校园周边熟食中金黄色葡萄球的分离及肠毒素基因检测

Isolation of Staphylococcus aureus from Cooked Food Samples around Campus and the Detection of Staphylococcal Enterotoxin Genes

了解校园周边熟食中金黄色葡萄球菌的污染及其肠毒素基因的分布情况。采集校园周边农贸市场及其路边小摊的熟食样品89份,采用国家标准GB4789.10-2016和PCR方法进行金黄色葡萄球菌分离鉴定;采用PCR方法对分离菌株进行21种肠毒素基因检测。结果表明共分离出71株金黄色葡萄球菌,样品中金黄色葡萄球菌的污染率为79.78%,其中,农贸市场和路边小摊的熟食污染率分别为80.70%(46/57)和78.12%(25/32);检测的21种肠毒素基因中,sec、see、seh、sel、sep和ses未检出,其他15种基因型被检出,包括3种传统肠毒素基因和12种新型肠毒素基因。71株金黄色葡萄球菌中,46株菌株检出携带肠毒素基因,检出率为64.78%(46/71)。46株携带肠毒素菌株中,sex检出率最高为86.96%(40/46),sei和sem为32.61%(15/46),sen和seo为30.43%(14/46),set为21.74%,seg为13.04%,sea、seb和ser为10.87%,sej和seu为6.52%,sek和seq为4.34%,sed为2.17%。通过本研究发现校园周边农贸市场及路边小摊的熟食中金黄色葡萄球菌污染率和肠毒素基因携带率均较高,新型肠毒素基因检测率高于传统肠毒素基因型,研究结果为金黄色葡萄球菌食品安全提供参考依据。

The contamination of Staphylococcus aureus and the distribution of staphylococcal enterotoxin genes in cooked food around campus were investigated in this study. A total of 89 food samples were collected from food markets and roadside stalls around campus. The distribution of 21 staphylococcal enterotoxin genes was detected by polymerase chain reaction(PCR) for all S. aureus food isolates. The results showed that seventy-one S. aureus strains were isolated and identified, with the total isolation rate of 79.78%. For market samples, the isolation rate was 80.70%; for roadside food stall samples, the isolation rate was 78.12%. Among 21 staphylococcal enterotoxin genes, sec, see, seh, sel, sep and ses genes were not detected. Other 15 types of genes, including 3 classical enterotoxin genes and 12 new enterotoxin genes, were detected. Forty-six(64.78%) S. aureus isolates carried one or more enterotoxin genes. Among them, 23 strains carried two or more enterotoxin genes, accounting for 50%. The detection rates of 21 staphylococcal enterotoxin genes in 46 enterotoxigenic S. aureus food isolates were as follows: sex(86.96%); sei and sem(32.61%); sen and seo(30.43%); set(21.74%); seg(13.04%); sea、ser and seb(10.87%), sej and seu(6.52%), sek and seq(4.34%), sed(2.17%). This study showed that the isolation rates of S. aureus strains and the detection rates of staphylococcal enterotoxin genes were very high in cooked food samples around campus. The genotypes of new enterotoxin were more than those of classical enterotoxins. This study provides a reference for staphylococcal food safety.