Relationship between clinical manifestations and pulsed-field gel profiles of Streptococcus canis isolates from dogs and cats

Little is known regarding the degree of genotypic relatedness between Streptococcus canis isolates from dogs and cats. The purpose of this study was to determine whether correlations existed between the genotypes of canine and feline S. canis isolates as determined using pulsed-field gel electrophoresis (PFGE) and different clinical manifestations of disease. Eighty-two isolates of S. canis were examined that had been collected from dogs and cats presenting to the University of California, Davis Veterinary Medical Teaching Hospital (VMTH) between 1998 and 2005. Associated clinical manifestations included sepsis, otitis, pyometra, skin infections, necrotizing fasciitis, respiratory disease, and urinary tract infections. In addition, 9 feline isolates from a southern California shelter that experienced an outbreak of S. canis infection manifesting as necrotizing fasciitis and death were examined. Bacterial isolates were characterized by PFGE analysis using the restriction enzyme SmaI. The relationships between banding patterns were analyzed using gel analysis software combined with visual interpretation. The feline shelter isolates of S. canis were 99% similar in bacterial PFGE profile. The remainder of samples had less than 80% similarity in PFGE banding patterns. The relatedness of the PFGE profile in the feline shelter isolates suggested a clonal origin. In the isolates from the VMTH population, there was no relationship between specific disease manifestations and PFGE profile. PFGE typing does not appear to be useful for identifying isolates associated with specific disease presentations; however may be more useful to identify outbreaks of S. canis infections or to detect clonal populations in outbreaks.