Zhao Rui, Du Bingyu, Hu Lingling, Li Chenxi, Xue Fen, Wang Xing, Jiang Changhong, Wang Jinghua, Zhao Yanfeng
Clinical Microbiology Laboratory, Shanghai Center for Clinical Laboratory, Shanghai, China.
Laboratory Medicine Center, Second Affiliated Hospital, Nanjing Medical University, Nanjing, China.
Front Cell Infect Microbiol. 2025 Jan 30;15:1491658. doi: 10.3389/fcimb.2025.1491658. eCollection 2025.
Methicillin-resistant (MRSA) exhibits diverse genotypes with varying virulence and resistance profiles, particularly in the context of bloodstream infections (BSI). This study investigates the prevalence of the , , and genes among MRSA isolates from bloodstream infections in southern China and analyzes their genetic relatedness.
A polymerase chain reaction (PCR) assay was developed to detect the presence of the gene, which is associated with nasal colonization, immune evasion, and virulence, the mupirocin resistance gene , and the chlorhexidine tolerance gene in a total of 77 MRSA isolates. Multilocus sequence typing (MLST) was performed to determine the sequence types (STs) and assess the genetic relatedness of the isolates. The resistance of these strains to 16 antibiotics was also analyzed. The distribution of these genes and their association with epidemic STs were analyzed.
A total of 26 STs were identified, with notable prevalence in five epidemic clones: ST59, ST5, and ST764. The prevalence of the , , and qacA/B genes across all isolates was 23.4%, 33.8%, and 79.2%, respectively. Specifically, the frequency of the gene was highest in ST59 (29.4%), ST239 (100%), and ST764 (37.5%); was most prevalent in ST5 (66.7%), ST59 (17.6%), ST764 (37.5%), and ST15 (100%); was predominantly found in ST59 (88.2%), ST5 (66.7%), ST398 (85.7%), ST764 (50.0%), and ST239 (100%). The gene distribution patterns revealed that strains were closely associated with epidemic clones ST6290 and ST88, whereas strains were linked to ST59, ST239, and ST764.
Notably, forty-seven (61%) MRSA BSI strains were multidrug-resistant, with the majority exhibiting resistance to penicillin, erythromycin, and clindamycin. Major MRSA clones in southern China include ST59, ST5, ST764, and ST398. In this study, , and genes were present in the MRSA isolates, with the gene being the most prevalent. Variations in the prevalence of virulence and resistance genes among these epidemic strains underscore the need for targeted infection control measures. These findings contribute to a better understanding of the genetic epidemiology of MRSA in the region, facilitating the development of effective prevention and control strategies for BSI.
耐甲氧西林金黄色葡萄球菌（MRSA）表现出多种基因型，其毒力和耐药性各不相同，在血流感染（BSI）的情况下尤其如此。本研究调查了中国南方血流感染的MRSA分离株中 、 和 基因的流行情况，并分析了它们的遗传相关性。
开发了一种聚合酶链反应（PCR）检测方法，以检测总共77株MRSA分离株中与鼻腔定植、免疫逃避和毒力相关的 基因、莫匹罗星耐药基因 和洗必泰耐受基因 的存在情况。进行多位点序列分型（MLST）以确定序列类型（STs）并评估分离株的遗传相关性。还分析了这些菌株对16种抗生素的耐药性。分析了这些基因的分布及其与流行STs的关联。
共鉴定出26种STs，其中五个流行克隆中占比显著：ST59、ST5和ST764。所有分离株中 、 和qacA/B基因的流行率分别为23.4%、33.8%和79.2%。具体而言， 基因在ST59（29.4%）、ST239（100%）和ST764（37.5%）中频率最高； 在ST5（66.7%）、ST59（17.6%）、ST764（37.5%）和ST15（100%）中最为普遍； 主要存在于ST59（88.2%）、ST5（66.7%）、ST398（85.7%）、ST764（50.0%）和ST239（100%）中。基因分布模式显示 菌株与流行克隆ST6290和ST88密切相关，而 菌株与ST59、ST239和ST764相关。
值得注意的是，47株（61%）MRSA BSI菌株具有多重耐药性，大多数对青霉素、红霉素和克林霉素耐药。中国南方主要的MRSA克隆包括ST59、ST5、ST764和ST398。在本研究中，MRSA分离株中存在 、 和 基因，其中 基因最为普遍。这些流行菌株中毒力和耐药基因流行率的差异凸显了针对性感染控制措施的必要性。这些发现有助于更好地了解该地区MRSA的遗传流行病学，促进BSI有效防控策略的制定。
