AUTHOR=Guo Yahui , Yu Xiaojie , Wang Jixiao , Hua De , You Yuanhai , Wu Qingbo , Ji Qinglong , Zhang Jianzhong , Li Liefei , Hu Yuan , Wu Zhonghui , Wei Xiaoyue , Jin Lianqun , Meng Fanliang , Yang Yuhua , Hu Xiaofeng , Long Lijin , Hu Songnian , Qi Heyuan , Ma Juncai , Bei Wenwen , Yan Xiaomei , Wang Haibin , He Zilong 

TITLE=A food poisoning caused by ST7 Staphylococcal aureus harboring sea gene in Hainan province, China

JOURNAL=Frontiers in Microbiology

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1110720

DOI=10.3389/fmicb.2023.1110720

ISSN=1664-302X

ABSTRACT=<p>ST7 <italic>Staphylococcus aureus</italic> is highly prevalent in humans, pigs, as well as food in China; however, staphylococcal food poisoning (SFP) caused by this ST type has rarely been reported. On May 13, 2017, an SFP outbreak caused by ST7 <italic>S. aureus</italic> strains occurred in two campuses of a kindergarten in Hainan Province, China. We investigated the genomic characteristics and phylogenetic analysis of ST7 SFP strains combined with the 91 ST7 food-borne strains from 12 provinces in China by performing whole-genome sequencing (WGS). There was clear phylogenetic clustering of seven SFP isolates. Six antibiotic genes including <italic>blaZ, ANT (4′)-Ib, tetK, lnuA, norA,</italic> and <italic>lmrS</italic> were present in all SFP strains and also showed a higher prevalence rate in 91 food-borne strains. A multiple resistance plasmid pDC53285 was present in SFP strain DC53285. Among 27 enterotoxin genes, only <italic>sea</italic> and <italic>selx</italic> were found in all SFP strains. A ФSa3int prophage containing type A immune evasion cluster (<italic>sea, scn, sak</italic>, and <italic>chp</italic>) was identified in SFP strain. In conclusion, we concluded that this SFP event was caused by the contamination of cakes with ST7 <italic>S. aureus</italic>. This study indicated the potential risk of new emergencing ST7 clone for SFP.</p>