Influence of antibiotic resistance on disinfectant tolerance of Escherichia coli, Staphylococcus aureus, Enterococcus faecium and Campylobacter jejuni.

Antimicrobial-resistant (AMR) bacteria are an increasing concern for human and animal medicine. As a result, biosecurity measures such as cleaning and disinfection are becoming heavily relied upon to eradicate and control AMR pathogens. However, evidence of co- and cross-resistance between antimicrobials and disinfectants is rising. The influence of AMR on disinfectant tolerance is poorly understood for pathogens of veterinary and public health importance. Therefore, this study aimed to compare disinfectant tolerance of fluoroquinolone-resistant Campylobacter jejuni, livestock-associated methicillin-resistant Staphylococcus aureus, multi-drug-resistant Escherichia coli and vancomycin-resistant Enterococcus faecium, with their antibiotic-susceptible counterparts. In vitro disinfectant efficacy was assessed, in the presence of organic matter, against a panel of eight disinfectants from six classes. The disinfectant efficacy varied widely depending on bacterial species and disinfectant class. Furthermore, approved disinfectant concentrations were not always deemed effective. All four bacterial species were typically most susceptible to aldehyde and/or quaternary ammonium compound-based products. Mixed evidence was found to suggest a role of AMR in disinfectant tolerance; no role of AMR was identified in E. coli, C. jejuni or E. faecium, whereas a potential role was identified in S. aureus.