Scrotal ulcer due to community-acquired methicillin-resistant Staphylococcus aureus USA300 clone in an HIV-positive man who has sex with men in Japan: a case report

[Genitoanal infections caused by Panton-Valentine leukocidin (PVL)-positive Staphylococcus aureus : Smear infection or sexually transmitted disease?]

Panton-Valentine leukocidin (PVL) is a pore-forming exotoxin produced by certain Staphylococcus (S.) aureus strains, which is responsible for the increased virulence of the pathogen. Thus, infections caused by PVL-positive S. aureus tend to recur. Usually, the infection is a smear infection, which can cause folliculitis and purulent lid margin inflammation in addition to the classic mucocutaneous abscesses. Recently, recurrent genitoanal infections caused by PVL-positive S. aureus have also been described. In most cases, this is a sexually transmitted disease. Currently, it is assumed that most infections are imported from abroad. In addition to treatment of these infections, decolonization should be performed for prophylaxis of recurrence.

Emergence of community-associated methicillin-resistant Staphylococcus aureus ΨUSA300 among Japanese people with HIV, resulted from stepwise mutations in 2010s

Although infection with the methicillin-resistant Staphylococcus aureus (MRSA) clone USA300 is extremely rare in Japan, the uniquely evolved clone ΨUSA300 has been reported in Japan. An outbreak of a distinct USA300 clone was recently reported in an HIV/AIDS referral hospital in Tokyo. The present study investigated the evolutionary origin and genetic diversity of USA300-related clones causing regional outbreaks among people living with HIV (PLWHIV) in Tokyo. MRSA isolates collected from PLWHIV in an HIV/AIDS referral center in Tokyo were subjected to whole-genome sequencing and their genetic features were compared with those of previously described USA300 MRSA genomes. Of the 28 MRSAs isolated in 2016-2019, 23 (82.1%) were identified as USA300, with 22 (95.6%) of the latter identified as ΨUSA300. Although the genomic structure of ΨUSA300 was identical to the structures of reference USA300 strains, one clade (cluster A) was found to have acquired 29 previously identified lineage-specific mutations in a stepwise manner. The estimated divergence dates of ΨUSA300 and Cluster A were 2009 and 2012, respectively. These findings suggested that the ΨUSA300 clone had spread among PLWHIVs in Tokyo in the early 2010s, with stepwise acquisition of lineage-specific nonsynonymous mutations.

An Outbreak of USA300 Methicillin-Resistant Staphylococcus aureus Among People With HIV in Japan

BACKGROUND

USA300 produces Panton-Valentin leucocidin (PVL) and is known as a predominant community-associated methicillin-resistant Staphylococcus aureus (MRSA) strain in the United States, but it was extremely rare in Japan. We report here an outbreak of USA300 in people with HIV (PWH) in Tokyo, Japan.

METHODS

We analyzed the cases of PVL-MRSA infection between 2010 and 2020 and screened for nasal colonization of PVL-MRSA in PWH who visited an HIV/AIDS referral hospital from December 2019 to March 2020. Whole-genome sequencing-based single nucleotide polymorphism (SNP) analysis was performed on these isolates.

RESULTS

During the study period, a total of 21 PVL-MRSA infections in 14 patients were identified after 2014. The carriage prevalence was 4.3% (12/277) and PVL-MRSA carriers were more likely to have sexually transmitted infections (STIs) within a year compared with patients who had neither a history of PVL-MRSA infection nor colonization (33.3% [4/12] vs 10.1% [26/258]; P = .03). SNP analysis showed that all 26 isolates were ST8-SCCmecIVa-USA300. Twenty-four isolates were closely related (≤100 SNP differences) and had the nonsynonymous SNPs associated with carbohydrate metabolism and antimicrobial tolerance.

CONCLUSIONS

An outbreak of USA300 has been occurring among PWH in Tokyo and a history of STI was a risk of colonization.