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目的了解宁波市食源性金黄色葡萄球菌(S.aureus)肠毒素基因分布和分子分型特征。方法收集2005—2012年宁波市食品中金黄色葡萄球菌菌株,利用聚合酶链式反应(PCR)检测肠毒素A、B、C和D基因(sea,seb,sec和sed),对肠毒素基因阳性菌株利用多位点序列分型(MLST)进行分子分型。结果 2005—2012年共分离菌株190株,肠毒素基因阳性菌株为41株,阳性率为21.58%。4种肠毒素基因阳性率分别为7.37%(14/190)、5.26%(10/190)、8.95%(17/190)和5.79%(11/190),其中13株菌株具有两个及两个以上肠毒素基因。41株菌株可分为12个序列型(ST),以ST5、ST6、ST188和ST1为主,共占75.61%(31/41),在进化树上主要形成4个分支。结论 2005—2012年宁波市食品中金黄色葡萄球菌携带肠毒素基因频率较高,需加强监测。肠毒素基因阳性菌株与中国其他地区食品株在分子分型上存在较大差异。
Objective To understand the gene distribution and molecular typing characteristics of food-borne Staphylococcus aureus (S. aureus) in Ningbo. Methods The Staphylococcus aureus strains in food from 2005 to 2012 in Ningbo were collected and the enterotoxin A, B, C and D genes (sea, seb, sec and sed) were detected by polymerase chain reaction (PCR) Positive strains were genotyped by multilocus sequence typing (MLST). Results A total of 190 isolates and 41 enterotoxin-positive isolates were isolated from 2005 to 2012, the positive rate was 21.58%. The positive rates of the four kinds of enterotoxin genes were 7.37% (14/190), 5.26% (10/190), 8.95% (17/190) and 5.79% (11/190) respectively, of which 13 strains had two and two Or more enterotoxin genes. 41 strains were divided into 12 sequences (ST), mainly ST5, ST6, ST188 and ST1, accounting for 75.61% (31/41) in total, and mainly formed 4 branches in the evolutionary tree. Conclusion In 2005-2012, Staphylococcus aureus in the city of Ningbo carried a high frequency of enterotoxin-associated genes and surveillance was needed. Enterotoxin gene-positive strains and other parts of China’s food strains in molecular typing there is a big difference.