Kawaguchiya Mitsuyo, Aung Meiji Soe, Urushibara Noriko, Ohashi Nobuhide, Kobayashi Nobuyuki, Kudo Kenji, Ito Masahiko, Kobayashi Nobumichi
Division of Hygiene, Department of Social Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan.
Medical Laboratory and Blood Center, Asahikawa Medical University Hospital, Asahikawa, Japan.
IJID Reg. 2025 Jun 27;16:100693. doi: 10.1016/j.ijregi.2025.100693. eCollection 2025 Sep.
This study aimed to elucidate the molecular characteristics and antimicrobial resistance of isolates from adults with invasive pneumococcal disease (IPD) in the northern main island of Japan.
A total of 45 isolates obtained from adults (aged 41-98 years) with IPD between 2017 and 2023 were analyzed for serotype, sequence type (ST), and antimicrobial susceptibility.
Of the 45 isolates, serotype 3-ST180 (24.4%) was the most prevalent, followed by 23A-ST338/ST5242 (13.3%); 23F-ST242/ST1437/ST3543 (8.9%); and 6D-ST282, 15A-ST63, 35B-ST558, and 34-ST1439/ST7388 (6.7% each), which collectively accounted for 73.4% of all isolates. The proportion of the pneumococcal conjugate vaccine (PCV) 13, PCV20, and 23-valent polysaccharide vaccine (PPSV23) serotypes were 44.5%, 46.7%, and 44.5%, respectively. The rate of non-susceptibility to penicillin was 24.4%, and the majority (n = 10 of 11, 90.9%) were also non-susceptible to erythromycin and tetracycline. The multidrug resistance rate for the non-PCV20/PPSV23 serotype was 83.3%, which was higher than the 71.4% for the vaccine serotypes. Among the non-PCV20/PPSV23 serotypes, 23A, 6D, 15A, 35B, and 6E (genetic variant of 6B) showed multidrug resistance with non-susceptibility to penicillin.
The present study revealed that the non-vaccine serotypes in IPD among adults were associated with a high prevalence of non-susceptibility to antimicrobial agents, suggesting the need for continuous surveillance.
本研究旨在阐明日本北部主岛侵袭性肺炎球菌病（IPD）成年患者分离株的分子特征及抗菌药物耐药性。
对2017年至2023年间从成年（41 - 98岁）IPD患者中获得的45株分离株进行血清型、序列型（ST）及抗菌药物敏感性分析。
45株分离株中，血清型3 - ST180最为常见（24.4%），其次是23A - ST338/ST5242（13.3%）；23F - ST242/ST1437/ST3543（8.9%）；以及6D - ST282、15A - ST63、35B - ST558和34 - ST1439/ST7388（各占6.7%），这些血清型共占所有分离株的73.4%。肺炎球菌结合疫苗（PCV）13、PCV20和23价多糖疫苗（PPSV23）血清型的比例分别为44.5%、46.7%和44.5%。对青霉素不敏感率为24.4%，大多数（11株中的10株，90.9%）对红霉素和四环素也不敏感。非PCV20/PPSV23血清型的多重耐药率为83.3%，高于疫苗血清型的71.4%。在非PCV20/PPSV23血清型中，23A、6D、15A、35B和6E（6B的基因变体）表现出对青霉素不敏感的多重耐药性。
本研究表明，成年IPD患者中的非疫苗血清型与抗菌药物不敏感的高流行率相关，提示需要持续监测。
