Background -Otitis externa is a common multifactorial disease in dogs. The diversity of the cutaneous microbiota in dogs appears to decrease in diseased states. However, little is known about the microbiota of the canine ear and how it is altered by disease.Hypothesis/Objectives -To describe the otic bacterial microbiota in dogs with otitis externa compared to healthy dogs.Animals -Samples were collected from 18 dogs with clinical and cytological evidence of otitis externa, and eight clinically normal dogs without cytological evidence of otitis externa.Methods and materials -DNA from each sample was isolated and Illumina â sequencing of the V4 hypervariable region of the 16S rRNA gene amplicons was performed. Sequences were processed using the bioinformatics software MOTHUR.Results -Bacteria from 27 different phyla were identified. Affected ears had significantly decreased alpha diversity when compared to healthy ears. Community structure and membership also differed between the two groups. Linear discriminant analysis effect size analysis identified 153 operational taxonomic units (OTUs) that were differentially abundant. Eleven OTUs were over-represented in the affected ears, including Staphylococcus, Pseudomonas and Parvimonas. Conclusions -The otic bacterial microbiota is much more complex than has been identified with previous culture-based studies; otitis externa is accompanied by broad and complex differences in the microbiota.

Reduced fungal richness and diversity was present in affected ears, with markedly higher relative abundances of Malassezia. The otic fungal mycobiota is much more complex than has been identified with culture-based studies.

OBJECTIVE-To compare early socialization practices between litters of breeders registered with the Canine Control Council (CCC) and litters of nonregistered breeders advertising puppies for sale in a local newspaper. DESIGN-Retrospective cohort study. Animals-80 litters of purebred and mixed-breed dogs from registered (n = 40) and non-registered (40) breeders. PROCEDURES-Registered breeders were randomly selected from the CCC website, and nonregistered breeders were randomly selected from a weekly advertising newspaper. The litter sold most recently by each breeder was then enrolled in the study. Information pertaining to socialization practices for each litter was obtained through a questionnaire administered over the telephone. RESULTS-Registered breeders generally had more breeding bitches and had more litters than did nonregistered breeders. Litters of registered breeders were more likely to have been socialized with adult dogs, people of different appearances, and various environmental stimuli, compared with litters of nonregistered breeders. Litters from registered breeders were also much less likely to have been the result of an unplanned pregnancy. CONCLUSIONS AND CLINICAL RELEVANCE-Among those breeders represented, litters of registered breeders received more socialization experience, compared with litters of nonregistered breeders. People purchasing puppies from nonregistered breeders should focus on socializing their puppies between the time of purchase and 14 weeks of age. Additional research is required to determine whether puppies from nonregistered breeders are at increased risk of behavioral problems and are therefore more likely to be relinquished to animal shelters or euthanized, relative to puppies from registered breeders.