Isolation and Characterization of Extended-Spectrum β-Lactamase Producing Escherichia coli from Pig Farms and Slaughterhouse

Extended-spectrum beta-lactamase (ESBL) producing Escherichia coli represents a formidable challenge in the field of microbiology and public health due to its resistance to commonly used antibiotics. These strains pose a serious threat to human and animal health, underscoring the urgency of comprehensive research and surveillance. The ongoing investigation seeks ESBL producing E. coli strains from pig farms and slaughterhouses in West Bengal and Assam, India. A total of 309 samples were collected: nasal swabs (25), rectal swabs (25) from healthy pigs, pig pen soil (45), faeces (55), slaughterhouse effluents (115), and cleaning water (44). In these samples, 154 tested positive for E. coli, indicating a 49.8% prevalence. Among 154 E. coli isolates, 23 (14.9%) produced ESBLs, sourced from pig rectal swabs (7.1%), faeces (10.7%), slaughterhouse effluents (26.1%), and cleaning water (11.7%). Significantly, 4 ESBL E. coli isolates (6.6%) exclusively emerged from pig slaughterhouse effluents, displaying imipenem-resistant properties. The majority of ESBL E. coli primarily produced CTX-M and CMY, with consistent genetic markers blaCTX-M (100%) and blaCMY (82.6%). Remarkably, 2 (8.6%) of 17 ESBL E. coli isolates from pig slaughterhouse effluents carried the genetic marker blaNDM1. These findings stress implementing thorough surveillance in pig farms and local slaughterhouses. This proactive approach is crucial to identify ESBL E. coli strains, enhancing public health protection.