Center for Hospital Infection Control, Chinese PLA Institute for Disease Control & Prevention, Academy of Military Medical Sciences, Beijing, China College of Food Science and Engineering, Shandong Agricultural University Shandong Agricultural University, Tai'an, China.
Center for Hospital Infection Control, Chinese PLA Institute for Disease Control & Prevention, Academy of Military Medical Sciences, Beijing, China.
J Antimicrob Chemother. 2015 Mar;70(3):653-7. doi: 10.1093/jac/dku456. Epub 2014 Nov 27.
This study was designed to demonstrate the characteristics of qacA/B-positive Staphylococcus aureus in China.
One hundred and forty-five MRSA and 178 MSSA from clinical specimens from seven hospitals in different regions of China, 70 MRSA from superficial sites of patients and 106 MRSA from environmental samples from an ICU were collected and screened for the presence of the qacA/B gene. The qacA/B-positive isolates and 72 randomly selected qacA/B-negative control isolates were further characterized by MLST, spa typing and detection of toxin genes, as well as antimicrobial and chlorhexidine susceptibility. SCCmec typing was conducted for MRSA. PFGE was conducted for qacA/B-positive isolates.
Twenty-five (7.8%) of the 321 MRSA isolates harboured qacA/B, including 11 isolates from clinical specimens (7.6%), 12 isolates from patients' superficial sites (17.1%) and 2 isolates from an ICU environment (1.9%). Ten and five qacA/B-positive MRSA were identified as ST239-t030-MRSA-III and ST239-t037-MRSA-III, respectively. Six PFGE clusters and five singletons were identified among the 25 qacA/B-positive MRSA. Only one (0.6%) of the 178 MSSA isolates harboured qacA/B. qacA/B carriage in MRSA was statistically associated with spa-t037 and the presence of mupA. Compared with qacA/B-negative MRSA, the qacA/B-positive MRSA exhibited a lower susceptibility to chlorhexidine and higher resistance rates to clindamycin and trimethoprim/sulfamethoxazole.
Carriage of qacA/B, although it had a low prevalence, might be the main reason for declining susceptibility to chlorhexidine in MRSA from Chinese patients and is probably associated with spa-t037 and the presence of the mupA gene.
本研究旨在展示中国 qacA/B 阳性金黄色葡萄球菌的特征。
从中国不同地区 7 家医院的临床标本中收集了 145 株耐甲氧西林金黄色葡萄球菌（MRSA）和 178 株甲氧西林敏感金黄色葡萄球菌（MSSA）、70 株来自患者体表部位的 MRSA 和 106 株来自 ICU 环境的 MRSA，筛选 qacA/B 基因的存在。对 qacA/B 阳性分离株和 72 株随机选择的 qacA/B 阴性对照分离株进行 MLST、spa 分型和毒素基因检测，以及抗菌和氯己定药敏试验。对 MRSA 进行 SCCmec 分型，对 qacA/B 阳性分离株进行 PFGE。
321 株 MRSA 中有 25 株（7.8%）携带 qacA/B，包括 11 株临床标本分离株（7.6%）、12 株患者体表部位分离株（17.1%）和 2 株 ICU 环境分离株（1.9%）。10 株和 5 株 qacA/B 阳性 MRSA 分别鉴定为 ST239-t030-MRSA-III 和 ST239-t037-MRSA-III。25 株 qacA/B 阳性 MRSA 中鉴定出 6 个 PFGE 簇和 5 个单克隆。178 株 MSSA 中仅 1 株（0.6%）携带 qacA/B。MRSA 中 qacA/B 的携带与 spa-t037 和 mupA 的存在呈统计学相关。与 qacA/B 阴性 MRSA 相比，qacA/B 阳性 MRSA 对氯己定的敏感性较低，对克林霉素和复方磺胺甲噁唑的耐药率较高。
尽管 qacA/B 的携带率较低，但可能是导致中国患者 MRSA 对氯己定敏感性下降的主要原因，可能与 spa-t037 和 mupA 基因有关。
