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.

Putative antimicrobial-associated phototoxicity in three dogs.

This case series describes putative doxycycline phototoxicity in three dogs, with one also undergoing a possible sulfamethoxazole phototoxic reaction.

Cette série de cas décrit la possible phototoxicité de la doxycycline chez trois chiens, à laquelle s'ajouterait une possible réaction phototoxique au sulfaméthoxazole chez l'un des chiens.

Está serie de casos describe una posible reacción de fototoxicidad en tres perros, junto con otro también sufriendo una posible reacción fototóxica por administración de sulfametoxazol.

Esta série de casos descreve a fototoxicidade putativa da doxiciclina em três cães, sendo que um também passou por uma possível reação de fototoxicidade por sulfametoxazol.

Evaluation for Postoperative Infections Following Cutaneous Punch Biopsies in Dogs and Cats: 154 Cases (2013-2018).

Antimicrobial stewardship is becoming more important every day with increasing bacterial resistance and limitations on antibiotics. Prophylactic antibiotics are not necessary with all procedures, which has been shown previously with a variety of human and veterinary surgeries. Medical records were retrospectively evaluated for cases who had a cutaneous punch biopsy performed between 2013 and 2018 including the following information: species, signalment, concurrent diseases, concurrent medications, location of biopsy, histopathologic diagnosis, and bacterial infections postoperatively. The prevalence of secondary infections, due to punch biopsies in all animals, was 1.9% and further divided into 2.3% (3/128) of dogs and 0% (0/26) of cats. It was determined that the relative risk of developing complications from punch biopsy was 0.06 (0.01-0.93) when diagnosing a dermatologic disease versus a cutaneous mass (neoplastic and nonneoplastic), which was statistically significant. The risk increased 2.16 (0.16-59.91) times if the biopsy site was the trunk, which includes the neck, thorax, and abdomen. These results indicate that in veterinary medicine, postoperative complications are uncommon with cutaneous punch biopsies. The administration of prophylactic antibiotics in dogs and cats is unnecessary when performing a punch biopsy when there is no infection present at the time of biopsy.

Survey of dermatophytes in stray dogs and cats with and without skin lesions in Puerto Rico and confirmed with MALDI-TOF MS.

Dermatophytosis is a common and highly contagious zoonotic skin disease in companion animals. This disease is a major concern in geographical areas that contain large numbers of stray animal populations. Numerous surveys on dermatophytosis among stray animal populations worldwide range between 27% to 50%. In recent years, the US territory of Puerto Rico was impacted by several natural disasters such as hurricanes, which has led to a large increase of abandonment cases and an increase in the stray animal population. Due to this, large low-cost spay/neuter clinics and trap-neuter-release programs have become a more common practice on the island. During these events, veterinary staff are exposed to multiple animals with no health history, and therefore, zoonotic diseases are of concern. The aim of this study was to provide information regarding the presence of dermatophyte species in symptomatic and asymptomatic stray dogs and cats in a region of Puerto Rico. Hair samples were collected from 99 stray animals with and without dermatological clinical signs. The hair samples were cultured on plates containing rapid sporulation medium and dermatophyte test medium. All cultures were evaluated microscopically to confirm the presence of dermatophytes. Then, all dermatophytes were further evaluated with MALDI-TOF MS to compare both diagnostic tests. A total of 19 animals (19%) were positive for dermatophyte growth. Of these animals, 18/19 were infected with M. canis and 1/19 with Trichophyton spp. Animals with clinical lesions were positive only 13.5% of the time compared to asymptomatic animals, who were positive in 36% of the sample population. All 19 dermatophytes (100%) diagnosed with microscopic evaluation were confirmed with MALDI-TOF MS. Our results indicate that there is a prevalence of 19% of dermatophytosis among the stray dog and cat population of the southeastern coast of the island.

Effect of light exposure on growth rate of veterinary clinical dermatophyte isolates.

BACKGROUND: Veterinary textbooks and literature suggest that exposure to light is inhibitory to growth of clinical dermatophyte isolates. HYPOTHESIS/OBJECTIVES: We hypothesized that this idea was derived from experiments that examined the effect of high doses of ultraviolet and visible light exposure on dermatophyte growth, and that exposure to typical room lighting would not adversely affect dermatophyte growth rate. METHODS AND MATERIALS: Isolates of common veterinary dermatophytes (three each of Microsporum canis, Nannizia gypsea and Trichophyton benhamiae) were exposed to typical fluorescent room lighting, incubated in a closed drawer, or exposed at close range to fluorescent wide-spectrum light. Dermatophytes were grown on Sabouraud Dextrose Agar (SAB) and Dermatophyte Test Medium (DTM). Colony diameter was measured and growth rate (expressed as colony diameter increase mm/day) calculated at the linear portion of the culture growth curve. Statistical analyses compared growth rates across the various incubation conditions and among dermatophyte isolates. RESULTS: There was little difference in growth rate between cultures incubated under typical fluorescent room lighting and those placed in the dark. Exposure to the close-range light increased growth rate as a consequence of the elevated incubation temperature created by the lamp. Significant differences in growth rate were noted among strains of the same dermatophyte species. Dermatophytes grew more rapidly on SAB than DTM agar. CONCLUSIONS AND CLINICAL RELEVANCE: Exposure to typical lighting conditions in a clinical environment does not inhibit growth of dermatophyte colonies. Veterinary clinicians may conduct routine dermatophyte cultures without incubating them in the dark.

The effect of topical lidocaine on intradermal testing in atopic dogs.

BACKGROUND: Intradermal testing (IDT) most often requires sedation. Topical lidocaine offers an adjunct or alternative to sedation. HYPOTHESIS/OBJECTIVES: We hypothesized that topical lidocaine would significantly reduce reactions to intradermal injections and that atopic dogs treated with topical lidocaine would have similar results with IDT to atopic dogs tested without topical lidocaine. ANIMALS: Fifteen client-owned atopic dogs. METHODS: In Part I, a 5% lidocaine patch, 5% lidocaine cream and a control with no active ingredients were compared. The lowest pain score during intradermal injection was established in six atopic dogs. Fifteen atopic dogs were enrolled in Part II, and lidocaine cream (found to be most effective in Part 1) was applied randomly to a single side of the thorax. An IDT was performed on each side of the chest. Subjective and objective scores of the control and lidocaine treatment sides were compared 15 and 30 min post-injection. RESULTS: The 5% lidocaine cream had the greatest reduction in pain score associated with intradermal injection. There were no significant differences in mean wheal diameter for any evaluated allergen at any time point between the control and lidocaine-treated sides. There was high agreement between the two groups when assessing the subjective score for all but one allergen. CONCLUSIONS AND CLINICAL IMPORTANCE: Topical lidocaine may be used as adjunctive analgesia during IDT with caution in interpretation of subjective house dust scoring. Lidocaine cream appeared to reduce pain score and may allow reduction in concurrent sedation.

Prophage-Mediated Disruption of Genetic Competence in Staphylococcus pseudintermedius.

Methicillin-resistant Staphylococcus pseudintermedius (MRSP) is a major cause of soft tissue infections in dogs and occasionally infects humans. Hypervirulent multidrug-resistant (MDR) MRSP clones have emerged globally. The sequence types ST71 and ST68, the major epidemic clones of Europe and North America, respectively, have spread to other regions. The genetic factors underlying the success of these clones have not been investigated thoroughly. Here, we performed a comprehensive genomic analysis of 371 S. pseudintermedius isolates to dissect the differences between major clonal lineages. We show that the prevalence of genes associated with antibiotic resistance, virulence, prophages, restriction-modification (RM), and CRISPR/Cas systems differs significantly among MRSP clones. The isolates with GyrA+GrlA mutations, conferring fluoroquinolone resistance, carry more of these genes than those without GyrA+GrlA mutations. ST71 and ST68 clones carry lineage-specific prophages with genes that are likely associated with their increased fitness and virulence. We have discovered that a prophage, SpST71A, is inserted within the comGA gene of the late competence operon comG in the ST71 lineage. A functional comG is essential for natural genetic competence, which is one of the major modes of horizontal gene transfer (HGT) in bacteria. The RM and CRISPR/Cas systems, both major genetic barriers to HGT, are also lineage specific. Clones harboring CRISPR/Cas or a prophage-disrupted comG exhibited less genetic diversity and lower rates of recombination than clones lacking these systems. After Listeria monocytogenes, this is the second example of prophage-mediated competence disruption reported in any bacteria. These findings are important for understanding the evolution and clonal expansion of MDR MRSP clones.IMPORTANCE Staphylococcus pseudintermedius is a bacterium responsible for clinically important infections in dogs and can infect humans. In this study, we performed genomic analysis of 371 S. pseudintermedius isolates to understand the evolution of antibiotic resistance and virulence in this organism. The analysis covered significant reported clones, including ST71 and ST68, the major epidemic clones of Europe and North America, respectively. We show that the prevalence of genes associated with antibiotic resistance, virulence, prophages, and horizontal gene transfer differs among clones. ST71 and ST68 carry prophages with novel virulence and antibiotic resistance genes. Importantly, site-specific integration of a prophage, SpST71A, has led to the disruption of the genetic competence operon comG in ST71 clone. A functional comG is essential for the natural uptake of foreign DNA and thus plays an important role in the evolution of bacteria. This study provides insight into the emergence and evolution of antibiotic resistance and virulence in S. pseudintermedius, which may help in efforts to combat this pathogen.

Evaluation of hair follicle parameters using TrichoScale Pro© in healthy dogs: a pilot study.

BACKGROUND: Trichoscopy, in combination with image analysis software, is a readily available, efficient diagnostic tool for assessing hair follicle parameters of people in vivo. Systems designed for use in human dermatology must be evaluated and validated with animal skin/hair before they can be used for veterinary applications. OBJECTIVES: To evaluate the use of a commercial software package for image analysis of canine hair follicles and to define hair follicle parameters. ANIMALS: Thirteen client-owned healthy dogs. METHODS: Trichoscopic images at x20 magnification were obtained from three shaved body sites (left dorsal head, left thorax, left flank) over a five day period, then analyzed by the software. RESULTS: The image analysis software was able to identify microscopic changes in hair length on a daily basis, calculating a mean hair growth rate of 0.065 mm/day. Each of the three body sites had consistent hair growth rates across all days. Anagen and telogen percentages were consistent at each body site by Day 2 (48 h post-clipping). Data for mean hair thickness, and primary and secondary hair percentages also are reported. CONCLUSIONS: Although it provides less useful data for canine hair coats than for human scalp hair, the system evaluated provides an easy, noninvasive, rapid means for assessing several important canine hair follicle parameters: daily hair growth rates, anagen and telogen percentages, primary and secondary hair percentages, and mean hair thickness. This diagnostic tool could serve to establish breed-specific hair coat standards, evaluating hair follicle changes in various canine alopecic conditions and monitoring coat-promoting treatments in dogs.

Intralaboratory Reliability and Variability for Allergen-Specific Immunoglobulin Type E Serology Testing.

Atopic dermatitis is a very common condition affecting dogs and often managed with allergen-specific immunotherapy, which requires accurate identification of causative allergens. Serology testing is used commonly. Serum was collected from 35 atopic dogs and separated into three samples each (1, 2, and 3). Samples 1 and 2 were sent to IDEXX Laboratories the same day; sample 3 was stored at -80°C and submitted ∼30 days later. Specific immunoglobulin type E reactivity to various allergens were determined using monoclonal anti-canine enzyme-linked immunosorbent assay (ELISA) and expressed as ELISA absorbance units. Percent difference ranged from 14.30 to 127.34% for samples 1 and 2. These values increased when comparing samples a month apart (21.78 to 129.65%). Between samples 1 and 2, for each allergen there were differences in interpretation 15.18% of the time; 32 of 35 dogs (91.4%) had at least one allergen with a different interpretation. Comparing sample 3 and the average of samples 1 and 2, differences in interpretation increased to 22.32%; all dogs had at least one allergen that was interpreted differently. These differences in interpretation can alter immunotherapy. Overall, results show the need for better reliability for allergen-specific immunoglobulin type E serology testing using monoclonal anti-canine ELISA.

Urticaria pigmentosa-like skin disease in a domestic shorthair cat.

CASE SUMMARY: A 14-month-old castrated male domestic shorthair cat presented with an 8 month history of severe pruritus, alopecia, papules and excoriations. Initial evaluation and treatment prior to referral included skin scrape, cytology, two strict food trials, dermatophyte culture, and bacterial culture and sensitivity, as well as antibiotic therapy, empiric treatment for mites, steroids and ciclosporin A (Atopica; Elanco). The cat was referred to the Dermatology and Otology Clinic at the University of Illinois Veterinary Teaching Hospital for further diagnostics and treatment. Skin scrapes were unremarkable. Cytology showed rare bacteria and moderate neutrophils. The cat was given an injection of triamcinolone acetonide, which was ineffective. Oclacitinib (Apoquel; Zoetis) was given for 4 weeks with no improvement. A skin biopsy was performed, and histopathology showed large numbers of well-differentiated monomorphic mast cells with fewer eosinophils that diffusely infiltrated the superficial dermis, supportive of urticaria pigmentosa. Oral dexamethasone and cetirizine hydrochloride were initiated, and the cat responded favorably. At the time of writing, the cat continues to do well on cetirizine hydrochloride with only intermittent tapering courses of dexamethasone. RELEVANCE AND NOVEL INFORMATION: To the best of our knowledge, this is the first reported case of urticaria pigmentosa in a domestic shorthair cat. This case also highlights the importance of biopsy after a thorough, systematic work-up in a cat with severe, intractable pruritus to reveal an uncommon disease pattern, as well as the efficacy of oral dexamethasone and cetirizine hydrochloride as a potential management option.

Prevalence of CD20+ cutaneous epitheliotropic T-cell lymphoma in dogs: a retrospective analysis of 24 cases (2011-2018) in the USA.

BACKGROUND: Limited information is known about the baseline frequency of canine CD20 positive (+ ) cutaneous epitheliotropic T-cell lymphoma. A single canine case report has been published. OBJECTIVES: To characterize the baseline frequency of CD20+ staining in cases of canine cutaneous epitheliotropic T-cell lymphoma; to assess its values as a prognostic indicator. ANIMALS: Skin biopsies from 24 client-owned animals diagnosed with cutaneous epitheliotropic lymphoma were assessed. METHODS AND MATERIALS: A retrospective review of medical records from 2011 to 2018. Clinical histories and previous histological and immunohistochemical slides were collected from 24 dogs and additional immunohistochemical staining was performed as needed to assess cases of cutaneous epitheliotropic T-cell lymphoma for CD3, CD20, CD79a and PAX5 staining characteristics. Staining characteristics were assessed for their statistical relationship to median survival time. RESULTS: Overall median survival time was 189 days following the onset of clinical signs and 99 days following definitive diagnosis; 54% of cases had CD20+ staining. There was no statistically significant correlation between staining characteristics and median survival time from onset of signs (P = 0.54) or from diagnosis (P = 0.61). CONCLUSIONS AND CLINICAL SIGNIFICANCE: Canine cutaneous epitheliotropic lymphoma has a higher instance of CD20 positivity than documented previously. This indicates that CD20 staining may be unsuitable to differentiate T-cell and B-cell cutaneous epitheliotropic lymphoma. This also may have therapeutic implications with the advent of canine CD20 monoclonal antibody therapies.

Comparing dermoscopy and histological examination of normal equine skin.

BACKGROUND: Dermoscopy is a noninvasive diagnostic technique that allows visualization of structures of the superficial dermis not visible with the naked eye. HYPOTHESIS/OBJECTIVES: To assess the usefulness and applicability of dermoscopy for evaluation of healthy equine skin. ANIMALS: Twelve healthy horses from a research herd. METHODS: Five regions (cheek, lateral neck, dorsum, flank and abdomen) were examined with contact dermoscopy using both nonpolarized and polarized light at both 17-fold and 24-fold magnification. These findings were compared to histological features of skin biopsies cut both longitudinally and transversely. RESULTS: Using a hand-held dermatoscope with nonpolarized light, epidermal ridges were observed. Using polarized light, follicular openings and distinctly separate epidermal openings of sweat gland ducts were observed in some but not all individuals. Similarities were noted between histological and dermoscopic results. CONCLUSIONS: Although not ideal for visualizing many structures in the superficial dermis of healthy equine skin, dermoscopy allowed visualization of epidermal ridges, hair shafts in the infundibular portion of the hair follicles and sweat gland duct openings. Dermoscopy could potentially be useful in the evaluation of diseases affecting the sweat glands, epidermis and hair shaft.

Coordinate expression of cytokeratins 7 and 14, vimentin, and Bcl-2 in canine cutaneous epithelial tumors and cysts.

Forty-seven canine cutaneous epithelial tumors and cysts were examined to determine coordinate expression of cytokeratins 7 (CK7) and 14 (CK14), vimentin, and Bcl-2 using commercially available antibodies. Within non-affected normal skin adjacent to tumors or cysts, CK7 expression was observed in luminal cells in apocrine glands; CK14 expression was observed in the stratum basale, stratum spinosum, stratum granulosum, basal layer of outer root sheath, sebaceous glands, and myoepithelial cells of apocrine glands; vimentin expression was observed in dermal papilla and scattered non-epithelial cells within the epidermis; and Bcl-2 expression was observed in scattered non-epithelial cells in the epidermis and some apocrine glands. The pattern of expression of CK7 and CK14 in cases of adenocarcinoma of the apocrine gland of the anal sac (CK7+/CK14-) and hepatoid gland tumors (CK7-/CK14+) may prove useful for diagnostic purposes. Loss of expression of CK14 and vimentin, identifying myoepithelial cells, was observed in apocrine and ceruminous adenocarcinomas. Differences in patterns of expression of Bcl-2 were observed between infundibular keratinizing acanthomas compared to trichoepitheliomas.