Department of Pediatrics and Adolescent Medicine, Juntendo University Graduate School of Medicine, Tokyo, Japan.
Department of Infection Control Science, Juntendo University Graduate School of Medicine, Tokyo, Japan.
Pediatr Int. 2020 Aug;62(8):911-919. doi: 10.1111/ped.14241. Epub 2020 Aug 3.
There have been few reports on the genetic structure of the current population of methicillin-resistant Staphylococcus aureus (MRSA) from neonatal intensive care units (NICUs) in Japan. In the present study we conducted a molecular epidemiological analysis based on whole genome sequencing against MRSA strains in a Japanese NICU.
We performed genotyping by whole genome sequencing, polymerase chain reaction-based typing of Staphylococcal cassette chromosome mec (SCCmec) and polymerase chain reaction-based open-reading frame typing against 57 MRSA strains from fecal or nasal specimens from NICU patients in Juntendo University Shizuoka Hospital in 2013-2014.
Forty-nine MRSA strains (86.0%) exhibited a clonal complex (CC) 1, and were divided into three sequence types (STs): ST2725 (n = 25), ST2764 (n = 21), and ST1 (n = 3). All CC1 MRSA strains had SCCmec IVa, and were resistant to new quinolones, which are limited in pediatric use, suggesting that these strains were derived from adult MRSA clones. Single nucleotide polymorphism differences of both ≤10 and >100 nucleotides were observed by pairwise, single nucleotide polymorphism analysis among ST2725 and ST2764 MRSA strains, respectively. Seven ST8 MRSA strains (12.2%) were isolated, and no strain exhibiting the Japanese hospital-associated MRSA genotype (ST5/SCCmec II) was isolated in this study.
Our molecular epidemiological analysis suggested that ST2725 and ST2764 MRSA strains had genetic diversity that could not be explained only by a recent transmission event in the NICU. These MRSA clones might be disseminated in other Japanese hospital facilities as new endemic clones. Our results are expected to contribute to the improvement of infection control measures of MRSA in NICUs.
目前关于日本新生儿重症监护病房（NICU）耐甲氧西林金黄色葡萄球菌（MRSA）的种群遗传结构的报告很少。在本研究中，我们对 2013-2014 年从日本顺天堂大学静冈医院 NICU 患者粪便或鼻腔标本中分离的 57 株 MRSA 菌株进行了全基因组测序，基于全基因组测序、基于聚合酶链反应的葡萄球菌盒染色体 mec（SCCmec）分型和基于聚合酶链反应的开放阅读框分型进行了分子流行病学分析。
我们对 2013-2014 年从日本顺天堂大学静冈医院 NICU 患者粪便或鼻腔标本中分离的 57 株 MRSA 菌株进行了全基因组测序，基于聚合酶链反应的葡萄球菌盒染色体 mec（SCCmec）分型和基于聚合酶链反应的开放阅读框分型进行了基因分型。
49 株 MRSA 菌株（86.0%）表现出克隆复合体（CC）1，分为三个序列型（ST）：ST2725（n=25）、ST2764（n=21）和 ST1（n=3）。所有 CC1 MRSA 菌株均携带 SCCmec IVa，对新喹诺酮类药物耐药，这些药物在儿科使用受限，提示这些菌株来源于成人 MRSA 克隆。ST2725 和 ST2764 MRSA 菌株之间的单核苷酸多态性分析显示，两者之间的单核苷酸多态性差异≤10 和>100 个核苷酸分别为 7 株和 27 株。本研究未分离到日本医院相关 MRSA 基因型（ST5/SCCmec II）的 7 株 ST8 MRSA 菌株。
我们的分子流行病学分析表明，ST2725 和 ST2764 MRSA 菌株的遗传多样性不能仅用 NICU 近期传播事件来解释。这些 MRSA 克隆可能作为新的地方性克隆在其他日本医院设施中传播。我们的研究结果有望为改善 NICU 中 MRSA 的感染控制措施做出贡献。
