Possible Dissemination of a Panton-Valentine Leukocidin-Positive Livestock-Associated Methicillin-Resistant Staphylococcus aureus CC398 Clone in Tokyo, Japan.

In the last decade, methicillin-resistant Staphylococcus aureus (MRSA) has been identified in livestock animals, such as swine, poultry, and veal calves, and has been termed livestock-associated MRSA (LA-MRSA). LA-MRSA sequence type (ST) 398 strains can effectively infect and colonize humans, with subsequent human-to-human transmission in both community and hospital settings. Unlike other countries, LA-MRSA had not been reported in Japanese patients until 2019. However, we recently reported a case of intractable arthritis caused by an LA-MRSA CC398 (ST1232) clone, which is a single-locus variant of ST398, in a patient in Tokyo, Japan, with no animal contact (Nakaminami H, et al. Emerg Infect Dis. 2020; 26: 795-7.). Uniquely, the strain was positive for Panton-Valentine leukocidin. Here, we report the second such case in Japan. To prevent the dissemination of LA-MRSA in the Japanese community, the prevalence of the CC398 MRSA clone should be closely monitored in the future.