Targeted inactivation of multidrug-resistant Alcaligenes faecalis in pig farm WWTPs by mixed bacteriophages to diminish the risk of pathogenicity and antibiotic resistance dissemination

Wastewater treatment plants (WWTPs) at pig farms are significant environmental reservoirs of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs). In particular, contamination by multidrug-resistant Alcaligenes faecalis (MDR-AF) poses an increasingly severe threat to human health. However, no safe and effective method is currently available to hinder its dissemination in the environment. In this study, two hitherto unreported bacteriophages were screened. In addition, qPCR experiments demonstrated that applying these bacteriophage preparations to wastewater significantly eradicates MDR-AF and reduces ARGs by 0.7-2.5 orders of magnitude (P < 0.05), thereby substantially diminishing the risk of antibiotic resistance transmission. Furthermore, various characterizations, bacteriophage genomic analysis, and microbial community analysis indicated that these bacteriophage preparations possess safety, specificity, and high resilience, rendering them an efficient and eco-friendly biological control measure.