A survey of Chinese pig farms and human healthcare isolates reveals separate human and animal MRSA populations [article]

Geng Zou, Marta MATUSZEWSKA, Ming Jia, Jianwei ZHOU, Xiaoliang Ba, Juan DUAN, Caishi ZHANG, Jian ZHAO, Meng TAO, Jingyan Fan, Xiangming ZHANG, Wenping JIN (+17 others)
2021 bioRxiv   pre-print
There has been increasing concern that the overuse of antibiotics in livestock farming is contributing to the burden of antimicrobial resistance in people. Farmed animals in Europe and North America, particularly pigs, provide a reservoir for livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA, ST398) found in people. This study was designed to investigate the contribution of MRSA from Chinese pig farms to human infection and carriage. A collection of 603 S. aureus were
more » ... lated from 55 pig farms and 4 hospitals (MRSA= 285, 198; MSSA= 50, 70) in central China, a high pig farming density area, during 2017-2018. CC9 MRSA accounting for 93% of all farm MRSA isolates, while no was found in hospitals. ST398 isolates were found on three farms (n = 23) and three hospitals (n = 12). None of the ST398 from this study belong to the livestock clade of the LA-MRSA commonly found in Europe and North America. The hospital ST398 MRSA isolates formed a clade that was clearly separate from the farm ST398 MRSA and MSSA isolates, and all possessed human immune evasion cluster genes which were absent from all the pig farm ST398 isolates. Despite the presence of high levels of MRSA found on Chinese pig farms we found no evidence of them spilling over to the human population. Nevertheless, the ST398 MRSA obtained from human samples appear to be part of a widely distributed lineage in China. And the new animal adapted ST398 lineage that emerged in China should also be alarmed.
doi:10.1101/2021.08.02.454852 fatcat:qssbsx4ihzgr7lzzhpvj6njn2e