Rodent models are invaluable to understanding health and disease in many areas of biomedical research. Unfortunately, many models suffer from lack of phenotype reproducibility. Our laboratory has shown that differences in gut microbiota (GM) can modulate phenotypes of models of colon cancer and inflammatory bowel disease. We and others have also shown that a number of factors associated with rodent research, including vendor, cage system, and bedding can alter GM. The objective of this study was to expand these studies to examine the effect of additional bedding materials and methods of water decontamination on GM diversity and composition. To this end, Crl:CD1 (ICR) mice were housed on corn cob or compressed paper chip bedding and provided water that was decontaminated by four different methods: autoclaving with reverse osmosis, autoclaving with hydrochloric acid, autoclaving with sulfuric acid, and autoclaving alone. Feces was collected at day 0, and at day 28 (endpoint), fecal and cecal samples were collected. DNA was extracted from samples, amplified by PCR using conserved bacterial primer sets and subjected to next generation sequencing. Sequence data were analyzed using Qiime and groups were compared using principal coordinate analysis (PCoA) and permutational multivariate analysis of variance (PERMANOVA). Two factor PERMANOVA of cecal GM data revealed significant changes when comparing bedding and water decontamination methods, while no significant effects were noted in the fecal GM data. Subsequent PERMANOVA and PCoA of cecal data revealed that several combinations of bedding and water decontamination methods resulted in differing GM, highlighting the complexity by which environmental factors interact to modulate GM.

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.

The gut microbiota (GM) is the sum of hundreds of distinct microbial species that can equal or outnumber their host’ssomatic cells. The GM influences a multitude of physiologic and immunologic processes in the host, and changes in the GM have been shown to alter the phenotypes of animal models. Previous studies using rodents have also shown that the composition of the GM is affected by many factors, including diet, husbandry, housing, and the genetic background of the animals. However, limited information exists about factors that may modulate GM in other laboratory species, such as dogs. We sought to eliminate sporadic Giardia colonization of dogs using fenbendazole (FBZ), an antiprotozoal widely used in biomedical research dog colonies. Concerns that FBZ could have inadvertent effects on the canine GM led us to assess GM over the course of treatment. FBZ (50 mg/kg) was given orally to all dogs in 3 different facilities (n = 19 to 25) for 10 consecutive days. Fecal samples were obtained 2 d before the initiation of treatment, on the last day of treatment, and 2 wk after the completion of treatment. Targeted 16S rRNA gene sequencing was used to analyze fecal microbiota. All dogs were clinically normal throughout the sample collection period. Statistical analyses of data showed significant differences between dogs housed in the 3 different facilities, further emphasizing the effect of housing and husbandry factors on the GM. However,negligible differences were seen between time points, indicating that FBZ did not significantly alter the canine GM. Comparison of the GM of Giardia lamblia positive and negative dogs revealed no significant difference between the 2 groups. These findings suggest that FBZ can be used therapeutically in dogs with minimal impact on the GM. Furthermore, the presence ofG. lamblia in clinically normal animals may not be sufficient to influence the normal canine microbiota.

31Rodent models are invaluable to understanding health and disease in many areas of biomedical 32 research. Unfortunately, many models suffer from lack of phenotype reproducibility. Our 33 laboratory has shown that differences in gut microbiota (GM) can modulate phenotypes of 34 models of colon cancer and inflammatory bowel disease. We and others have also shown that 35 a number of factors associated with rodent research, including vendor, cage system, and 36 bedding can alter GM. The objective of this study was to expand these studies to examine the 37 effect of additional bedding materials and methods of water decontamination on GM diversity 38 and composition. To this end, Crl:CD1 (ICR) mice were housed on corn cob or compressed 39 paper chip bedding and provided water that was decontaminated by four commonly used 40 procedures: reverse osmosis, autoclaving, sulfuric acid treatment, or hydrochloric acid 41 treatment. Feces was collected at day 0, and at day 28 (endpoint), fecal and cecal samples 42 were collected. DNA was extracted from samples, amplified by PCR using conserved bacterial 43 primer sets and subjected to next generation sequencing. Sequence data were analyzed using 44Qiime and groups were compared using principal coordinate analysis (PCoA) and permutational 45 multivariate analysis of variance (PERMANOVA). Two factor PERMANOVA of cecal GM data 46 revealed significant changes when comparing bedding and water decontamination methods, 47 while no significant effects were noted in the fecal GM data. Subsequent PERMANOVA and 48PCoA of cecal data revealed that several combinations of bedding and water decontamination 49 methods resulted in differing GM, highlighting the complexity by which environmental factors

Background Micro‐organisms associated with canine otitis externa (OE) may cause biofilm‐associated infections (BAI). A key component of biofilm is microbial aggregate and extracellular polymeric substance (EPS). Periodic acid Schiff (PAS) can stain polysaccharide EPS in human otitis media with effusion, but this has not been tested in canine OE. There is no cytological definition for microbial aggregate, and definitive methods for identifying BAI in a clinical setting in canine OE have not been defined. Objectives To establish whether PAS stain can identify polysaccharide matrix on cytological smears; and to determine the reproducibility of identification of microbial aggregates within a discrete area of stained matrix, using paired modified Wright’s and PAS‐stained smears. Animals Forty privately‐owned dogs presenting to a dermatological referral practice. Methods and materials In this prospective, cross‐sectional study, three investigators independently and blindly classified 40 paired modified Wright’s–PAS slide sets into groups: aggregate‐associated infection (AAI) and non‐AAI (n = 27); and control (n = 13). Agreement between investigators for presence of AAI was measured using Fleiss’ kappa statistic (FK). Agreement between investigators and dermatologists for presence of AAI upon cytological evaluation, and suspected BAI based on clinical examination, was measured using Cohen’s kappa statistic. Results The matrix was confirmed to stain PAS‐positive. Interinvestigator agreement for AAI was very good using PAS (0.82 FK) and fair using modified‐Wright’s (MW) (0.33 FK). Reproducible cytological features associated with AAI were the presence of: three or more distinct aggregates (0.76 FK); discrete areas of PAS‐positive matrix (0.70 FK); and the presence of high‐density material (0.70 FK) using PAS stain. Conclusion PAS can stain the extracellular matrix on otic smears, and a novel protocol for reproducible identification of cytological features such as microbial aggregates has been established.