Broiler house environment and litter management practices impose selective pressures on antimicrobial resistance genes and virulence factors ofCampylobacter

Abstract

Campylobacterinfections are a leading cause of bacterial diarrhea in humans globally. Infections are due to consumption of contaminated food products and are highly associated with chicken meat, with chickens being an important reservoir forCampylobacter. Here, we characterized the genetic diversity ofCampylobacterspecies detected in broiler chicken litter over three consecutive flocks and determined their antimicrobial resistance and virulence factor profiles. Antimicrobial susceptibility testing and whole genome sequencing were performed onCampylobacter jejuni(n = 39) andCampylobacter coli(n = 5) isolates. AllC. jejuniisolates were susceptible to all antibiotics tested whileC. coli(n =4) were resistant to only tetracycline and harbored the tetracycline-resistant ribosomal protection protein (TetO). Virulence factors differed within and across grow houses but were explained by the isolates' flock cohort, species and multilocus sequence type. Virulence factors involved in the ability to invade and colonize host tissues and evade host defenses were absent from flock cohort 3C. jejuniisolates as compared to flock 1 and 2 isolates. Our results show that virulence factors and antimicrobial resistance genes differed by the isolates' multilocus sequence type and by the flock cohort they were present in. These data suggest that the house environment and litter management practices performed imposed selective pressures on antimicrobial resistance genes and virulence factors. In particular, the absence of key virulence factors within the final flock cohort 3 isolates suggests litter reuse selected forCampylobacterstrains that are less likely to colonize the chicken host.

Pseudomonas aeruginosa strain CD3 implements cadmium resistance through multimodal systems and its regulatory networking

“…In such circumstances, natural selection supports individuals with mutations or gene acquisitions that offer metal resistance. In the course of time, these favourable traits present frequently within the population contribute to the advent of cadmium-resistant bacterial strains (Woyda et al 2023).…”