Next-Generation Sequencing Based Gut Resistome Profiling of Broiler Chickens Infected with Multidrug-Resistant Escherichia coli

SIMPLE SUMMARY: Antimicrobial resistance acquired an endemic status in the Pakistan poultry sector. A cross-sectional study was designed to investigate the fecal microbiome and resistome of broiler chickens infected with multidrug-resistant Escherichia coli using next-generation sequencing. Results show the widespread presence of diverse antibiotic resistance genes, virulence-associated genes, plasmid replicon types, and dysbiotic fecal microbial communities. Results indicate that antibiotic resistance altered the fecal microbial community structure of broiler chickens. The use of next-generation sequencing in this study documents a robust and cost-effective approach to study the fecal microbiome and resistome diversities of broiler chickens. ABSTRACT: The study was designed to investigate the fecal microbiome and resistome of broiler chickens infected with multidrug-resistant (MDR) Escherichia coli (E. coli). Fecal samples (n = 410) from broiler chickens were collected from thirteen randomly selected sites of Khyber Pakhtunkhwa and screened for the presence of MDR E. coli. Upon initial screening, thirteen (13) MDR E. coli isolates were then subjected to shotgun metagenome next-generation sequencing (NGS). NGS based resistome analysis identified the multidrug efflux pump system-related genes at the highest prevalence (36%) followed by aminoglycoside (26.1%), tetracycline (15.9%), macrolide-lincosamide-streptogramin (9.6%), beta-lactam (6.6%), rifampin (2%), sulphonamide (1.3%), phenicol (0.91%), vancomycin (0.62%), trimethoprim (0.34%), colistin (0.30%), and quinolone (0.33%). The most abundant virulence-associated genes (VAGs) identified were iroN, iutA, iss, and iucA. NGS based taxonomic profiling at the phylum level revealed the predominance of Proteobacteria (38.9%) followed by Firmicutes (36.4%), Bacteroidetes (15.8%), and Tenericutes (8.9%). Furthermore, pathobionts such as E. coli, Salmonella enterica, Klebsiella pneumoniae, and Shigella flexneri belonging to the family Enterobacteriaceae were predominantly found. This study revealed the widespread presence of MDR genes, diverse VAGs, and a dysbiotic gut in the broiler chickens infected with MDR E. coli of Khyber Pakhtunkhwa for the first time using NGS.