High carriage and possible hidden spread of multidrug-resistant Salmonella among asymptomatic workers in Yulin, China
Xin Lu, Ming Luo, Mengyu Wang, Zhemin Zhou, Jia‐Liang Xu, Zhenpeng Li, Peng Yao, Yuan Zhang, Fangyu Ding, Dong Jiang, Changyu Zhou, Liya Yang, Wenxuan Zhao, Tian Ma, Bo Pang, Meiying Yan, Yongning Wu, Yannong Wu, Biao Kan, Yannong Wu, Biao Kan
Abstract
Food workers have frequent contact with unprocessed foods, but their carriage of Salmonella and potential influence on public health have not been comprehensively assessed. We investigated Salmonella carriage among food workers compared with non-food workers based on occupational health screening of 260,315 asymptomatic workers over an 8-year surveillance period in Yulin, China. We confirmed that healthy carriers serve as natural reservoirs for Salmonella, with higher carriage rates in food workers than non-food workers. The isolates from food workers also exhibited greater serovar diversity and likely higher levels of antimicrobial resistance than those from non-food workers. Factors such as meteorological, social, and hygiene factors potentially influenced the carriage rate. Genomic analysis revealed a consistent increase in antimicrobial resistance genes among Salmonella isolates over the study period, with the majority of these antimicrobial resistance genes located on plasmids. Additionally, we identified numerous closely related bacterial clusters, which might reflect clusters of hidden local foodborne infections. This study underscores the elevated risk posed by food workers in the persistence and dissemination of Salmonella as vectors/fomites. Enhanced monitoring and targeted interventions in this group may reduce the dissemination of pathogens and antimicrobial resistance genes. Salmonella is a significant cause of gastrointestinal infection and asymptomatic carriage can contribute to transmission. Here, the authors investigate the prevalence of asymptomatic carriage of Salmonella in Yulin, China through occupational health screening and find that carriage was higher in food workers.