生猪养殖环境及猪肉中金黄色葡萄菌肠毒素基因分布研究

Detection of staphylococcal enterotoxin genes in Staphylococcus aureus isolates from pig farms and commercial fresh pork

目的了解猪养殖场和市售生鲜猪肉分离的金黄色葡萄球菌的肠毒素基因携带情况。方法采用PCR方法检测sea、seb、sec、sed、see、seg、seh、sei、sej、sek、sel、sem、sen、seo、sep、seq、ser、seu 18个肠毒素基因在金黄色葡萄球菌中的分布状况。结果从130株金黄色葡萄球菌中,共检测到94.6%(123/130)的菌株携带有肠毒素基因,以seb的检出率最高,占60.8%,其中养殖场分离的金黄色葡萄球菌55%(55/100)、市售生鲜猪肉分离的金黄色葡萄球菌80%(24/30);养殖场分离株中检测到的肠毒素基因型主要有seb+seg+sem+sen、seg+sem、seg+sei+sem+sen、seg+sem+sen和seb+seg+sei+sem+sen,其检出率分别为8.0%(8/100)、7.0%(7/100)、7.0%(7/100)和6.0%(6/100);市售生鲜猪肉分离株中检测到的肠毒素基因型主要有sea+seb+see、sea+seb、seb+see和sea+see+sem,其检出率分别为30%(9/30)、10%(3/30)、10%(3/30)和6.7%(2/30)。养殖场和市售生鲜猪肉分离株中均未检测到sed、sej、seo、sep、seq、ser和seu基因。结论猪养殖场和市售生鲜猪肉分离的金黄色葡萄球菌均有携带肠毒素基因,且在型别上有一定的差异,可能存在不同的污染来源,这对监控猪养殖场和市售生鲜猪肉中金黄色葡萄球菌的污染及肠毒素基因的携带状况具有一定意义。

The aim of this study is to investigate the prevalence of staphylococcal enterotoxin genes profile of Staphylococcus aureus in pig farms samples and commercial fresh pork.Totally 18 enterotoxin genes（sea,seb,sec,sed,see,seg,seh,sei,sej,sek,sel,sem,sen,seo,sep,seq,ser,seu）were detected in S.aureus by PCR.Of 130 S.aureus,94.6%（123/130）isolates were positive for enterotoxin genes,including 55%（55/100）isolates from pig farms samples and 80%（24/30）isolates from commercial fresh pork.The highest positive rate of seb account for 60.8% among 18 enterotoxin genes.The main toxins gene profiles were detected in S.aureus from pig farms samples were seb＋seg＋sem＋sen,seg＋sem,seg＋sei＋sem＋sen,seg＋sem＋sen and seb＋seg＋sei＋sem＋sen,and their positive rates were 8.0%（8/100）,7.0%（7/100）,7.0%（7/100）and6.0%（6/100）respectively.The main toxins gene profiles were detected in S.aureus from commercial fresh pork were sea＋seb＋see,sea＋seb,seb＋see and sea＋see＋sem,and their positive rates were 30%（9/30）,10%（3/30）,10%（3/30）and 6.7%（2/30）respectively.Neither sed,sej,seo,sep,seq,ser or seu genes were detected in 130 S.aureus.S.aureus were isolated from pig farms and commercial fresh pork carrying toxin genes,and the toxins gene profiles were different,there may be different pollution sources.Our findings has certain significance for monitoring the status of S.aureus pollution and the distribution of toxin genes in pig farms and commercial fresh pork.