Sub-lethal photocatalysis promotes horizontal transfer of antibiotic resistance genes by conjugation and transformability

• Published in: Water research (Oxford) 2022-08, Vol.221, p.118808-118808, Article 118808
• Main Authors: Ji, Hao, Cai, Yiwei, Wang, Zaixia, Li, Guiying, An, Taicheng
• Format: Article
• Language: English
• Subjects: Antibiotic-resistant bacteria; ARGs transfer mechanism; Conjugative transfer; Sub-lethal photocatalysis; Transformation
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2022.118808

•Horizontal ARG transfer in water could be facilitated by sub-lethal photocatalysis.•Conjugative transfer could be affected by bacterial stress response and vitality.•The horizontal gene transfer of ARG was dependent on ATP activity of ARB.•Extracellular plasmids produced by sub-lethal photocatalysis were transformable. The spread of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in water is increasingly becoming a worldwide problem due to frequent recent major public health events. Herein, the horizontal ARG transfer mechanisms were studied under sub-lethal photocatalysis. The results show that ARGs had at most a 3- to 6-fold increase in the conjugative transfer frequency when only donor bacteria were induced with sub-lethal photocatalysis, while the frequency exhibited a trend toward inhibition when only the recipient bacteria were induced. However, when the donor or recipient bacteria were induced beforehand for a specific time, the frequency increased by a maximum of 10- to 22-fold. Moreover, the horizontal transfer frequency and its mechanism were related to the oxidative stress systems, ATP systems and the expression of related genes. Furthermore, the transformability of extracellular plasmids of the ARB and the contribution in horizontal transfer were also studied. Results show that the transformation frequency accounted for up to 50% of the total number of transconjugants, indicating that transformation might be a primary mode of horizontal ARG transfer by ARB in water. All of the above results demonstrate that sub-lethal photocatalysis will increase the frequency of horizontal gene transfer of ARGs through both conjugative transfer and the transformation pathway, which increases the risk of ARB in aquatic environments. [Display omitted]