Department of Microbiology, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan.
Pharmaceutical Department, Yokohama Rosai Hospital, Kanagawa, Japan.
J Med Microbiol. 2020 Feb;69(2):239-243. doi: 10.1099/jmm.0.001154. Epub 2020 Jan 21.
Recently, a clone with low susceptibility to quinolones emerged in paediatric patients in Japan. Isolates of this clone survived for a long time when exposed to the therapeutic concentration of quinolones, despite being classified as 'susceptible' under the criteria of the Clinical and Laboratory Standards Institute. In the present study, we report the first outbreak of this clone in paediatric patients in 2018. Our aim was to characterise the first outbreak of an clone with low susceptibility to quinolones. All isolates (=62), collected at a Japanese teaching hospital in 2018, were characterized by both antimicrobial susceptibility tests and multilocus sequence typing. In addition, the similarity in genetic backgrounds was analysed by PFGE. Among all the isolates (=62), quinolone low-susceptible isolates accounted for 19.4 % (=12). Seven out of 12 isolates were identified as sequence type 422 (ST422) and showed more than 90 % similarity to each other by PFGE analysis. All ST422 isolates exhibited identical amino acid substitutions in both quinolone resistance-determining regions in GyrA and ParC. In addition, all these isolates were from paediatric patients who had been referred by different primary care clinics and had no relationship to each other. In this study, we describe an outbreak of a quinolone low-susceptible ST422 clone in paediatric patients in Japan. Because ST422 isolates have already been reported in at least five other countries, it has the potential to spread worldwide.
最近，在日本的儿科患者中出现了一种对喹诺酮类药物低敏感性的克隆。尽管根据临床和实验室标准研究所的标准，这些克隆被归类为“敏感”，但在接触治疗浓度的喹诺酮类药物时，它们仍能存活很长时间。在本研究中，我们报告了 2018 年这种克隆在儿科患者中的首次爆发。我们的目的是描述对喹诺酮类药物低敏感性克隆的首次爆发。在 2018 年，从日本一家教学医院采集了所有 62 株分离株，通过抗菌药物敏感性试验和多位点序列分型进行了特征描述。此外，还通过 PFGE 分析了遗传背景的相似性。在所有分离株（=62）中，对喹诺酮类药物低敏感性的分离株占 19.4%（=12）。在这 12 株分离株中，有 7 株被鉴定为 422 型序列（ST422），通过 PFGE 分析，它们彼此之间的相似度超过 90%。所有 ST422 分离株在 GyrA 和 ParC 的喹诺酮耐药决定区均表现出相同的氨基酸取代。此外，所有这些分离株均来自儿科患者，这些患者是由不同的初级保健诊所转来的，彼此之间没有关系。在这项研究中，我们描述了日本儿科患者中喹诺酮类药物低敏感性 ST422 克隆的爆发。由于 ST422 分离株已经在至少五个其他国家报告过，因此它有可能在全球范围内传播。
