Disinfectants facilitate the transformation of exogenous antibiotic resistance genes via multiple pathways

The prevalence and spread of multidrug-resistant (MDR) bacteria pose a global challenge to public health. Natural transformation is one of the essential ways for horizontal transfer of antibiotic resistance genes (ARGs). Although disinfectants are frequently used during COVID-19, little is known about whether these disinfectants are associated with the transformation of plasmid-borne ARGs. In our study, we assessed the effect of some disinfectants on bacterial transformation using resistance plasmids as extracellular DNA and E. coli DH5 alpha as the recipient bacteria. The results showed that these disinfectants at environmentally relevant concentrations, including benzalkonium bromide (BB), benzalkonium chloride (BC) and polyhexamethylene guanidine hydro-chloride (PHMG), significantly enhanced the transformation of plasmid-encoded ARGs. Furthermore, we investigated the mechanisms underlying the promotive effect of disinfectants on transformation. We revealed that the addition of disinfectants significantly increased the membrane permeability and promoted membrane-related genes expression. Moreover, disinfectants led to the boosted bacterial respiration, ATP production and flagellum motility, as well as increased expression of bacterial secretion system-related genes. Together, our findings shed insights into the spread of ARGs through bacterial transformation and indicate potential risks associated with the widespread use of disinfectants.

Automated summary

The prevalence and spread of multidrug-resistant bacteria is a global challenge to public health. This study assessed the effect of certain disinfectants on bacterial transformation and found that these disinfectants significantly enhanced the transformation of plasmid-encoded antibiotic resistance genes. The study also revealed the mechanisms underlying the promotive effect of disinfectants on transformation. These findings provide new insights into the spread of antibiotic resistance genes through bacterial transformation and indicate potential risks associated with the widespread use of disinfectants.