金黄色葡萄球菌临床分离株肠毒素基因的调查分析

摘要：目的检测临床分离的金黄色葡萄球菌（SA）肠毒素基因，了解肠毒素基因的携带情况与SA耐药的关系。方法采用聚合
酶链反应检测SA mecA基因和肠毒素基因，了解肠毒素基因在SA中分布的状况，并对其进行耐药性分析。结果67株甲氧西
林耐药的SA（MRSA）和57株甲氧西林敏感的SA（MSSA）肠毒素基因携带率（100% vs 83.5%）无明显差异（χ2=0.203，P>0.05）。
肠毒素基因检出率为93.5%（116株），其中SEA、SEB、SEC、SED和SEF的检出率分别为90.5%、6.9%、61.3%、5.2%和25.9%，未
检测出SEE基因。同时检出2种及2种以上的肠毒素基因的菌株有78株（67.2%），以携带SEA+SEC、SEA+SEF和SEA+SEC+
SEF基因为主，检出率分别为33.6%、7.8%和13.8%。与携带一种肠毒素基因的菌株耐药率相比，携带多种肠毒素基因的菌株耐
药率呈上升趋势，其中携带SEA+SEC+SEF的菌株对复方新诺明的耐药率为75.0%，高于单独携带SEA（28.6%）、SEA+SEC
（38.7%）的耐药率，具有统计学差异（P<0.05）。携带SEA+SEC+SEF、SEA+SEF、SEA的菌株对阿米卡星耐药率分别为75.0%、
77.0%和21.5%，前两者与携带SEA的菌株相比有显著差异（P<0.05）。结论临床分离的SA中携带多种肠毒素基因的菌株在耐
药率上高于只携带一种肠毒素基因的菌株，提示肠毒素在SA耐药中起重要作用。

Investigation of enterotoxin gene in clinical isolates of Staphylococcus aureus

Objective To detect the enterotoxin genes of Staphylococcus aureus(SA) isolated from clinical specimens and analyze the correlation between enterotoxin genes and drug resistance of SA.Methods The mecA gene and exterotoxin genes A-F of clinical SA isolates were identified by polymerase chain reaction(PCR),and the genes were sequenced to investigate the correlation of these genes to drug resistance.Results The detection rate of enterotoxin genes was 100% in 67 methicillin-resistant SA(MRSA),showing no significant difference from the rate in 57 methicillin-sensitive SA(MSSA)(83.5%,χ2=0.203,P>0.05).Of the 116 strains carrying enterotoxin genes(93.5%),the detection rates of SEA,SEB,SEC,SED and SEF were 90.5%,6.9%,61.3%,5.2%,25.9% and 93.5%,respectively,and none of the strains were positive for SEE gene.In these strains,78(67.2%) carried 2 or more enterotoxine genes,and the main genotypes were SEA and SEC(33.6%),SEA and SEF(7.8%),and SEA and SEC and SEF(13.8%).Compared with the strains carrying a single enterotoxin gene,those with multiple enterotoxin genes showed a higher drug resistance rate,among which 75% of the SA strains carrying SEA+SEC+SEF were resistant to SXT,significantly higher than the rates of SA carrying SEA(28.6%) and SEA+SEC(38.7%)(P<0.05).The SA strains carrying SEA+SEC+SEF and SEA+SEF showed significantly higher amikacin resistance rates than SA strain carrying SEA(75.0%,77.0%,21.5%,respectively,P<0.05).Conclusion Clinical isolates of SA carrying multiple enterotoxin genes have a higher drug resistance rate than those with a single enterotoxin gene,suggesting the the important role of enterotoxin in multidrug resistance.