Antiseptic susceptibility profiles of canine pyoderma-associated staphylococci in Japan: first identification of plasmid-borne in .

INTRODUCTION

International guidelines recommend the use of antiseptics, such as chlorhexidine, to treat canine pyoderma. However, data on the antiseptic susceptibility of its primary causative agents, and , in Japan are limited.

METHODS

We performed antiseptic susceptibility testing and polymerase chain reaction (PCR) screening for antiseptic resistance-associated genes in these species. In addition, hybrid genome sequencing was conducted for a resistant isolate to investigate the genetic context of resistance genes.

RESULTS

Most isolates exhibited low minimum inhibitory concentrations for the tested antiseptics, although some inter-strain variations were observed. One isolate (SC18) was identified as smr-positive, representing only the second global report and the first from Japan. Phylogenetic analysis using publicly available genome data revealed that SC18 belongs to the major lineage of . Hybrid genome sequencing further demonstrated, for the first time, that in is plasmid-borne. Notably, this plasmid was also identified in a human-derived strain (KSE124-2) in Japan, suggesting plasmid-mediated interspecies transmission between humans and companion animals.

DISCUSSION

These findings highlight the need for continued surveillance of antiseptic resistance-associated genes, which may contribute to reduced phenotypic susceptibility and pose a potential public health concern.