 222-225, 4-9, 406-410, 420-435, 2005.
5. Morris DO, Rook KA, Shofer FS, Rankin SC. Screening of S. aureus, S. intermedius, and S. schleiferi isolates obtained from small companion animals for antimicrobial resistance: Vet Dermatol 17: 332-337, 2006.
Speaker Information
(click the speaker's name to view other papers and abstracts submitted by this speaker)
Peter J Ihrke, VMD, DACVD
School of Veterinary Medicine
University of California
Davis, California, USA
Pyoderma
Pyoderma is second only to flea allergy dermatitis in North America, among the most common diseases seen in small animal practice worldwide.
Recurrent Pyoderma
Refers to bacterial infections that respond completely to appropriate systemic and topical antibacterial therapy leaving the dog apparently normal between episodes of infection. Many dogs with pyoderma respond appropriately to initial therapy and pyoderma does not reoccur. An unknown percentage of dogs with pyoderma recrudesce after apparent recovery. Recurrent superficial pyoderma is much more common than recurrent deep pyoderma, many apparent cases of recurrent deep pyoderma are cases where complete cure was never achieved. Idiopathic recurrent pyoderma--appropriate diagnostic tests have failed to reveal an underlying cause.
Underlying Causes of Recurrent Pyoderma
DeBoer has produced the most logical subdivisions. This listing has been adapted from his classification:
1. Persistent underlying skin disease
2. Bacterial hypersensitivity
3. Immunodeficiency
4. Resistant strains of Staphylococcus intermedius (or other Staphylococcus--S. schleiferi, S. aureus)
5. Non-staphylococcal pyoderma
Bacterial Hypersensitivity
The concept of 'bacterial hypersensitivity' remains controversial. It is likely that some of the severe, self-perpetuating inflammation and pruritus seen with pyoderma is due to hypersensitivity to bacterial products. Fadok has speculated that hypersensitivity to super-antigens may play a role in severe inflammation seen with some canine pyoderma. Morales, Schultz & DeBoer substantiated an association between anti-staphylococcal antibodies and pyoderma subgroups.
Immunodeficiency
Despite its attractiveness as a concept, immunodeficiency is a rare cause of recurrent pyoderma.
Resistant Strains of Staphylococcus spp.
Multi-resistant strains of S. intermedius are uncommon but over-diagnosed. S. intermedius maintains a propensity not to develop resistance to cephalosporins, beta lactamase-resistant penicillins and fluoroquinolones. There has been little change in antibiotic susceptibility patterns in much of the world over the past two decades until recently.
Newer Data on Staphylococcal Infections
Staphylococcal infections in domestic animals have become more problematic during the past 5 years. For many years, veterinarians concentrated on managing infections caused by S. intermedius in dogs, cats, horses. S. schleiferi (coagulase positive or negative) was viewed as an uncommon pathogen of dogs and humans. S. aureus was relegated to discussions about humans. Currently, S. aureus is being identified with increasing frequency as a pathogen in domestic animals and as a cause of skin disease.
Methicillin resistance (MR) is being recognized with increased frequency in veterinary medicine and will have substantial impact on how we manage staphylococcal skin disease in the future. Methicillin resistance is reported in S. aureus (hospital or community acquired HA-MRSA & CA-MRSA), S. intermedius (MRSI), & S. schleiferi (MRSS).
Empirical treatment of staphylococcal infection has been the norm in dogs. Only refractory cases have been cultured routinely. This may have lead to lack of identification of MR. In human medicine, the use of fluoroquinolones may initiate enhanced MR in S. aureus. In work done in Philadelphia by Morris, MR in S. intermedius is increasing. The most reliable antibiotics against MRSI in this work were chloramphenicol and potentiated sulfonamides.
MR in staphylococci causing skin disease in domestic animals is still uncommon. However, this may be changing. Large urban centers with multiple medical schools may experience more antimicrobial pressure. This may be reflected in the data of Morris in Philadelphia. A similar phenomenon may be occurring in other urban centers globally.
We may be reaching the day when bacterial culture and sensitivity should be recommended for pyoderma that have not responded to appropriate initial empirical therapy.
Why are 'Resistant' Strains Over-diagnosed?
1. Skin perfusion--less than ideal for establishing adequate dosages of antibiotics, in comparison to other body tissues.
2. Dosages of antibiotics--largely empirical until recent years.
3. Deep pyoderma--sequestered foci of infection, foreign body granulomatous response, antibiotic inactivation by inflammatory products compromise effective antibiotic dosing.
4. Antibiotics where dosing can safely be increased in deep pyoderma--cephalosporins, fluoroquinolones, oxacillin, clavulanic acid-potentiated amoxicillin.
Non-Staphylococcal Pyoderma
This is uncommon to rare as a primary event. Culture of organisms other than S. intermedius commonly indicates secondary invaders or environmental contamination of the culture. Occasionally, infections are caused by Pseudomonas, Proteus, Escherichia coli, Enterobacter.
Post-grooming furunculosis is associated with diluted, contaminated shampoos (self-serve dog washing facilities), follicular trauma? P. aeruginosa may be most common.
Persistent Underlying Skin Disease
This is the most commonly documented cause of canine recurrent pyoderma. Diseases include non-parasitic allergic diseases (topic dermatitis, food allergy), parasitic allergic diseases (flea allergy, scabies, cheyletiellosis), demodicosis, endocrine diseases (hypothyroidism, hyperglucocorticoidism (primary or iatrogenic), diseases of cornification--(seborrhea), other infectious skin diseases, genodermatoses (especially hereditary dermatoses involving defects in hair follicles), occult neoplasia (solar-induced squamous cell carcinoma & other tumors), and immunodeficiency--(congenital, acquired).
Pruritus and Recurrent Pyoderma
The presence or absence of pruritus is a key feature in differentiating persistent underlying skin diseases. Common pruritic, persistent underlying skin diseases are atopic dermatitis, food allergy, flea allergy dermatitis, cheyletiellosis, sarcoptic acariasis, and primary cornification defects.
Approach to Recurrent Pyoderma
1. Aggressively pursue the diagnosis of possible persistent underlying skin diseases.
2. Manage the underlying skin diseases--long-term, consistent (in our clinic, canine atopic dermatitis is the most commonly diagnosed underlying skin disease).
3. Manage the episode of recurrent pyoderma and prevent episodes or diminish frequency of recurrence.
Goals of Long-term Management
1. Establish realistic owner expectations
2. Successfully treat pyoderma, maintaining therapy for long enough to ensure cure:
a. Superficial pyoderma--minimum of 3 weeks, at least 1 week beyond clinical cure.
b. Deep pyoderma--minimum of 6 weeks, at least 2 weeks beyond apparent cure.
Prevent or Diminish Frequency of Recurrence--An Overview
Topical antibacterial shampoo therapy should be used adjunctively in all recurrent pyoderma, continue indefinitely in idiopathic cases.
Immunomodulatory therapy using adjunctive, killed bacterial preparations or non-bacterial immunostimulants is attempted in dogs with confirmed or suspected defects of the immune system or in dogs with idiopathic recurrent pyoderma.
Extended regimens of antibiotic therapy are a last resort.
Topical Antibacterial Shampoo Therapy
Rationale--decrease surface bacteria, limit re-colonization, diminish frequency of recurrence?
Active agents--chlorhexidine, benzoyl peroxide, benzoyl peroxide and sulfur, triclosan, ethyl lactate.
Frequency--2x / week, 15 minutes contact time.
Improvement in patient attitude and owner encouragement.
Immunomodulatory Therapy
Rationale--stimulate immune surveillance, alter response to bacterial allergen, diminish recurrence, (controversial).
Staphage LysateR--SPL--(Delmont Laboratories, Swarthmore, Pennsylvania, USA)--S. aureus, serotypes I & III, protein A.
Extended Antibiotic Regimens
Diminish recurrence by preventing re-infection.
Dosing--3 consecutive days/week (full daily dose).
Antibiotic choices--cephalexin, cefpodoxime, enrofloxacin, marbofloxacin, other fluoroquinolones, clavulanate-potentiated amoxicillin, oxacillin.
Extended antibiotic regimens--consider as a last resort.
Extended Antibiotic Regimens--Antibiotic Choices
Underlined antibiotics are viewed as good choices for extended regimens
1. Narrow spectrum antibiotics:
a. Isoxazolyl penicillins--oxacillin, cloxacillin, dicloxacillin, nafcillin
b. Macrolide group--erythromycin, tylosin
c. Lincosamide group--lincomycin, clindamycin
2. Broad spectrum antibiotics:
a. Trimethoprim & ormetoprim-potentiated sulfonamides
b. Aminopenicillin & B-lactamase inhibitor--clavulanic acid-potentiated amoxicillin
3. First generation (group 2) oral cephalosporins--(cephalexin, cefadroxil, cephradine)
4. Third generation (group 5) oral cephalosporins--(cefpodoxime)
5. Fluoroquinolones--enrofloxacin, marbofloxacin
Compliance
Client education increases compliance--extended regimens with once a day dosing may lead to greater compliance.
Treatment Failure in Recurrent Pyoderma
Underlying causes--not identified or cannot be managed.
Inadequate duration of curative antibiotic therapy before switching to extended regimens.
Inadequate owner compliance.
Antibiotic resistance
References
1. DeBoer DJ. Management of chronic and recurrent pyoderma in the dog, in Bonagura JD (ed): Kirk's Current Veterinary Therapy XII. Philadelphia, WB Saunders, 1995, pp 611-617.
2. Ihrke PJ. Bacterial infections of the skin. In: Greene CE (ed): Infectious Diseases of the Dog and Cat, Third Edition, Philadelphia, WB Saunders Co, 2006, 807-815.
3. Carlotti DN, Jasmin P, Gardey L, Sanquer A. Evaluation of cephalexin intermittent therapy (weekend therapy) in the control of recurrent idiopathic pyoderma in dogs: a randomized double-blinded, placebo-controlled study. Vet Dermatol 2004;15s: 8-9.
4. Gross TL, Ihrke PJ, Walder EJ, Affolter VK. Skin Diseases of the Dog and Cat: Clinical and Histopathologic Diagnosis. Blackwell, Oxford, pp 222-225, 4-9, 406-410, 420-435, 2005.
5. Morris DO, Rook KA, Shofer FS, Rankin SC. Screening of S. aureus, S. intermedius, and S. schleiferi isolates obtained from small companion animals for antimicrobial resistance: Vet Dermatol 17: 332-337, 2006.
Speaker Information
(click the speaker's name to view other papers and abstracts submitted by this speaker)
Peter J Ihrke, VMD, DACVD
School of Veterinary Medicine
University of California
Davis, California, USA
Update on Therapy of Canine Pyoderma
Introduction
Canine pyoderma is a complex of diseases involving bacterial infection at different levels of the skin (Table 1) and requiring different approaches to therapy. These diseases are nearly always secondary and so it is important to identify underlying factors. Commonly these are allergies but endocrinopathy, immunodeficiency, ectoparasitic infestation, follicular dysplasia and breed predisposition may be involved. Diagnosis of underlying conditions may not be easy. Treatment during the diagnostic phase should be designed to advance diagnosis and avoid camouflaging diagnostic clinical signs. Antibiotic therapy is a good diagnostic strategy as it eliminates pyoderma and helps expose underlying conditions.
This presentation assumes that a diagnosis has been made and deals with current approaches to the treatment of the different forms of infection. Treatment of underlying causes is not covered.
Table 1. Classification of canine pyoderma.
Surface pyoderma
Acute moist dermatitis
Skin fold pyoderma
Microbial overgrowth*
Superficial pyoderma
Impetigo ("puppy pyoderma")
Mucocutaneous pyoderma
Superficial spreading pyoderma
Superficial folliculitis
Deep pyoderma
Muzzle folliculitis & furunculosis
Localised deep pyodermas (nasal, pedal & pressure point pyodermas, pyotraumatic folliculitis & furunculosis)
Generalised deep pyoderma
Bacterial granulomas
*Not strictly pyoderma. Commonly both pathogenic staphylococci and Malassezia are present.
Surface Pyoderma
Acute Moist Dermatitis. Prevention of further trauma is essential and will sometimes allow healing without further therapy. Ensure that there is no underlying folliculitis or furunculosis. Because the epidermal damage is a consequence of trauma, healing is rapid. However, lesions are often painful and topical therapy, requiring direct contact with skin, can be hazardous. Topical antibiotic and steroid gels or creams are effective but spraying with a soothing, antimicrobial, astringent preparation has been shown to be as effective1 and is likely to be less hazardous. Lesions should be substantially healed in 7-10 days. Where there is marked pruritus, systemic glucocorticoids may be required.
Skin Fold Pyoderma. Ideally, folds are removed surgically. If surgery is not feasible, measures to render the microenvironment within the fold inhospitable to bacteria and yeasts are required. Cleansing every 2-3 days with an antimicrobial shampoo is effective. Benzoyl peroxide, chlorhexidine, and chlorhexidine and miconazole are effective. Chlorhexidine is quite unstable and so it is advisable to select well-formulated preparations with published efficacy against both bacteria and Malassezia.2 (Lloyd 1999) Benzoyl peroxide must used with care as animals may develop sensitivity and it can be irritant. Ethyl lactate may be effective in milder cases and has low irritancy. Intervals between shampooing may be extended by the use of antimicrobial creams and gels. Spraying with a soothing, antimicrobial, astringent preparation may also be effective.
Superficial Pyoderma
Impetigo normally responds to antimicrobial shampoos. Use on two or three occasions over a period of 7-10 days should be effective in uncomplicated cases. Spontaneous resolution commonly occurs.
Mucocutaneous Pyoderma may respond to treatment with antibacterial shampoos, as described above, followed by the use of antibacterial ointment, such as mupirocin. Daily treatment for two weeks and then once or twice a week may be effective. Following resolution, the disease may remain in abeyance but commonly repeated treatment is required. With deeper or more extensive infection, or if topical treatment is difficult, systemic antibiotic is required. Treatment for 4 weeks or more may be necessary. If not successful, further diagnostic procedures, including biopsy, are required.
Superficial Folliculitis and Superficial Spreading Pyoderma. Normally systemic antibiotic therapy is used. Bacteriostatic antibiotics are effective but bactericides are preferable. Treatment for at least one week beyond clinical cure is advisable. Recovery may be promoted by use of antibacterial shampoos containing chlorhexidine or benzoyl peroxide, or in milder cases ethyl lactate, which aid removal of crusts and reduce surface bacterial populations.2,3 Mild superficial pyoderma can be treated with such shampoos without systemic antibiotic but this is labour-intensive; shampooing every 2-3 days is required. Once lesion resolution occurs, shampooing can be reduced to once or twice a week; in winter weekly to monthly shampooing may be sufficient to maintain remission.
Where there is recurrent infection and underlying causes cannot be identified or controlled, long-term treatment options need to be considered. Regular shampooing with antibacterial shampoo may give control. Otherwise, the main options are pulse therapy with antibiotics and staphylococcal vaccination. Vaccination is a better choice. Well-prepared autogenous vaccines (bacterins) are effective in about 50% of cases; responding dogs do not need other therapy.4 An American bacterial lysate prepared from S. aureus, has also been shown to reduce the frequency of folliculitis and decrease the need for repeated antibiotic therapy.5 Pulse or continual low dose therapy6 should be a last resort as it may promote development of antibiotic resistance, although recent evidence indicates that this risk may be low.
In view of the fact that the causative pathogen may be harboured on the mucosae, particularly of the upper respiratory tract and anus, some clinicians have used topical antibiotic to treat the nasal and or anal mucosae. Experimental studies have shown that S. intermedius populations can be eliminated by this method using fusidic acid.7 Anecdotally, this has helped in some cases of recurrent pyoderma.
Deep Pyoderma
When deep infection occurs, there are local factors causing skin damage and more serious deficiencies in the immune system of the affected animal. If these can be resolved, recovery should be complete. Determined efforts to identify the underlying factors should be made. Demodicosis is a common cause.
With discharging lesions, antimicrobial washes and soaks are useful to remove pus and debris, and may accelerate recovery. Clipping is helpful, enables the extent of lesions to be demonstrated and can be useful in persuading clients to comply with treatment. Prolonged systemic antibiotic treatment with bactericidal antibiotic is necessary and must continue for at least two weeks beyond clinical cure. Where lesions are in areas with poor blood supply or large granulomatous lesions, fluoroquinolones, which penetrate well, are particularly useful. On rare occasions it may be necessary to use unusual antibiotics to achieve penetration, such as rifampicin.
In some cases, unusual organisms such as actinomycetes or mycobacteria are involved, and there may be concurrent infection with fungi. Careful diagnostic procedures, including discussion with the laboratory concerned, may be required as routine methods may not be effective.
Choice of Antibiotics and Dosage
Although antibiotics can be selected empirically, where recurrent infection occurs or there is a lack of response, microbiological culture and sensitivity should be carried out.8,9 Ensure that you use a reliable laboratory and question unusual results e.g., very broad resistance in an organism identified as S. intermedius; this could turn out to be a methicillin-resistant S. aureus or S. schleiferi.10,11 Remember that several different strains of pathogenic staphylococci may be present on a single animal. Thus a single sensitivity test may not give the full picture. Failure of a particular antibiotic may mean you have only eliminated part of the causative bacterial population. If in doubt, always retest. Ensure your sample contains material from deep within the lesions; biopsy may be necessary for this.
Generally, manufacturer's recommended dose rates will be effective. Occasionally you will need to use higher doses to achieve effective levels of antibiotic within lesions or to overcome low level resistance. The range of antibiotics commonly used in veterinary dermatology and their properties and use are reviewed in a special issue of Veterinary Dermatology published in 1999, which is still relevant and provides excellent summaries.12
References
1. Ascher F, Madin F, Guaguere E et al. Intérêt d'une solution topique non antibiocorticoide dans le traitement de la dermatite pyotraumatique du chien. Pratique Médicale et Chirurgicale de L'Animal de Compagnie. 1995; 30:345-354.
2. Lloyd DH, Lamport AI. Activity of chlorhexidine shampoos in vitro against Staphylococcus intermedius, Pseudomonas aeruginosa and Malassezia pachydermatis. Veterinary Record 1999; 144: 536-537.
3. De Jaham c. Effects of an ethyl lactate shampoo in conjunction with a systemic antibiotic in the treatment of canine superficial bacterial pyoderma in an open-label, non placebo-controlled study. Veterinary Therapeutics 2003; 4: 94-100.
4. Curtis CF, Lamport AI, Lloyd DH. Blinded, controlled study to investigate the efficacy of a staphylococcal autogenous bacterin for the control of canine idiopathic recurrent pyoderma. Proceedings of the 16th Annual Congress of the ESVD-ECVD, Helsinki, Finland, August 1999. p. 148.
5. Deboer DJ, Moriello KA, Thomas CB, et al. Evaluation of a commercial staphylococcal bacterin for management of idiopathic recurrent pyoderma in dogs. American Journal of Veterinary Research 1990; 51: 636-639.
6. Carlotti DN, Jasmin P, L. Gardey L, Sanquer A. (2004): Evaluation of cephalexin intermittent therapy (weekend therapy) in the control of recurrent idiopathic pyoderma in dogs: a randomized, double-blinded, placebo-controlled study. Veterinary Dermatology 2004; 15 ( s1): 7-8.
7. Saijonmaa-Koulumies L., Parsons E., Lloyd, DH. Elimination of Staphylococcus intermedius in healthy dogs by topical treatment with fusidic acid. Journal of Small Animal Practice 1998; 39: 341-7.
8. Holm BR, Petersson U, Morner A, et al. Antimicrobial resistance in staphylococci from canine pyoderma: a prospective study of first-time and recurrent cases in Sweden. Veterinary Record 2002; 151: 600-5.
9. Kruse H, Hofshagen M, Thoresen SI, et al. The antimicrobial susceptibility of Staphylococcus species isolated from canine dermatitis. Veterinary Research Communication 1996; 20: 205-14.
10. Loeffler A, Boag AK, Sung J, et al. Prevalence of methicillin-resistant Staphylococcus aureus among staff and pets in a small Animal referral hospital in the UK. Journal of Antimicrobial Chemotherapy 2005; 56: 692-7.
11. Frank, LA, Kania, SA, Hnilica, KA, et al. Isolation of Staphylococcus schleiferi from dogs with pyoderma. Journal of the American Veterinary Medical Association 2003; 222 (4); 451-4.
12. Special Issue on Antibiotics in Veterinary Dermatology. Veterinary Dermatology 1999; 10: 161-262.
Speaker Information
(click the speaker's name to view other papers and abstracts submitted by this speaker)
David Lloyd
Royal Veterinary College
Hawkshead Campus
North Mymms, Hertfordshire , United Kingdom
Canine pyoderma is a complex of diseases involving bacterial infection at different levels of the skin (Table 1) and requiring different approaches to therapy. These diseases are nearly always secondary and so it is important to identify underlying factors. Commonly these are allergies but endocrinopathy, immunodeficiency, ectoparasitic infestation, follicular dysplasia and breed predisposition may be involved. Diagnosis of underlying conditions may not be easy. Treatment during the diagnostic phase should be designed to advance diagnosis and avoid camouflaging diagnostic clinical signs. Antibiotic therapy is a good diagnostic strategy as it eliminates pyoderma and helps expose underlying conditions.
This presentation assumes that a diagnosis has been made and deals with current approaches to the treatment of the different forms of infection. Treatment of underlying causes is not covered.
Table 1. Classification of canine pyoderma.
Surface pyoderma
Acute moist dermatitis
Skin fold pyoderma
Microbial overgrowth*
Superficial pyoderma
Impetigo ("puppy pyoderma")
Mucocutaneous pyoderma
Superficial spreading pyoderma
Superficial folliculitis
Deep pyoderma
Muzzle folliculitis & furunculosis
Localised deep pyodermas (nasal, pedal & pressure point pyodermas, pyotraumatic folliculitis & furunculosis)
Generalised deep pyoderma
Bacterial granulomas
*Not strictly pyoderma. Commonly both pathogenic staphylococci and Malassezia are present.
Surface Pyoderma
Acute Moist Dermatitis. Prevention of further trauma is essential and will sometimes allow healing without further therapy. Ensure that there is no underlying folliculitis or furunculosis. Because the epidermal damage is a consequence of trauma, healing is rapid. However, lesions are often painful and topical therapy, requiring direct contact with skin, can be hazardous. Topical antibiotic and steroid gels or creams are effective but spraying with a soothing, antimicrobial, astringent preparation has been shown to be as effective1 and is likely to be less hazardous. Lesions should be substantially healed in 7-10 days. Where there is marked pruritus, systemic glucocorticoids may be required.
Skin Fold Pyoderma. Ideally, folds are removed surgically. If surgery is not feasible, measures to render the microenvironment within the fold inhospitable to bacteria and yeasts are required. Cleansing every 2-3 days with an antimicrobial shampoo is effective. Benzoyl peroxide, chlorhexidine, and chlorhexidine and miconazole are effective. Chlorhexidine is quite unstable and so it is advisable to select well-formulated preparations with published efficacy against both bacteria and Malassezia.2 (Lloyd 1999) Benzoyl peroxide must used with care as animals may develop sensitivity and it can be irritant. Ethyl lactate may be effective in milder cases and has low irritancy. Intervals between shampooing may be extended by the use of antimicrobial creams and gels. Spraying with a soothing, antimicrobial, astringent preparation may also be effective.
Superficial Pyoderma
Impetigo normally responds to antimicrobial shampoos. Use on two or three occasions over a period of 7-10 days should be effective in uncomplicated cases. Spontaneous resolution commonly occurs.
Mucocutaneous Pyoderma may respond to treatment with antibacterial shampoos, as described above, followed by the use of antibacterial ointment, such as mupirocin. Daily treatment for two weeks and then once or twice a week may be effective. Following resolution, the disease may remain in abeyance but commonly repeated treatment is required. With deeper or more extensive infection, or if topical treatment is difficult, systemic antibiotic is required. Treatment for 4 weeks or more may be necessary. If not successful, further diagnostic procedures, including biopsy, are required.
Superficial Folliculitis and Superficial Spreading Pyoderma. Normally systemic antibiotic therapy is used. Bacteriostatic antibiotics are effective but bactericides are preferable. Treatment for at least one week beyond clinical cure is advisable. Recovery may be promoted by use of antibacterial shampoos containing chlorhexidine or benzoyl peroxide, or in milder cases ethyl lactate, which aid removal of crusts and reduce surface bacterial populations.2,3 Mild superficial pyoderma can be treated with such shampoos without systemic antibiotic but this is labour-intensive; shampooing every 2-3 days is required. Once lesion resolution occurs, shampooing can be reduced to once or twice a week; in winter weekly to monthly shampooing may be sufficient to maintain remission.
Where there is recurrent infection and underlying causes cannot be identified or controlled, long-term treatment options need to be considered. Regular shampooing with antibacterial shampoo may give control. Otherwise, the main options are pulse therapy with antibiotics and staphylococcal vaccination. Vaccination is a better choice. Well-prepared autogenous vaccines (bacterins) are effective in about 50% of cases; responding dogs do not need other therapy.4 An American bacterial lysate prepared from S. aureus, has also been shown to reduce the frequency of folliculitis and decrease the need for repeated antibiotic therapy.5 Pulse or continual low dose therapy6 should be a last resort as it may promote development of antibiotic resistance, although recent evidence indicates that this risk may be low.
In view of the fact that the causative pathogen may be harboured on the mucosae, particularly of the upper respiratory tract and anus, some clinicians have used topical antibiotic to treat the nasal and or anal mucosae. Experimental studies have shown that S. intermedius populations can be eliminated by this method using fusidic acid.7 Anecdotally, this has helped in some cases of recurrent pyoderma.
Deep Pyoderma
When deep infection occurs, there are local factors causing skin damage and more serious deficiencies in the immune system of the affected animal. If these can be resolved, recovery should be complete. Determined efforts to identify the underlying factors should be made. Demodicosis is a common cause.
With discharging lesions, antimicrobial washes and soaks are useful to remove pus and debris, and may accelerate recovery. Clipping is helpful, enables the extent of lesions to be demonstrated and can be useful in persuading clients to comply with treatment. Prolonged systemic antibiotic treatment with bactericidal antibiotic is necessary and must continue for at least two weeks beyond clinical cure. Where lesions are in areas with poor blood supply or large granulomatous lesions, fluoroquinolones, which penetrate well, are particularly useful. On rare occasions it may be necessary to use unusual antibiotics to achieve penetration, such as rifampicin.
In some cases, unusual organisms such as actinomycetes or mycobacteria are involved, and there may be concurrent infection with fungi. Careful diagnostic procedures, including discussion with the laboratory concerned, may be required as routine methods may not be effective.
Choice of Antibiotics and Dosage
Although antibiotics can be selected empirically, where recurrent infection occurs or there is a lack of response, microbiological culture and sensitivity should be carried out.8,9 Ensure that you use a reliable laboratory and question unusual results e.g., very broad resistance in an organism identified as S. intermedius; this could turn out to be a methicillin-resistant S. aureus or S. schleiferi.10,11 Remember that several different strains of pathogenic staphylococci may be present on a single animal. Thus a single sensitivity test may not give the full picture. Failure of a particular antibiotic may mean you have only eliminated part of the causative bacterial population. If in doubt, always retest. Ensure your sample contains material from deep within the lesions; biopsy may be necessary for this.
Generally, manufacturer's recommended dose rates will be effective. Occasionally you will need to use higher doses to achieve effective levels of antibiotic within lesions or to overcome low level resistance. The range of antibiotics commonly used in veterinary dermatology and their properties and use are reviewed in a special issue of Veterinary Dermatology published in 1999, which is still relevant and provides excellent summaries.12
References
1. Ascher F, Madin F, Guaguere E et al. Intérêt d'une solution topique non antibiocorticoide dans le traitement de la dermatite pyotraumatique du chien. Pratique Médicale et Chirurgicale de L'Animal de Compagnie. 1995; 30:345-354.
2. Lloyd DH, Lamport AI. Activity of chlorhexidine shampoos in vitro against Staphylococcus intermedius, Pseudomonas aeruginosa and Malassezia pachydermatis. Veterinary Record 1999; 144: 536-537.
3. De Jaham c. Effects of an ethyl lactate shampoo in conjunction with a systemic antibiotic in the treatment of canine superficial bacterial pyoderma in an open-label, non placebo-controlled study. Veterinary Therapeutics 2003; 4: 94-100.
4. Curtis CF, Lamport AI, Lloyd DH. Blinded, controlled study to investigate the efficacy of a staphylococcal autogenous bacterin for the control of canine idiopathic recurrent pyoderma. Proceedings of the 16th Annual Congress of the ESVD-ECVD, Helsinki, Finland, August 1999. p. 148.
5. Deboer DJ, Moriello KA, Thomas CB, et al. Evaluation of a commercial staphylococcal bacterin for management of idiopathic recurrent pyoderma in dogs. American Journal of Veterinary Research 1990; 51: 636-639.
6. Carlotti DN, Jasmin P, L. Gardey L, Sanquer A. (2004): Evaluation of cephalexin intermittent therapy (weekend therapy) in the control of recurrent idiopathic pyoderma in dogs: a randomized, double-blinded, placebo-controlled study. Veterinary Dermatology 2004; 15 ( s1): 7-8.
7. Saijonmaa-Koulumies L., Parsons E., Lloyd, DH. Elimination of Staphylococcus intermedius in healthy dogs by topical treatment with fusidic acid. Journal of Small Animal Practice 1998; 39: 341-7.
8. Holm BR, Petersson U, Morner A, et al. Antimicrobial resistance in staphylococci from canine pyoderma: a prospective study of first-time and recurrent cases in Sweden. Veterinary Record 2002; 151: 600-5.
9. Kruse H, Hofshagen M, Thoresen SI, et al. The antimicrobial susceptibility of Staphylococcus species isolated from canine dermatitis. Veterinary Research Communication 1996; 20: 205-14.
10. Loeffler A, Boag AK, Sung J, et al. Prevalence of methicillin-resistant Staphylococcus aureus among staff and pets in a small Animal referral hospital in the UK. Journal of Antimicrobial Chemotherapy 2005; 56: 692-7.
11. Frank, LA, Kania, SA, Hnilica, KA, et al. Isolation of Staphylococcus schleiferi from dogs with pyoderma. Journal of the American Veterinary Medical Association 2003; 222 (4); 451-4.
12. Special Issue on Antibiotics in Veterinary Dermatology. Veterinary Dermatology 1999; 10: 161-262.
Speaker Information
(click the speaker's name to view other papers and abstracts submitted by this speaker)
David Lloyd
Royal Veterinary College
Hawkshead Campus
North Mymms, Hertfordshire , United Kingdom
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