Guo Yinjuan, Wang Bingjie, Rao Lulin, Wang Xinyi, Zhao Huilin, Li Meilan, Yu Fangyou
Department of Clinical Laboratory, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, 200433, People's Republic of China.
Respiratory Intensive Care Unit, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, 200433, People's Republic of China.
Infect Drug Resist. 2021 Nov 4;14:4591-4600. doi: 10.2147/IDR.S336200. eCollection 2021.
Methicillin-resistant (MRSA) infections have become a leading cause of severe infections in both healthcare and community settings. Mutations in the gene cause resistance to rifampin (RIF), a critical antibiotic for the treatment of multidrug-resistant . The aim of this study was to detect the molecular characteristics of RIF MRSA and analyze the gene mutations involved in RIF resistance.
A total of 49 RIF MRSA and 38 RIF MRSA isolates collected from seven cities in China were analyzed by multilocus sequence typing, staphylococcus chromosomal cassette (SCC) typing, typing, and gene mutations.
ST239-III-t030 (35/49, 71.4%), the major clone in RIF MRSA isolates; ST45-IV-t116 (16/38, 42.1%), the major clone in RIF MRSA isolates with mutations. RIF MRSA isolates were resistant to erythromycin, ciprofloxacin, tetracycline, gentamicin, and clindamycin. By contrast, RIF MRSA isolates with mutation were more susceptible to ciprofloxacin, tetracycline, and gentamicin. Forty-three (87.8%) isolates present the mutational change H481N and L466S, conferring 128-512 μg/mL RIF resistance. The four isolates with RIF MIC ≥ 1024 μg/mL had additional amino acid substitution: H481N, L466S, A473T (n=2); H481Y (n=2), associated with a high-level RIF resistance. Of 38 RIF MRSA isolates, two mutations were observed, including H481N (n=37) and A477D (n=1).
In conclusion, the predominant RIF MRSA clones in China were ST239-III-t030. Molecular characteristics, antibiotic-resistant profiles, and mutations between RIF MRSA and RIF MRSA were diverse. Antibiotics for treating patients with MRSA infections can be selected based on molecular characteristics.
耐甲氧西林金黄色葡萄球菌（MRSA）感染已成为医疗机构和社区环境中严重感染的主要原因。基因中的突变导致对利福平（RIF）耐药，利福平是治疗多重耐药菌的关键抗生素。本研究旨在检测耐利福平MRSA的分子特征，并分析与利福平耐药相关的基因突变。
对从中国七个城市收集的49株耐利福平MRSA和38株耐利福平MRSA分离株进行多位点序列分型、葡萄球菌染色体盒式（SCC）分型、分型及基因突变分析。
ST239-III-t030（35/49，71.4%）是耐利福平MRSA分离株中的主要克隆；ST45-IV-t116（16/38，42.1%）是有基因突变的耐利福平MRSA分离株中的主要克隆。耐利福平MRSA分离株对红霉素、环丙沙星、四环素、庆大霉素和克林霉素耐药。相比之下，有基因突变的耐利福平MRSA分离株对环丙沙星、四环素和庆大霉素更敏感。43株（87.8%）分离株出现H481N和L466S突变，导致对利福平耐药，耐药浓度为128 - 512μg/mL。利福平最低抑菌浓度（MIC）≥1024μg/mL的4株分离株有额外的氨基酸替换：H481N、L466S、A473T（n = 2）；H481Y（n = 2），与高水平利福平耐药相关。在38株耐利福平MRSA分离株中，观察到两种突变，包括H481N（n = 37）和A477D（n = 1）。
总之，中国耐利福平MRSA的主要克隆是ST239-III-t030。耐利福平MRSA和耐利福平MRSA之间的分子特征、抗生素耐药谱及基因突变各不相同。可根据分子特征选择治疗MRSA感染患者的抗生素。
