重症监护病房患者金黄色葡萄球菌感染的分子流行病学研究

Molecular epidemiology study of ICU patients with Staphylococcus aureus infection

目的通过对重症监护病房患者金黄色葡萄球菌（SA）感染的分子流行病学研究,为临床预防和研究SA感染提供科学依据。方法收集重症监护病房近3年SA培养阳性病例52例,（去除同一患者相同和不同部位标本）采用多重PCR扩增SA的毒素基因tst和sec,分析毒素基因的存在与发热的关系,通过PCR扩增耐甲氧西林金黄色葡萄球菌（MRSA）基因组稀有限制区旁的DNA序列,对MRSA进行基因分型。结果 52例患者中,19例为对甲氧西林敏感的金黄色葡萄球菌（MSSA）,33例为MRSA,其中有22例MRSA携带tst和sec基因（66.7%）,显著高于MSSA 7例携带tst和sec基因（P〈0.05）;37例伴有发热,其中29例含有tst和sec基因,15例不伴发热,其中5例含tst和sec基因,发热组携带两种基因比率显著高于不发热组（P〈0.05）;稀有限制区PCR（IRS-PCR）分型表明,2012∽2014年感染MRSA的33例患者有22例为同种基因型。结论 tst和sec基因的存在可能与SA引起的发热有关,近3年该病房存在MRSA暴发流行可能。

Objective To perform the molecular epidemiology study of ICU patients infected with Staphylococcus aureus（SA） to provide a scientific basis for clinical infection prevention and research of SA. Methods 52 cases of SA positive culture （excluding the specimens from same and different parts in the same patient） were collected from ICU in the recent three years. The toxin gene tst and sec of SA were amplified by using multiple PCR, and the relationships between fever and toxin genes was analyzed. The DNA sequence of methieillin resistant Staphylococcus aureus （MRSA） genome near infrequent restriction site was amplified by PCR, and the genotyping of MRSA was performed. Results In 52 patients, 19 cases were infected by methicillin sensitive Staphylo- coccus aureus（MSSA） and 33 cases were infected by MRSA. There were 22 cases of MRSA carrying tst and see genes（66.7%）, which was significantly higher than 7 cases of MSSA carrying tst and sec genes（P〈0.05）. 29 of 37 cases with fever contained tst and sec genes,and 5 of 15 cases without fever contained tst and sec genes. The proportion of carrying two genes in the fever group was significantly higher than that in non-fever group（P〈0.05）. The infrequent restriction site PCR（IRS-PCR） genotyping showed that 22 of 33 patients infected with MRSA had the same genotype during 2012--2014. Conclusion Fever caused by SA may be related with sec and tst genes. MRSA may outbreaks in this ward in the next three years.