Yersinia pseudotuberculosis employs a multifaceted strategy to survive antimicrobials

Microbes have evolved a variety of strategies to survive exposure to naturally occurring and synthetic antimicrobials. These strategies have been investigated extensively in model bacterial organisms, whereas less is known about under explored pathogenic bacteria such as bacteria within the Yersinia genus. In this study we investigated the inhibitory effect and bactericidal activity of antibiotics from five different classes and of the disinfectant hydrogen peroxide against Yersinia pseudotuberculosis, the ancestral species from which Yersinia pestis and Yersinia enterocolitica have emerged. We found that Y. pseudotuberculosis is able to survive exposure to clinical antibiotics and disinfectants by employing a variety of strategies, with persisters and the Eagle effect playing a role in survival to quinolones, tolerance playing a role in survival to ceftriaxone and overexpression of catalases and peroxidases playing a role in survival to hydrogen peroxide. Our findings suggest that future research should focus on informing new, effective ways to treat infections caused by Yersinia species. IMPORTANCEAntimicrobial resistance is routinely investigated by measuring the minimum inhibitory concentration of antimicrobials needed to stop microbial growth. Here we show that the bacterial pathogen Yersinia pseudotuberculosis is not killed when antibiotics and disinfectants are used at these concentrations and that, in some cases, increasing antibiotic concentrations decreases their activity against this bacterium, therefore posing a potential risk to human and animal health.