Molecular detection of avian pathogenic Escherichia coli (APEC) in broiler meat from retail meat shop

Abstract

Avian pathogenic <i>Escherichia coli</i> (APEC) is a major bacterial pathogen responsible for the most widespread form of colibacillosis, resulting in substantial economic losses within the poultry sector and posing a potential public health risk. From July to September 2021, our study investigated the antibiotic resistance pattern of <i>Escherichia coli</i> (<i>E. coli</i>) and the presence of virulence-associated genes (<i>iucD</i>, <i>iutA</i>, <i>iss</i>, and <i>ompT</i>) linked to APEC using 105 broiler meat samples comprising liver, thigh, and breast muscle, in Chitwan, Nepal. <i>E. coli</i> was isolated and identified by culturing samples on MacConkey's agar, Eosin-methylene blue (EMB) agar and performing different biochemical tests. Antibiotic resistance patterns of <i>E. coli</i> were determined by the Kirby-Bauer disc diffusion method. Following the isolation of <i>E. coli</i>, the molecular detection of APEC was performed using conventional polymerase chain reaction (PCR). Out of the 105 samples analyzed, 61 (58.1 %) tested positive for <i>E. coli</i>. In antibiotic susceptibility test (AST), gentamicin and tetracycline exhibited the highest resistance rates, with 90.2 % and 67.2 %, respectively and 29.5 % of the <i>E. coli</i> isolates displayed multidrug-drug resistance. Out of 61 confirmed <i>E. coli</i> isolates, <i>iutA</i> was detected in 47 (77.0 %) samples, <i>iucD</i> in 46 (75.4 %), <i>iss</i> in 53 (86.8 %), and <i>ompT</i> in 39 (63.9 %) samples. This study reports the occurrence of MDR <i>E. coli</i> in meat samples, together with virulence genes associated with APEC which poses a public health threat. Continuous surveillance is vital for monitoring APEC transmission within poultry farms, coupled with efforts to raise awareness of food safety among consumers of broiler meat.