Escherichia coli and Salmonella spp. isolated from Australian meat chickens remain susceptible to critically important antimicrobial agents

• DOI: 10.1371/journal.pone.0224281
• Publication Date: 2019-10-23T17:51:54Z
• Authors: Sam Abraham; Mark O’Dea; Shafi Sahibzada; Kylie Hewson; Anthony Pavic; Tania Veltman; Rebecca Abraham; Taha Harris; Darren J. Trott; David Jordan
• Keywords: 2. Zero hunger; Meat; Whole Genome Sequencing; Science; Q; R; Australia; 630; Anti-Bacterial Agents; 3. Good health; Salmonella; Drug Resistance, Bacterial; Escherichia coli; Food Microbiology; Medicine; Animals; Chickens; Research Article

The World Health Organisation has defined "highest priority critically important antimicrobials" (CIAs) as those requiring the greatest control during food production. Evidence demonstrating that restricted antimicrobial usage prevents emergence of resistance to CIA's amongst pathogenic and commensal organisms on a production system-wide scale would strengthen international efforts (AMR). Therefore, in designed survey all major chicken-meat producers Australia, we investigated phenotypic AMR E. coli (n = 206) Salmonella 53) from caecal samples chickens at slaughter 200). A large proportion isolates (63.1%) were susceptible tested antimicrobials. With regards CIA resistance, only two E.coli demonstrated fluoroquinolones, attributed mutations quinolone resistance-determining regions gyrA. Antimicrobial was observed for trimethoprim/sulfamethoxazole (8.7%), streptomycin (9.7%), ampicillin (14.1%), tetracycline (19.4%) cefoxitin (0.5%). All ceftiofur, chloramphenicol, ciprofloxacin, colistin, florfenicol, gentamicin tetracycline. low frequency exhibited (1.9%), (3.8%), (11.3%). among Sofia serovars. None multi-class-resistant phenotype. Whole genome sequencing did not identify any known mechanisms cefoxitin. results provide strong evidence highest is absent isolated Australian meat chickens, demonstrates levels compounds with less critical ratings such cefoxitin, trimethoprim/sulfamethoxazole, Apart regulated exclusion CIAs most aspects livestock production, vaccination against key bacterial pathogens stringent biosecurity are likely have contributed favorable status chicken industry. Nevertheless, industry government need proactively monitor stewardship practices ensure long-term protection both animal human health.