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好文推荐:内蒙古地区样本MRSA 和MSSA 临床分离株agr 分型特征研究
作者:薛东力,王俊瑞,额尔德木图,等 来源:转化医学电子杂志 2017-05-08

  

 【摘 要】目的:探究金黄色葡萄球菌附属基因调节子(agr)在耐甲氧西林金黄色葡萄球菌(MRSA)和甲氧西林敏感金黄色葡萄球菌(MSSA) 临床株中的分布特征. 方法: 以50 株MSSA 株和40 株MRSA 株作为研究对象,采用多位点序列分型方法(MLST)检测这些菌株的ST 型,进一步采用PCR 方法检测agr Ⅰ~Ⅳ型基因在2 组金黄色葡萄球菌以及不同ST 型金黄色葡萄球菌中的分布. 结果:MLST 结果显示, MRSA 株主要为ST⁃239 型(36 株,90.0%),MSSA 主要为ST⁃5 型(10株,20.0%),其次为ST⁃7 型(9 株,18.0%). 90 株金黄色葡萄球菌中agr⁃Ⅰ基因占86.7%(78 株),agr⁃Ⅱ基因占24.4%(22株),agr⁃Ⅲ基因占3.3%(3 株),agr⁃Ⅳ基因占3.3%(3 株).MRSA 株主要携带agr⁃Ⅰ基因(97.5%/78.0%,P <0.05),而agr⁃Ⅱ基因携带率明显低于MSSA ,差异具有统计学意义(P<0.05). Agr 基因调控的毒力基因中,hla 和fnbA 基因表达率均为100%(90株,90/90),sea 基因表达率为47.8%(43 株,43/90).结论:MRSA 株和MSSA 株agr 基因分型特征差异显著,agr⁃I型基因在MRSA 株中呈优势表达,其对MRSA 株毒力调控基因表达的影响机制值得进一步研究.

  【关键词】金黄色葡萄球菌;agr 分型;多位点序列分型

Study on the Agr genotyping features of MRSA and MSSA clinical isolates from Inner Mongolia

  XUE Dong⁃Li1, WANG Jun⁃Rui2, Erdemtuu3, SUN Peng4, LANHai⁃Xia5

【Abstract】AIM: To investigate the distribution characteristics of accessory gene regulator (agr) in clinical strains of methicillin⁃ resistant staphylococcus aureus (MRSA) and methicillin sensitive staphylococcus aureus ( MSSA). METHODS: A total of 50 strains of MRSA and 40 strains of MSSA were selected as the research objects. The multilocus sequence typing (MLST) was used to detect the ST types, then polymerase chain reaction (PCR) was used to detect the distribution of agrⅠ~ Ⅳgenes in these 2 groups of staphylococcus strains and staphylococcus aureus with different ST types. RESULTS: The MLST showed that MRSA strains were mainly clustered into ST⁃239 type (36 strains,90%), and MSSA strains mainly belonged to ST⁃5 (10 strains,20%), followed by ST⁃7 (9 strains, 18%). Among the 90 strains of staphylococcus aureus tested, the positive rate agr⁃Ⅰ genes was 86.7% (78 strains), and positive rates of the other three agr genes were respectively 24.4% (22 strains), 3.3% (3 strains)and 3.3% (3 strains). MRSA strains carried higher rate of agr⁃Ⅰgene (97.5% / 78%, P<0.05), while the carrying rate of agr⁃Ⅱ gene in the MRSA strains was significantly lower than that of the MSSA (P<0.05). As one of the virulence genes regulated by agr regulatary system, expression rate of  both hla and fnbA were 100% (90 strains, 90/90), while the carrying rate of sea gene was 47.8% (43 strains, 43/90). CONCLUSION: Agr genotyping features of MRSA and MSSA strains tested in this study are significantly different. Agr⁃Ⅰ gene is predominatly expressed  in MRSA strains, and the regulatory mechanism of this regulating system in MRSA strains is still needed to be further investigated.

  【Keywords】staphylococcus aureus; Agr genotyping; multilocus sequence typing

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