Clinical significance of identification of Sphingomonas paucimobilis on bacterial culture in companion dogs and cats.

Background: Sphingomonas paucimobilis is part of the commensal microbiota of many animals but considered an emerging opportunistic pathogen in humans. Its occurrence and clinical relevance in dogs and cats is unknown. Objectives: We aimed to investigate the clinical significance of identification of S. paucimobilis on bacterial culture samples from dogs and cats. Methods: Retrospective longitudinal study. Medical records of dogs and cats with documented growth of S. paucimobilis from a single veterinary hospital were reviewed. Characteristics of the isolate (site, quantitative assessment, co-infections, sensitivity testing) and potential inciting causes (concurrent antibiotic treatment, immunosuppression, comorbidities) were retrieved. When possible, follow-up data were collected to document response to treatment and outcomes. Results: Ninety microbiology reports from 80 dogs and 10 cats were included. The most common site of isolation was the respiratory tract (33/90) followed by urine and skin (13/90 each). Pure growths were less common (9/90) than mixed. Sensitivity testing was only available from three cases. Most animals were treated with antimicrobials (70/90). Response to treatment was available for 78 animals and outcomes for 87. Most animals experienced a resolution of clinical signs (66/78), of which 12/66 had negative repeat culture. Thirty-four animals died during the follow-up period; five of those (all isolated from the respiratory tract of dogs, one of which a pure growth) were possibly related to S. paucimobilis infection. Conclusion: S. paucimobilis isolated from dogs and cats is often incidental, however it may be clinically significant when isolated from the respiratory tract in dogs.