Mpox associated with Panton-Valentin leucocidin-producing methicillin-resistant Staphylococcus aureus among people with HIV.

We report three cases of mpox (disease caused by the monkeypox virus) that developed in people with HIV co-infected with Panton-Valentin leucocidin-producing methicillin-resistant Staphylococcus aureus (PVL-MRSA), diagnosed in mid-February 2023. All three cases had preserved HIV immune status, and their mpox was mild and resolved without antiviral medications, but the trigger for their visit was the presence and history of skin and soft tissue infections. Our cases suggest that mpox is already prevalent among sexually active MSM in Tokyo, Japan. PVL-MRSA has been extremely rare in the general population of Japan, but several literatures reported widespread prevalence of PVL-MRSA among sexually active MSM-HIV. Mpox will become prevalent in the future in a population of sexually active MSM at high risk for PVL-MRSA infection, requiring an understanding of the interaction and pathogenesis of the two diseases.