生鲜乳中金黄色葡萄球菌检测及性状分析

Prevalence and characterization of Staphylococcus aureus isolated from raw milk

对天津市周边9家奶场原料奶中金黄色葡萄球菌污染水平、肠毒素基因的携带情况及耐药性进行调查研究。采集原料奶样品共432份,按照GB4789.10-2010对原料奶中金黄色葡萄球菌进行检验,并对筛选出来的金黄色葡萄球菌进行肠毒素基因研究、生物膜形成能力分析和耐药性分析。结果表明:采集的432份原料奶中,金黄色葡萄球菌阳性样本有14个,阳性率为3.24%,筛选出来的14株金黄色葡萄球菌携带SEA的概率为100%;14株菌中有10株分离株可以形成生物膜,其中2株可以形成中等粘附的生物膜;金黄色葡萄球菌分离株对氯霉素耐药率(100%)最高,对头孢西丁钠(21.43%)、阿米卡星(14.29%)、万古霉素(14.28%)、苯唑西林(28.57%)耐药率较高,所有菌株对环丙沙星敏感。其中有4株分离株为多重耐药株。结论:所选取的9家奶厂中,原料奶中金黄色葡萄球菌污染率相对较低,但金黄色葡萄球菌分离株肠毒素A基因检出率较高,生物膜形成能力较强,耐药情况比较严重,并且存在多重耐药和万古霉素耐药菌株,本研究为奶源性金黄色葡萄球菌的污染溯源和控制提供了相应的数据支持。

To investigate the contamination and enterotoxin of Staphylococcus aureus in raw milk from 9 dairy farms around Tianjin city, to un- derstanding the dairy product safety. 432 raw milk were collected, according to GB4789.10-2010, the contamination of Staphylococcus aure- us were detectedand the analysis of Staphylococcus aureus enterotoxin gene and biofilm formation ability and the antibiotic resistance were carried out. Results： Staphylococcus aureus was detected in 14 raw milk samples, with a total detection ratio of 3.24%. The detection ratio ofen- terotoxin gene A of Staphylococcus aureus was 100%. In this experiment, 14 Staphylococcus aureus were isolated, in which 10 strains have the abili- ty of forming biofilm. For the Staphylococcus aureus isolated from milk, the highest drug-resistance of all strain was chloramphenicol （100%）, many isolates were resistant to cefoxitin （21.43%）, amikacin （14.29%）, vancomycin （14.28%）, oxacillin （28.57%）, all the isolates were suscepti- ble to ciprofloxacin. 4 isolates were multi-drug resistance.Conclusion： The Staphylococcus aureus pollution was not very serious in raw milk in Tianjin city. But the isolates of Staphylococcus aureus enterotoxin and biofilm forming ability is not optimistic. In addition, there were mukiple drug resistance and vancomycin resistant strains. This study provided the supporting data for control pollution traceability of Staphylococcus aure- US.