背景:医院获得性耐甲氧西林金黄色葡萄球菌(HA-MRSA)的特定流行病克隆是MRSA在全球范围内传播的原因。然而,近年来,社区获得性MRSA(CA-MRSA)克隆的分离率一直在增加。我们调查了京都和志贺地区HA-MRSA和CA-MRSA克隆的最新分子流行病学趋势,日本。
方法:使用基于PCR的开放阅读框分型(POT)方法,从2014年至2019年京都和志贺地区四家急性护理医院的住院患者临床标本中获得的所有非重复MRSA分离株进行分型。根据POT1值对CA-MRSA和HA-MRSA进行分类。我们对显示常见POT类型的代表性分离株进行了全基因组测序分析。
结果:本研究共纳入2413个分离株,包括1730个医院分离株和683个非医院分离株。HA-MRSA的比率从2014年的50.2%下降到2019年的19.0%,而CA-MRSA的比率从44.7%上升到76.4%(p<0.001)。属于最常见的10种POT类型的分离株(CA-MRSA,n=6;HA-MRSA,n=4)占所研究分离株的42%,是从3家或更多医院获得的。全基因组测序分析表明,POT类型为106-137-80、106-9-80、106-9-2和106-137-2的常见CA-MRSA分离株,POT类型为106-183-37和106-129-5的常见CA-MRSA分离株,POT类型为93-191-103、93-157-127、93-137-103和93-223-的HA-MRSA分离株属于STST1-SCCmecIV,和ST764-SCCmecII,分别。
结论:最近发生了从HA-MRSA到CA-MRSA的克隆转移,特定区域克隆在京都和滋贺地区的住院患者中普遍存在。
BACKGROUND: Specific epidemic clones of hospital-acquired methicillin-resistant Staphylococcus aureus (HA-MRSA) are responsible for the worldwide spread of MRSA. However, in recent years, the isolation of community-acquired MRSA (CA-MRSA) clones has been increasing. We investigated the latest molecular epidemiology trends of HA-MRSA and CA-MRSA clones in the Kyoto and Shiga regions, Japan.
METHODS: All nonduplicate MRSA isolates obtained from the clinical specimens of inpatients at four acute care hospitals in the Kyoto and Shiga regions between 2014 and 2019 were typed using the PCR-based open reading frame typing (POT) method. CA-MRSA and HA-MRSA were classified according to the POT1 values. We performed whole-genome sequencing analysis for representative isolates displaying common POT types.
RESULTS: A total of 2413 isolates were included in the study, comprising 1730 nosocomial and 683 nonnosocomial isolates. The rates of HA-MRSA decreased from 50.2% in 2014 to 19.0% in 2019, while those of CA-MRSA increased from 44.7% to 76.4% (p < 0.001). Isolates belonging to the most common 10 POT types (CA-MRSA, n = 6; HA-MRSA, n = 4) accounted for 42% of the isolates studied and were obtained from 3 or more hospitals. Whole-genome sequencing analysis showed that the common CA-MRSA isolates with POT types 106-137-80, 106-9-80, 106-9-2, and 106-137-2, those with POT types 106-183-37 and 106-129-5, and HA-MRSA isolates with POT types 93-191-103, 93-157-127, 93-137-103, and 93-223-111 belonged to ST8-SCCmecIV, ST1-SCCmecIV, and ST764-SCCmecII, respectively.
CONCLUSIONS: A recent clonal shift from HA-MRSA to CA-MRSA occurred, and specific regional clones were prevalent among inpatients in the Kyoto and Shiga regions.