预制食品中金黄色葡萄球菌的分布、毒力及耐药性分析

Distribution, Virulence, and Antibiotic Resistance of Staphylococcus aureus in Prefabricated Foods

摘要:

【目的】探究市售预制食品中金黄色葡萄球菌的污染分布、分离菌株的毒力基因携带情况及药敏性。【方法】依据GB 4789.10—2016，对佛山市某地区的市售预制食品进行金黄色葡萄球菌检测，采用聚合酶链式反应（polymerase chain reaction，PCR）检测分离菌株的毒力基因，使用纸片扩散法和PCR反应分析菌株的药敏性及耐药基因携带情况。【结果】预制食品样本中金黄色葡萄球菌平均检出率为13.1%，其中，预制肉类检出率最高（24.3%）；85.7%的金黄色葡萄球菌阳性样本污染水平<1.0×10³ CFU/g。阳性样本中共分离获得14株高血浆凝固酶活性的金黄色葡萄球菌代表菌株，分离菌株的pvl检出率（100.0%）最高，其次为hla（78.6%）、sea（71.4%）、hlb（28.6%）和seb（14.3%），78.5%的菌株同时携带3种以上毒力基因。菌株普遍对青霉素耐药（78.6%），3株菌株具有多重耐药性。耐药表型与耐药基因关联性良好，耐药基因mecA检出率（21.4%）最高。【结论】肉类预制食品中金黄色葡萄球菌检出率较高，多数菌株同时携带多种毒力基因，少数菌株具有多重耐药性，需加强对预制食品中金黄色葡萄球菌的风险监测。

Abstract:

[Objective]This study aimed to investigate the distribution of Staphylococcus aureus (S. aureus) in prefabricated foods and the virulence genes and antibiotic resistance of isolated strains.[Method]S. aureus in commercial prefabricated foods sampled from Foshan City was detected according to the national standard GB 4789.10—2016. The virulence genes were detected by polymerase chain reaction (PCR). The antibiotic resistance and antibiotic resistance genes of isolated strains were characterized by the disk diffusion method and PCR.[Result]The average detection rate of S.aureus in samples of prefabricated foods was 13.1%, with meat products possessing the highest positive rate (24.3%). A total of 85.7% of positive samples had S. aureus contamination levels less than 1.0×10³ CFU/g. A total of 14 representative strains of S. aureus with high plasma coagulase activity were isolated from positive samples. Among the virulence genes, pvl had the highest detection rate (100.0%), followed by hla (78.6%), sea (71.4%), hlb (28.6%), and seb (14.3%), and 78.5% strains carried more than 3 virulence genes. Most strains were resistant to penicillin (78.6%), and 3 strains exhibited multi-drug resistance. The antibiotic resistance genes showed strong associations with the phenotypes, with mecA exhibited the highest detection rate of 21.4%.[Conclusion]S.aureus contamination in prefabricated foods presents mainly in meat products. Most of the isolated strains simultaneously carry multiple virulence genes, while a few strains exhibit multi-drug resistance. Therefore, it is of great importance for monitoring S. aureus in prefabricated foods.