中国中南地区耐甲氧西林敏感、耐药和异质性万古霉素中介金黄色葡萄球菌的分子特征和毒力因子。
Molecular characteristics and virulence factors in methicillin-susceptible, resistant, and heterogeneous vancomycin-intermediate Staphylococcus aureus from central-southern China.
机构信息
Department of Laboratory, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
Department of Laboratory, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
出版信息
J Microbiol Immunol Infect. 2015 Oct;48(5):490-6. doi: 10.1016/j.jmii.2014.03.003. Epub 2014 Apr 22.
BACKGROUND
Staphylococcus aureus is a leading cause of nosocomial infections. The purpose of this study was to evaluate the prevalence of methicillin-resistant S. aureus (MRSA) and heterogeneous vancomycin-intermediate S. aureus (hVISA), and compare the antimicrobial susceptibility, molecular characteristic, and virulence factors in methicillin-susceptible S. aureus (MSSA), MRSA, and hVISA from central-southern China.
METHODS
A total of 184 S. aureus were isolated from sterile body fluids. All isolates were subjected to population analysis profiling for the identification of hVISA phenotype and polymerase chain reaction analysis for genotyping and 31 virulence genes.
RESULTS
The prevalence of MRSA isolates was 41.8% in central-southern China. Of 77 MRSA isolates, 17 (22.1%) were identified as hVISA. The most common MRSA and MSSA clones were ST239-MRSA-SCCmecIII-t030-agr-I (55.8%) and ST188-MSSA-t189-agr-I (20.6%), respectively. The frequency of carriage of pvl, hemolysins, tst, and staphylococcal enterotoxin genes among MSSA isolates was significantly higher than that for MRSA isolates (p < 0.05); 98 MSSA isolates (53.3%) carried ≥ 10 tested virulence genes simultaneously, which was significantly higher than that of MRSA isolates (33.8%; p = 0.004). The 17 hVISA isolates carried a significantly small number of virulence genes; only two hVISA isolates carried ≥ 10 tested virulence genes simultaneously, and two hVISA isolates harbored only four virulence genes. Compared with other clonal complexes (CCs), CC1 and CC398 isolates harbored a higher frequency of exfoliatin genes, CC1 and CC59 harbored a higher frequency of pvl gene, and only CC1 isolates harbored lukED.
CONCLUSION
The prevalence of hVISA was considerably high in central-southern China. Simultaneous carriage of multiple virulence genes was common in S. aureus isolates; the virulence genes were more diverse and frequent among MSSA isolates than among MRSA isolates. Furthermore, the distribution of some virulence genes was correlated with the different S. aureus CCs.
背景
金黄色葡萄球菌是医院感染的主要致病菌。本研究旨在评估耐甲氧西林金黄色葡萄球菌（MRSA）和异质性万古霉素中介金黄色葡萄球菌（hVISA）在中国中南地区的流行情况，并比较中国中南地区甲氧西林敏感金黄色葡萄球菌（MSSA）、MRSA 和 hVISA 的抗菌药物敏感性、分子特征和毒力因子。
方法
从无菌体液中分离出 184 株金黄色葡萄球菌。所有分离株均进行群体分析谱分析以鉴定 hVISA 表型，并进行聚合酶链反应分析以进行基因分型和 31 种毒力基因分析。
结果
中国中南地区 MRSA 分离株的检出率为 41.8%。在 77 株 MRSA 分离株中，17 株（22.1%）鉴定为 hVISA。最常见的 MRSA 和 MSSA 克隆分别为 ST239-MRSA-SCCmecIII-t030-agr-I（55.8%）和 ST188-MSSA-t189-agr-I（20.6%）。MSSA 分离株携带 pvl、溶血性、tst 和葡萄球菌肠毒素基因的频率明显高于 MRSA 分离株（p<0.05）；98 株 MSSA 分离株（53.3%）同时携带≥10 种检测到的毒力基因，明显高于 MRSA 分离株（33.8%；p=0.004）。17 株 hVISA 分离株携带的毒力基因数量明显较少；只有 2 株 hVISA 分离株同时携带≥10 种检测到的毒力基因，且只有 2 株 hVISA 分离株仅携带 4 种毒力基因。与其他克隆群（CC）相比，CC1 和 CC398 分离株携带剥脱毒素基因的频率更高，CC1 和 CC59 携带 pvl 基因的频率更高，只有 CC1 分离株携带 lukED。
结论
中国中南地区 hVISA 的检出率相当高。金黄色葡萄球菌分离株常同时携带多种毒力基因；与 MRSA 分离株相比，MSSA 分离株的毒力基因更为多样和常见。此外，一些毒力基因的分布与不同的金黄色葡萄球菌 CC 有关。
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