Comparison of a chlorhexidine and a benzoyl peroxide shampoo as sole treatment in canine superficial pyoderma

The clinical and antibacterial efficacy of two shampoos used as a sole antibacterial treatment in dogs with superficial pyoderma were investigated and compared. In a randomised, partially blinded study, a 3 per cent chlorhexidine gluconate shampoo (Chlorhex 3; Leo Animal Health) was compared against a 2.5 per cent benzoyl peroxide shampoo (Paxcutol; Virbac) in 22 dogs with superficial pyoderma. Dogs were washed two to three times weekly with a 10-minute contact time over 21 days. Clinical scores and bacterial counts were assessed on days 1, 8 and 22 and compared within and between treatment groups; overall response was assessed at the end of the study. Twenty dogs completed the study; 15 (68.2 per cent) showed an overall clinical improvement and the clinical signs resolved in three chlorhexidine-treated dogs. In the chlorhexidine-treated group, scores for papules/pustules (P<0.001), investigator-assessed pruritus (P=0.003), total bacterial counts (P=0.003) and counts for coagulase-positive staphylococci (P=0.003) were reduced after three weeks. Scores and bacterial counts did not vary significantly in the benzoyl peroxide-treated group.     

The effectiveness of systemic antimicrobial treatment in canine superficial and deep pyoderma: a systematic review

Aim – To identify and evaluate existing evidence for the effectiveness of systemic antimicrobial treatments for naturally occurring superficial and deep canine pyoderma. Method – Electronic searches of PubMed, MEDLINE and CAB Direct were carried out (25 May 2011) without date or language restrictions. Proceedings of ESVD/ECVD, AAVD/ACVD, NAVDF and WCVD annual congresses were searched. Unpublished studies were sought via the Veterinary Dermatology discussion list and Veterinary Information Network. Results – Seventeen full‐length, peer‐reviewed controlled trials reporting clinical outcomes of systemic antimicrobial treatment for canine pyoderma were identified. Outcomes specific to superficial or deep pyoderma were reported in nine and five studies, respectively. Five studies reported outcomes only for nondifferentiated pyoderma depth. Heterogeneity of study designs and outcome measures made meta‐analysis inappropriate. A good level of evidence was identified supporting the high efficacy of subcutaneously injected cefovecin in superficial pyoderma and for oral amoxicillin–clavulanic acid in deep pyoderma. A fair level of evidence was identified for moderate to high efficacy of oral amoxicillin–clavulanic acid, clindamycin, cefadroxil, trimethoprim–sulphamethoxazole and sulfadimethoxine–ormetoprim in superficial pyoderma and oral pradofloxacin, oral cefadroxil and subcutaneously injected cefovecin in deep pyoderma. Eleven trials reported observations of adverse effects in treated pyoderma cases by intervention group; four dogs were withdrawn owing to the severity of adverse effects. Conclusions – There is a need for greater numbers of adequately sized, blinded, randomized controlled trials evaluating systemic antimicrobial interventions for canine pyoderma. Improved differentiation between superficial and deep pyoderma in outcome reporting, outcome measure standardization and association of outcomes with causative bacterial species and their resistance patterns are required.     

Clindamycin hydrochloride and clavulanate-amoxycillin in the treatment of canine superficial pyoderma.

A masked, randomised, controlled clinical trial for the treatment of canine superficial pyoderma was undertaken. Dogs with a clinical diagnosis of superficial pyoderma, supported by bacterial culture were admitted to the trial and randomly assigned to treatment with either clindamycin hydrochloride at 5.5 mg/kg twice daily or clavulanate-amoxycillin at 12.5 mg/kg twice daily. After 21 days the animals were re-assessed, and therapy was continued for a further 21 days in the dogs with persistent lesions if bacterial culture demonstrated continued sensitivity. Twenty-nine dogs were treated with clindamycin hydrochloride and 27 with clavulanate-amoxycillin. Complete cure was obtained after three weeks in 17 (59 per cent) of the clindamycin-treated cases, but in only eight (30 per cent) of the clavulanate-amoxycillin treated group. Clindamycin was significantly more effective than clavulanate-amoxycillin for the treatment of superficial pyoderma in dogs.     

Efficacy and tolerability of once-daily cephalexin in canine superficial pyoderma: an open controlled study

OBJECTIVES: The aims of this study were to evaluate the efficacy and tolerability of oral cephalexin given at 30 mg/kg once daily in dogs with superficial pyoderma and to compare them with those of oral cephalexin given at 15 mg/kg twice daily. METHODS: Twenty dogs with superficial pyoderma were treated with cephalexin at 30 to 60 mg/kg orally once daily (group A) and compared with 20 dogs treated at a dose of 15 to 30 mg/kg orally twice daily (group B). Dogs were treated until 14 days after clinical remission. Type and distribution of lesions, pruritus and general health status were assessed every 14 days using a numerical scale until 14 days after treatment discontinuation. Total scores for each evaluation day were compared between the two groups as well as time to obtain resolution and percentage of relapses. RESULTS: Resolution of superficial pyoderma was obtained in all dogs in 14 to 42 days (median 28 days for both groups), with no difference between groups. Six dogs experienced vomiting or diarrhoea but did not require discontinuation of the treatment. Only one dog (in group A) relapsed nine days after treatment discontinuation. CLINICAL SIGNIFICANCE: Once-daily cephalexin is as effective as twice-daily cephalexin in the treatment of canine superficial pyoderma.     

Efficacy of once-daily clindamycin hydrochloride in the treatment of superficial bacterial pyoderma in dogs.

Twenty-one dogs with canine superficial bacterial pyoderma were treated with clindamycin at a dosage of approximately 11 mg/kg body weight, q 24 hours, given orally for 14 to 42 days. All dogs were reexamined on days 14, 28, and, if necessary, 42 and given a clinical score of excellent (i.e., complete remission), good (i.e., primary lesions resolved but secondary lesions evident), fair (i.e., partial improvement but primary lesions still evident), or poor (i.e., no improvement or worsening of the lesions). A clinical score of excellent was obtained in 71.4% (15/21) of the dogs in this study within 14 to 28 days.     

The efficacy of a commercial shampoo and whirlpooling in the treatment of canine pruritus - a double-blinded, randomized, placebo-controlled study

Twenty‐two dogs with a history of at least 4 weeks pruritus were studied to determine the effect of whirlpool use on the efficacy of topical therapy with an antipruritic shampoo (Allermyl®, Virbac; Bad Oldesloe, Germany). Dogs in group 1 received initially topical therapy with conventional shampooing (2 mL shampoo per kilogram bodyweight) once weekly for 4 weeks. Dogs in group 2 received the same therapy using a whirlpool (Sanwhirl, Peter Aschauer GmbH; Gräfelfing, Germany). The treatments were crossed between the groups resulting in each dog in groups 1 and 2 receiving both therapies. Group 3 was the control group and was treated once weekly in the whirlpool without any shampoo during the 8 weeks of study. Prior to each therapy, dogs were evaluated by a clinician not aware of the type of treatment using a clinical scoring system (Canine Atopic Dermatitis Extent and Severity Index – CADESI). Owners evaluated the pruritus daily on a visual analogue scale. There was a significant difference in pruritus scores but not CADESI scores after therapy between the control treatment and the conventional shampoo therapy or shampoo treatment in the whirlpool. These results provide evidence for the short‐term benefit of shampoo therapy for canine pruritus.     

Masked, controlled study to investigate the efficacy of a Staphylococcus intermedius autogenous bacterin for the control of canine idiopathic recurrent superficial pyoderma

A masked, controlled study was designed to investigate the clinical efficacy of a staphylococcal autogenous bacterin for the control of canine idiopathic recurrent pyoderma (IRP). Ten dogs with at least three prior episodes of recurrent superficial pyoderma were recruited. All were screened and found to be free of ectoparasitic and fungal disease and failed to respond favourably to a dietary trial. Those exhibiting signs of pruritus responded completely to antibacterial therapy. Haematological and biochemical parameters were generally unremarkable and all dogs were euthyroid. Staphylococcus intermedius cultures from lesions were used to produce an autogenous bacterin for each animal. A numerical 'lesion score' was allocated and dogs were randomly divided into two groups of five (groups 1 and 2). Both groups received a 4-week course of antibiotic; group 1 also received concurrent s/c injections of bacterin, which continued until week 10. Group 2 received no additional therapy. All dogs were re-examined and rescored at weeks 5 and 10 and repeat blood samples were submitted at week 10 to screen for adverse effects. Comparison of scores at week 0 and week 5 (Mann-Whitney U-test) revealed no significant differences between the groups. At week 10, group 2 (control group) individual lesion scores were significantly higher compared with the group receiving bacterin (P < 0.05) and there was a significantly greater increase in the sum of the individual lesion scores for group 2 compared with group 1, from week 5 to week 10 (P < 0.05). No adverse reactions to bacterin therapy were detected. These results suggest that autogenous bacterins may provide an alternative, safe, effective method for the control of canine IRP. Further studies using larger groups of dogs and for a longer follow-up period are now warranted.     

Insertion sequence IS256 in canine pyoderma isolates of Staphylococcus pseudintermedius associated with antibiotic resistance

Staphylococcus pseudintermedius is the most frequent staphylococcal species isolated from canine pyoderma. The control of S. pseudintermedius infection is often difficult due to the expanded antimicrobial resistance phenotypes. Antibiotic resistance in staphylococcal pathogens is often associated to mobile genetic elements such as the insertion sequence IS256 that was first described as a part of the transposon Tn4001, which confers aminoglycoside resistance in Staphylococcus aureus and in Staphylococcus epidermidis. In this study a collection of 70 S. pseudintermedius isolates from canine pyoderma was used to investigate antimicrobial susceptibility to 15 antibiotics and the presence of IS256, not revealed in S. pseudintermedius yet. Antibiotic resistance profiling demonstrated that all S. pseudintermedius isolates had a multi-drug resistance phenotype, exhibiting simultaneous resistance to at least five antibiotics; indeed methicillin resistant S. pseudintermedius isolates were simultaneously resistant to at least nine antibiotics and all were also gentamicin resistant. PCR analyses revealed the presence of IS256 in 43/70 S. pseudintemedius isolates. The association between the presence of IS256 and the resistance was particularly significant for certain antibiotics: cefovecin, amikacin, gentamicin and oxacillin (χ(2)p-value<0.05). However, there was a striking result in frequency of strains resistant to gentamicin and oxacillin, suggesting a specific association between the presence of the IS256 element and the determinants for the resistance to these antibiotics. To the best of our knowledge, this is the first report showing the detection of IS256 in S. pseudintermedius isolates and its association with antibiotic resistance. Our findings suggest that S. pseudintermedius may acquire antibiotic resistance genes through mobile genetic elements which may play a predominant role in the dissemination of multi-drug resistance.     

Pradofloxacin in the treatment of canine deep pyoderma: a multicentred, blinded, randomized parallel trial

A multicentre, randomized, blinded study compared the efficacy of pradofloxacin with that of a combination of amoxycillin/clavulanic acid in the treatment of deep pyoderma in dogs. Dogs with clinical lesions of deep pyoderma and a positive bacterial culture were included in the study. At each visit, they were evaluated with lesion, pruritus and general condition scores. Dogs were treated either with pradofloxacin at 3 mg kg-1 once daily or with amoxycillin at 10 mg kg-1 and clavulanic acid at 2.5 mg kg-1 twice daily and evaluated weekly for 3 weeks and every 2 weeks thereafter until 2 weeks past clinical remission. Maximal treatment duration was 9 weeks, and maximal evaluation period was 11 weeks. Of the 56 dogs treated with pradofloxacin (group 1), 48 dogs (86%) achieved clinical remission, four dogs improved, four dogs did not respond and a recurrence of clinical signs was not seen in any patient after 11 weeks. Of the 51 dogs treated with amoxycillin/clavulanic acid (group 2), 37 dogs achieved clinical remission (73%), three dogs showed improvement, five dogs showed no response and in six dogs, clinical signs recurred within 2 weeks of cessation of therapy. These results indicate that pradofloxacin is an efficacious therapy comparable to amoxycillin/clavulanic acid for deep bacterial pyoderma in dogs.     

Pilot evaluation of the efficacy of shampoo treatment with ultrapure soft water for canine pruritus

Ultrapure soft water (UPSW) is water in which calcium and magnesium ions have been replaced with sodium ions using a cation‐exchange resin. We recently demonstrated that washing with soap and UPSW reduced the clinical severity of dermatitis and improved the skin barrier function in NC/NgaTnd mice, a murine model for human atopic dermatitis. The purpose of this pilot study was to evaluate the efficacy of shampoo treatment with UPSW for dogs with pruritus. Eleven dogs with pruritus were randomly assigned to two groups depending on whether they received weekly shampoo treatment with UPSW or tap water for 4 weeks. After a washout period, the treatment protocol was switched such that each dog received both treatments. The pre‐treatment and post‐treatment values of the following were compared: pruritus scores assessed by the owners; dermatitis scores recorded by an investigator; and transepidermal water loss (TEWL). Shampoo treatment with UPSW significantly decreased pruritus and dermatitis scores in the dogs, whereas shampoo treatment with tap water did not. In addition, shampoo treatment with UPSW, but not with tap water, significantly reduced TEWL in the dogs. Adverse events due to the treatment were not observed in the dogs. Furthermore, we found that topical application of UPSW for barrier‐disrupted skin caused by tape stripping in healthy dogs decreased TEWL more rapidly than topical application of tap water. Our findings suggest that shampoo treatment with UPSW promotes skin barrier recovery and thus could be considered as a possible therapeutic option in the management of pruritus and dermatitis in dogs.     

Aspects of the humoral immune response to Staphylococcus intermedius in dogs with superficial pyoderma,deep pyoderma and anal furunculosis

Bacterial infection (pyoderma) of the canine skin is largely caused by Staphylococcus intermedius and may be a superficial or deep infection. Pyoderma may be a primary, idiopathic disease or secondary to a range of other dermatological disorders. In this study, the serum concentrations of IgG, IgA, antistaphylococcal IgG and antistaphylococcal IgA were measured by ELISA in normal dogs (n = 22), dogs with idiopathic deep pyoderma (n = 22), atopic dermatitis and superficial pyoderma (n = 24), atopic dermatitis without pyoderma (n = 25), flea bite dermatitis with superficial pyoderma (n = 8), pustular demodicosis (n = 8) and German shepherd dogs with anal furunculosis (n = 28). The serum IgG was significantly increased in dogs with atopy and superficial pyoderma (p < 0.001), and lower than normal in dogs with idiopathic deep pyoderma (p < 0.015). The concentration of serum IgA was significantly lower than normal in dogs with atopy uncomplicated by pyoderma (p < 0.015). The concentration of antistaphylococcal IgG in all clinical sera was significantly elevated (p < 0.001) when compared to normal dogs but concentrations of antistaphylococcal IgA were no greater than in normal dogs. Western blotting analysis for determination of the specificity of serum IgG antistaphylococcal antibody revealed that there were nine major epitopes. Discriminant analysis demonstrated that particular combinations of these epitopes were recognised more frequently by sera from dogs in different clinical groups.     

Investigation of the clinical efficacy of 0.2% topical stannous fluoride for the treatment of canine superficial pyoderma: a prospective,randomized, double‐blinded,placebo‐controlled trial

Stannous fluoride (SF) is an antibacterial compound that has been successfully used to treat gingivitis in people and dogs, and cutaneous bacterial infections in horses. The purpose of this prospective, double‐blinded, placebo‐controlled clinical trial was to investigate the efficacy of 0.2% SF spray (BacDerm^®; Emerald 3 Enterprises Inc., Camdenton, MO, USA) for the treatment of canine superficial pyoderma. Twenty‐six privately owned dogs with bacterial skin infections diagnosed on clinical signs, cytology and aerobic culture were enrolled. Dogs were randomly assigned to vehicle only or active ingredient treatment groups. The product was applied topically to affected areas once daily for 28 days, with assessments at days 0, 14, 28 and 42. Clinical and cytological evaluations were performed by the same investigators at each visit. Owners scored the improvement of hair coat, odour, pruritus and overall improvement at each recheck. Linear mixed models showed significant effects of treatment (P < 0.0001) and time (P = 0.0037) for investigator’s scores, and a significant time effect for owners’ haircoat (P = 0.0077) and odour (P = 0.0170) improvement scores. Dogs in both placebo and SF groups showed some improvement over time, and the investigator’s scores on days 0 and 28 were not significantly different between groups for both (t‐test P > 0.05). Spearman’s rho correlation coefficients revealed a significant negative correlation between investigator’s scores and all categories of owners’ assessment scores in dogs of both groups. Although some dogs improved on SF, this study does not support the use of 0.2% SF as sole therapy for canine superficial pyoderma.     

Risk factors associated with the antimicrobial resistance of staphylococci in canine pyoderma

This study reports the susceptibility to antimicrobial agents of staphylococci (n=105) isolated from dogs, and the factors associated with this resistance. The study animals were 23 healthy dogs (group A), 24 with first-time pyoderma (group B), and 27 with recurrent pyoderma that had undergone long-term antibiotic treatment (group C). Staphylococci were more commonly isolated from the pyoderma-affected than the healthy dogs (p<0.0001). Some 78% of the isolates were resistant to at least one antimicrobial agent. Resistance to amoxicillin-clavulanate, cephalosporins (OR 4.29, 95% CI [1.15, 16.3] respectively), enrofloxacin (OR 9.47, 95% CI [1.53, 58.5]) and ciprofloxacin (OR 79.7 95% CI [3.26, 1947.4]) was more common among group C isolates. Some 32% of all the isolates were multiresistant (MR) and 10.4% were methicillin-resistant (MRS). The probability of isolating MRS staphylococci in group C increased by a factor of four (95% CI [1.18, 17.9]) compared to A plus B. Multi-resistant (MR) isolates were obtained more commonly from urban than rural dogs (OR 3.79, 95% CI [1.09, 13.17]). All the MRS staphylococci encountered were obtained from urban dogs and more commonly from male dogs (p=0.07). This study shows that dogs bred in urban habitat, with a history of antibiotic therapy in the past year represents significant risk of being carriers of isolates resistant to methicillin (MRS) and other antimicrobials. These factors should be considered before applying an antimicrobial treatment in veterinary clinics.     

Clinical efficacy and safety of cefovecin in the treatment of canine pyoderma and wound infections

OBJECTIVES: To determine the efficacy and safety of cefovecin in the treatment of bacterial skin infections in dogs. METHOD: Dogs with superficial or deep pyoderma or wounds/abscesses were enrolled in three separate studies. Dogs (354) were randomised to treatment and received either cefovecin administered by subcutaneous injection at 14 day intervals, as clinically necessary, or amoxicillin/clavulanic acid as oral tablets twice daily for 14 days. Courses of treatment were repeated at 14 day intervals up to a total of four courses. Clinicians responsible for assessing lesions were masked to treatment allocation. Only animals where the presence of a pretreatment bacterial pathogen was confirmed were included in the analysis of efficacy. Cases were evaluated for clinical efficacy at 28 days after initiation of the final course of treatment. Clinical efficacy was assessed by scoring the clinical signs typical of skin infections. RESULTS: Cefovecin demonstrated statistical non-inferiority compared with amoxicillin/clavulanic acid for all three clinical diagnoses; for cefovecin, up to 96.9 per cent efficacy was observed versus 92.5 per cent for amoxicillin/clavulanic acid. CLINICAL SIGNIFICANCE: Cefovecin was shown to be as effective as amoxicillin/clavulanic acid administered orally in the treatment of bacterial skin infections in dogs. Cefovecin offers the additional benefit of eliminating owner non-compliance.     

P-6 Double-blinded comparative study of the efficacy of azithromycin and cephalexin in canine pyoderma

Bacterial pyoderma is one of the most frequent skin diseases in dogs. Recurrent pyoderma is often secondary to an underlying skin disease, but no epidemiological study has been published on the subject to the authors' knowledge. This study was designed to prospectively evaluate the causes responsible for recurrent pyoderma in dogs. Dogs presenting with a history of more than three episodes of skin infection in the last year were included in the study. For each case, epidemiological and clinical data were collected. Pyoderma was confirmed by the clinical signs, the demonstration of bacteria on microscopic examination of cytological smears and a positive culture. Each animal was treated with an appropriate course of antibiotics until resolution of signs of pyoderma. Depending upon the presence of pruritus, appropriate diagnostic tests were performed: skin scrapings, acaricidal trial, flea treatment, elimination diet, intradermal testing, biopsies, endocrinological tests, leishmaniasis and ehrlichiosis serology, antinuclear antibody testing. Thirty dogs (14 males and 16 females) of 19 different breeds, aged from 1 to 12 years (mean 4.9 years) were included. Diagnosis was folliculitis (44%), folliculitis and furunculosis (20%), furunculosis (20%), cellulitis (10%). Staphylococcus intermedius was isolated in 97% of cases. The following underlying diseases were identified: atopic dermatitis (60%), food allergy (7%), flea allergy (7%), hypothyroidism (7%), hyperestrogenism (4%), demodicosis (4%), and zinc-responsive dermatosis (4%). In two dogs, no underlying cause could be identified. Atopic dermatitis is the most common disease associated with recurrent pyoderma in dogs.
Funding: Pfizer Animal Health.