Comparison of Aerobic Bacterial Culture Among Four Veterinary Microbiology Laboratories from Dogs with Superficial Pyoderma

Bacterial culture and susceptibility are widely used in veterinary medicine to determine the specific bacteria causing infection as well as aid in appropriate antimicrobial selection. Previous studies have shown variable results with culture and susceptibility depending on the laboratory and methodology used. Samples from dogs with superficial pyoderma were obtained to make a homogeneous solution of bacteria. Sample acquisition from this solution was randomized and submitted to four veterinary laboratories for microbial identification and sensitivity. There was fair agreement among the laboratories in identification of a Staphylococcus spp. as well as fair agreement among the laboratories on the same Staphylococcus sp. Very good agreement was noted on identification of methicillin-resistant Staphylococcus spp. Additionally, good to very good agreement was noted on all antimicrobials that were tested across all four laboratories. A difference in turnaround time for sample processing was observed between the laboratories in the present study. Overall, there was mild variability among the laboratory results in this study.

Retrospective evaluation of ceruminous gland tumors confined to the external ear canal of dogs and cats treated with biopsy and CO2 laser ablation

BACKGROUND

Treatments currently available for ceruminous gland tumors include surgery and radiation therapy, which come with high financial costs and frequent complication and recurrence rates.

HYPOTHESIS

To evaluate the treatment, response, complication, and recurrence of ceruminous gland tumors confirmed with biopsy and ablated using CO2 laser.

METHODS

Retrospective review of medical records from Iowa State University and the University of Illinois between January 1, 2016 and December 31, 2021. Electronic medical records were evaluated for a histopathologically confirmed ceruminous gland tumor via video-otoscopic aided biopsy and subsequent CO2 laser ablation. Signalment, tumor type, size, location within the ear canal, length of time tumor was present before presentation, advanced imaging, and follow-up including recurrence were assessed.

RESULTS

Fourteen ceruminous gland adenomas (4 dogs, 10 cats) and 12 ceruminous gland adenocarcinomas (7 dogs, 5 cats) were identified. Bacterial otitis externa was present in 4/26 (15%) animals. Recurrence was identified in 1/14 (7%) ceruminous gland adenomas and 1/12 (8%) ceruminous gland adenocarcinomas.

CONCLUSIONS AND CLINICAL IMPORTANCE

Video-otoscopic aided biopsy and CO2 laser ablation of ceruminous gland tumors in dogs and cats is a viable treatment option with low recurrence and complication rates with CO2 laser ablation.

Trichophyton mentagrophytes complex: A retrospective study of 64 dogs from the Central United States (1997-2020)

BACKGROUND

There are limited clinical studies evaluating the Trichophyton mentagrophytes complex, with most reports confined to small case studies. Additionally, the studies are dated and provide limited information on response to newer or currently available therapies.

HYPOTHESIS/OBJECTIVES

The aim of the study was to determine if there is a breed prevalence, lesion distribution and seasonality associated with the T. mentagrophytes complex for dogs evaluated in the central United States. An additional aim of the study was to evaluate response to therapies because there are minimal data available on clinical response with newer systemic antifungal drugs.

ANIMALS

A total of 64 canine medical records were evaluated that had a previous diagnosis of T. mentagrophytes complex infection.

MATERIALS AND METHODS

A retrospective study of medical records to evaluate signalment, time of onset of clinical signs, clinical presentation and therapeutic management.

RESULTS

A higher incidence of T. mentagrophytes complex infection was observed in the American Kennel Club (AKC) Sporting group (43%) and Terrier group (20%). A seasonal influence was noted, with the onset of clinical signs being highest in October. Lesions most often affected the muzzle (48%), followed by the head excluding the pinnae (21%). Ketoconazole, itraconazole and terbinafine appeared equivalent as systemic therapeutic options to treat T. mentagrophytes complex infections.

CONCLUSIONS AND CLINICAL RELEVANCE

This study identified patterns in breeds, seasonality and lesion distribution for the T. mentagrophytes complex in dogs from the central United States. Additionally, the study found several reasonable and reliable treatment options for systemic therapy.

Characterization of recessed vulvas in dogs

OBJECTIVE

To determine the prevalence of vulvar recession in a large population of dogs and to compare the reproductive and physical differences between dogs with and without recessed vulvas.

ANIMALS

250 female dogs presenting to a tertiary referral institution.

PROCEDURES

Female dogs > 6 months of age presenting to a tertiary referral institution were enrolled. At enrollment, a full medical history was obtained with particular emphasis on the presence of lower urinary tract (LUT) disease in the 3 months prior to presentation. All dogs underwent a full physical examination including perivulvar cytologic examination and scoring of the degree of perivulvar skin coverage on the basis of an 8-point scale. Dogs with scores of ≥ 7 were classified as having recessed vulvas. When available, urinalysis data were also included.

RESULTS

Recessed vulvas were identified in 36 of 250 (14%) dogs. Dogs with recessed vulvas had significantly higher body condition scores and body weights than unaffected dogs. In addition, recessed vulvas were more common in spayed than sexually intact dogs. Dogs spayed at ≤ 1 year of age were almost 3 times as likely to have vulvar recession, compared with dogs spayed at > 1 year of age. No significant difference was identified between affected and unaffected dogs with respect to the prevalence of LUT signs, urinary tract infections, or perivulvar dermatitis.

CONCLUSIONS AND CLINICAL RELEVANCE

Although recessed vulvas were relatively common in dogs, they did not appear to be associated with an increased risk of LUT disease or perivulvar dermatitis.

Chemical and microbiological stability of diluted ceftazidime in three different solutions under three storage temperatures over a 28 day period

BACKGROUND

Ceftazidime (CAZ) solutions are being used based on anecdotal reports for otitis externa complicated by multidrug-resistant Pseudomonas aeruginosa (MDR PA). The chemical and microbiological stability of these proposed compounded solutions have not been evaluated, and likely are affected by the diluent and storage duration or temperature.

HYPOTHESIS/OBJECTIVES

Compounded CAZ solutions would show variable degradation dependent on diluent, time and temperature. The antimicrobial activity of the solutions would reflect changes in concentration and not alterations to the chemical compound.

METHODS AND MATERIALS

Ceftazidime was compounded with 100 mL 0.9% sodium chloride (NA+CAZ), 118 mL Triz-EDTA Aqueous flush (TE+CAZ) and 125 mL Douxo Micellar Solution (MI+CAZ). Aliquots of the solutions were stored at 25ºC, 4ºC and -20ºC for 28 days. High-performance liquid chromatography was used to analyse CAZ recovery from compounded solutions at weekly intervals. A modified broth dilution technique was utilised to assess minimum inhibitory concentration (MIC) to monitor antimicrobial activity against a reference PA strain.

RESULTS

Temperature, duration of storage and diluent each had independent effects on the chemical stability of CAZ. CAZ concentrations decreased over time as well as with increased temperature. NA+CAZ solutions exhibited the least degradation compared to the other solutions. The MIC for PA was most consistent for NA+CAZ solutions regardless of storage temperature and duration of storage.

CONCLUSIONS AND CLINICAL IMPORTANCE

Chemical and microbiological stability of compounded CAZ solutions varied by diluent, storage temperature and duration of storage. Dilution in NA resulted in the lowest variation in stability over 28 days when stored at refrigerated or frozen temperatures compared to other diluents.

Diagnosis and clinical management of auricular chondritis in a dog presenting for evaluation of severe pain

BACKGROUND

The aetiology and appropriate treatment for auricular chondritis in the dog are currently unclear. This report describes a unique presentation and successful treatment of a dog with auricular chondritis.

CLINICAL SUMMARY

A 12-year-old, female spayed, Labrador retriever dog was presented for severe pain thought to be neurological in origin. The pain was located to the right pinna and two punch biopsies were acquired and evaluated, revealing lymphoplasmacytic to pyogranulomatous inflammation involving the auricular cartilage with no infectious agents. Treatment with systemic oral prednisone resulted in resolution of clinical signs within four weeks of initiation of treatment. The dog remained free of clinical signs for six months following discontinuation of treatment before being euthanized for an unrelated reason.

CONCLUSIONS

Further evaluation of canine auricular chondritis is needed, yet pain may be a prominent finding; monotherapy with systemic prednisone may provide quick and complete resolution of clinical sysmptoms.

Afoxolaner as a Treatment for a Novel Sarcoptes scabiei Infestation in a Juvenile Potbelly Pig

A 2 months old female Vietnamese potbellied pig presented to a veterinary teaching hospital with a referring complaint of pruritus. A human caretaker of the pig had recently been diagnosed with a Sarcoptes spp. dermatitis. Microscopic examination of the skin scrape samples and BLAST analysis confirmed the species of the mite as most closely related to Sarcoptes scabiei var. canis (AY493391). The pig was treated with afoxolaner as previous treatment with ivermectin was not efficacious. Recheck examinations and follow up revealed the pig to be non-pruritic and resolving. Afoxolaner may be a therapeutic option when treating Sarcoptes spp. infections in companion pigs.

Clinicopathologic, hemodynamic, and echocardiographic effects of short-term oral administration of anti-inflammatory doses of prednisolone to systemically normal cats

OBJECTIVE

To evaluate the clinicopathologic, hemodynamic, and echocardiographic effects of short-term administration of anti-inflammatory dosages of prednisolone to systemically normal cats.

ANIMALS

10 cats with allergic dermatitis and 10 healthy control cats.

PROCEDURES

Cats with allergic dermatitis were randomly allocated to 2 groups and received 2 dosages of prednisolone (1 and 2 mg/kg/d, PO, for 7 days) in a crossover design followed by 9-day tapering and 14-day washout periods. Each prednisolone-treated cat was matched to a healthy control cat on the basis of sex, neuter status, age (± 1 year), and body weight (± 10%). Control cats received no treatment during the 35-day observation period. Clinicopathologic, echocardiographic, and hemodynamic variables were measured at baseline (day 0) and predetermined times during and after prednisolone administration and compared within and between the 2 treatment groups.

RESULTS

Prednisolone-treated cats had expected clinicopathologic alterations (mild increases in neutrophil and monocyte counts and serum concentrations of albumin, cholesterol, and triglycerides) but systolic arterial blood pressure; blood glucose, serum potassium, and cardiac biomarker concentrations; urinary sodium excretion; and echocardiographic variables did not differ significantly from baseline at any time. Statistically significant, albeit clinically irrelevant, increases in blood glucose and N-terminal pro-B-type natriuretic peptide concentrations were observed between baseline and the prednisolone pharmacokinetic steady state (7 days after initiation) only when the 2-mg/kg dosage was administered.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated short-term oral administration of anti-inflammatory dosages of prednisolone did not cause relevant hemodynamic, echocardiographic, or diabetogenic effects in systemically normal cats with allergic dermatitis.

Relative Oral Bioavailability of Two Amoxicillin-Clavulanic Acid Formulations in Healthy Dogs: A Pilot Study

The use of human generic amoxicillin-clavulanic acid formulations in veterinary medicine is currently lacking supportive evidence. This pilot study was conducted to determine preliminary pharmacokinetic parameters and relative oral bioavailability of a human generic and veterinary proprietary 4:1 amoxicillin-clavulanic acid formulation in healthy dogs to evaluate whether drug exposure was similar and to determine if further comparative investigation is warranted. Each dog received a single oral dose of each formulation containing 500:125 mg of amoxicillin-clavulanic acid at two separate instances with a 2 wk washout period between product administration. Following drug administration, blood was collected at fixed times over 24 hr to measure plasma amoxicillin and clavulanic acid concentrations using liquid chromatography-mass spectrometry. There were no statistically significant differences between pharmacokinetic parameters of either formulation. Clavulanic acid showed greater between-dog variation in drug exposure between formulations compared with amoxicillin and was also observed to be more variable within the veterinary proprietary formulation. The average relative oral bioavailability was 98.2% (23.6% coefficient of variation) for amoxicillin and 152.6% (64.3% coefficient of variation) for clavulanic acid between formulations. This pilot investigation supports the need for further bioequivalence studies regarding these formulations before commenting on product interchangeability.

Evaluation of compounded aqueous milbemycin oxime: issues with formulation potency and reproducibility

OBJECTIVES

To determine the potency and reproducibility of milbemycin oxime when compounded as an aqueous suspension (20 mg/mL).

MATERIALS AND METHODS

Preparation choice reflected current prescribing practices. Samples were acquired by prescription from two national veterinary compounding pharmacies at three time points. Two different storage conditions were evaluated and sampled at four time points from the order date (day 7, 14, 21 and 28). Milbemycin oxime recovery was performed by solid-phase extraction and concentration strength measured via high-performance liquid chromatography.

RESULTS

The average concentration on day 7 for Pharmacy A samples was 16.29 mg/mL [confidence interval (CI): 15.66 to 16.92] with a coefficient of variation (CV) = 11%, while for Pharmacy B it was 20.46 mg/mL (CI: 19.83 to 21.08) with CV = 22%. The mean decrease in concentration over 28 days for Pharmacy A was 22% (CI: 9% to 34%) while Pharmacy B was 18% (CI: 2% to 35%).

CLINICAL SIGNIFICANCE

The compounded milbemycin oxime suspensions evaluated in this study deviated by more than 10% from their labelled strength in five of the six lots. Clinical efficacy of compounded milbemycin oxime suspensions remains unknown and the use of these products should be discouraged at this time.

Canine Alopecia Secondary to Human Topical Hormone Replacement Therapy in Six Dogs

Alopecia is a common presenting complaint in veterinary medicine and is known to occur secondary to numerous primary conditions. In this report, six unrelated dogs from three households were subsequently determined to have developed alopecia as a result of accidental transdermal exposure to their owners' topical hormone replacement therapy (THRT). All cases presented with alopecia ranging in duration from 2 mo to 2.5 yr. All dogs demonstrated alopecia affecting the ventral neck, thoracic and abdominal surfaces, proximal lateral extremities, and lateral trunk. At the time of initial presentation, five of six dogs were also noted to have physical exam findings suggestive of feminization. In all cases, serum total thyroxine was within normal reference range. Affected skin was biopsied in five dogs, and all samples demonstrated four similar histological characteristics: basal melanosis, epidermal and infundibular follicular hyperkeratosis, kenogen hair follicles, and small sebaceous glands. All dogs had elevated baseline estradiol levels, and four dogs had concurrent elevations of baseline progesterone. Average time to onset of clinical signs in those dogs was 5.5 mo after the owners started THRT. Following discontinuation of THRT by the owners, all dogs had complete resolution of their clinical signs by 5.5 mo.

Comparison of once-daily versus twice-weekly terbinafine administration for the treatment of canine Malassezia dermatitis - a pilot study

BACKGROUND

Terbinafine, an allylamine antifungal, is used in pulsatile dose regimens for superficial mycoses in human medicine.

OBJECTIVES

To compare the clinical efficacy of twice-weekly versus once-daily terbinafine administration to determine whether preliminary proof-of-concept evidence exists for pulsatile administration of terbinafine in the treatment of canine Malassezia dermatitis and to determine whether twice-weekly treatment results in fewer clinical and owner-perceived adverse events.

ANIMALS

Twenty client-owned dogs with Malassezia dermatitis.

METHODS

In this randomized, single-blinded clinical trial, dogs were randomly assigned to receive terbinafine (30 mg/kg) either once daily for 21 days (n = 10) or once daily on two consecutive days per week for six doses (n = 10). On day 0 and day 21, a mean yeast count was calculated from eight anatomical locations via adhesive tape-strip cytology, clinical lesion scores were assigned to the same locations, and owners assessed pruritus using a visual analog scale.

RESULTS

There was no significant difference between treatment groups with respect to the reduction in mean yeast count (P = 0.343) and clinical lesion scores (P = 0.887). Pruritus measured by visual analog scale was significantly decreased in the twice-weekly treatment group compared with the daily treatment group (P = 0.047). Seven of 20 dogs had a clinically measurable or owner-reported adverse event during treatment that included gastrointestinal disturbances, excessive panting and elevated hepatic enzymes, with no significant difference noted between treatment groups.

CONCLUSIONS AND CLINICAL IMPORTANCE

This pilot study indicates that twice-weekly terbinafine administration may be an effective alternative treatment for canine Malassezia dermatitis and merits further investigation.