Animal Husbandry and Feed Science ›› 2025, Vol. 46 ›› Issue (5): 1-9.doi: 10.12160/j.issn.1672-5190.2025.05.001

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Contamination Characteristics of mcr Genes and ESKAPE Pathogens in Pig Farm Wastewater Surrounding Poyang Lake

YANG Lili1, XIAO Guangming2, WANG Zhong1, WANG Wang1, WANG Liqi1   

  1. 1. College of Animal Science, Guizhou University, Guiyang 550025, China;
    2. Huaxi District Agriculture and Rural Affairs Bureau, Guiyang 550025, China
  • Received:2025-05-21 Published:2025-12-25

Abstract: [Objective] To investigate the contamination characteristics of ESKAPE pathogens and the mobilized colistin resistance gene (mcr gene) in pig farm wastewater surrounding Poyang Lake. [Methods] Nineteen wastewater samples were collected from 11 pig farms near Poyang Lake. Metagenomic sequencing technology was used to determine the relative abundance of ESKAPE pathogens and mcr genes, followed by Pearson correlation analysis. [Results] A total of 26 types of mcr genes and mutants were detected in the 19 wastewater samples, with 8 to 19 types detected per sample; five ESKAPE pathogens were detected, including Pseudomonas aeruginosa, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, and Enterococcus faecium. Comparing the removal rates of mcr genes before and after wastewater treatment showed that 12 types of mcr genes decreased in all farms where removal rates could be calculated (removal rates 56.0%-100%) and 12 other genes (excluding mcr-4.3 and mcr-3.6) decreased in some farms but increased in others (increase rates 22.2%-8,500.0%). Both P. aeruginosa and K. pneumoniae showed a significant positive correlation with the mcr-2 and mcr-3 genes (P<0.05). [Conclusion] ESKAPE pathogens and mcr gene contamination are present in pig farm wastewater surrounding Poyang Lake, and Gram-negative ESKAPE pathogens may carry mcr genes. The existing wastewater treatment methods are insufficient to effectively remove mcr genes, thereby increasing the environmental health risks associated with pig farm wastewater. The findings provide a reference for strengthening manure management at pig farms near Poyang Lake and improving the quality of the farming ecological environment.

Key words: mcr gene, ESKAPE pathogens, resistance gene, pig farm wastewater, surrounding area of Poyang Lake

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