Nationwide surveillance of antibacterial susceptibility in bacterial respiratory pathogens in Japan, 2022-2023.

The emergence and spread of antimicrobial resistant (AMR) have become a major global concern. This nationwide surveillance study, conducted by the Japanese Society of Chemotherapy, Japanese Association for Infectious Diseases, and Japanese Society for Clinical Microbiology from 2022 to 2023, examined the antimicrobial susceptibility of respiratory pathogens. A total of 1057 bacterial isolates from 28 medical institutions, predominantly tertiary medical centers, were analyzed. Major pathogens included Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Findings revealed increasing resistance rates, with a notable rise in extended-spectrum β-lactamase (ESBL)-producing K. pneumoniae. Susceptibility to penicillin, cephalosporins, and carbapenems varied, with specific declines observed in several antibiotics relative to prior surveillance data. No metallo-β-lactamase (MBL)-producing P. aeruginosa strains were detected. These findings underscore the need for rigorous antimicrobial stewardship and continuous surveillance to curb the spread of resistant pathogens in Japan.