Bacterial species distribution and antimicrobial susceptibility of canine ocular isolates in Japan: retrospective analysis of a diagnostic laboratory database.

Abstract

This retrospective study investigated the bacterial species distribution and antimicrobial susceptibility of canine ocular isolates submitted to a Japanese diagnostic laboratory between October 2022 and March 2026. A total of 737 isolates were recovered, with Staphylococcus pseudintermedius (248/737, 33.6%) and Streptococcus canis (116/737, 15.7%) the most common isolates. Notably, 100 (40.3%) of the S. pseudintermedius isolates were methicillin-resistant. Cefotaxime demonstrated high activity against major Gram-positive pathogens, except for methicillin-resistant S. pseudintermedius, and Escherichia coli. In contrast, susceptibility to gatifloxacin varied markedly among the species, whereas the spectrum of gentamicin and polymyxin B was limited due to intrinsic resistance among common Gram-positive pathogens. These findings provide useful information for empirical antimicrobial selection in canine ocular infections in Japan.