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

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.