Genotypic diversity of staphylococcal enterotoxin B gene (seb) and its association with molecular characterization and antimicrobial resistance of Staphylococcus aureus from retail food

• Published in: International journal of food microbiology 2024-01, Vol.408, p.110444-110444, Article 110444
• Main Authors: Zhang, Pengfei, Zhang, Yao, Ruan, Fuqian, Chang, Guanhong, Lü, Zexun, Tian, Lei, Ji, Hua, Zhou, Ting, Wang, Xin
• Format: Article
• Language: English
• Subjects: Antimicrobial resistance; Molecular characterization; Staphylococcal enterotoxin B (SEB); Staphylococcus aureus
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/j.ijfoodmicro.2023.110444

To investigate the expression pattern of staphylococcal enterotoxin B (SEB) in food and the genotypic diversity of SEB-encoding gene in association with molecular characteristics and antimicrobial resistance of S. aureus, 498 isolates from retail food were screened for seb gene and detected for SEB production in S. aureus. In addition, the seb nucleotide sequences, virulence genes, resistance genes, antimicrobial susceptibility and molecular characteristics of S. aureus were examined. A total of 45 (9.0 %) seb-positive S. aureus strains were identified, all of which expressed SEB. The detection rate of SEB-production strains was significantly higher from dairy-related sources than those from other sources (P  0.05) in SEB production between SEB1 and SEB2 genotyping strains. Based on MLST clustering analysis, the same molecular type strains were found to have the same SEB genotyping, virulence gene profile, resistance gene profile and drug resistance profile. Among them, the dominant molecular types of SEB1 and SEB2 strains were CC1-ST188-t189 and CC59-ST59-t437, respectively. Compared to the CC1-ST188-t189 clonal strain, the CC59-ST59-t437 clonal strain carried a higher number of virulence and resistance genes and exhibited a broader resistance profile. Therefore, understanding the characteristics of the strains and their expression patterns in food can be effective in preventing food poisoning incidents. •Higher level SEB-producing S. aureus contamination existed in dairy-related samples than in pork, chicken, and egg.•Two different SEB genotypes were identified, with 4 different amino acids between SEB1 and SEB2.•CC1-ST188-t189 and CC59-ST59-t437 were the dominant clone SEB1 and SEB2 strains, respectively.•Compared to the CC1-ST188-t189 clonal strain, the CC59-ST59-t437 clonal strain carried a higher number of virulence and resistance genes and exhibited a broader resistance profile.