A search for new mechanisms to inhibit plasmid conjugation

Abstract

Infections due to antibiotic-resistant (AbR) bacteria are a major cause of morbidity and mortality throughout the world. In addition, the number of new antibiotics being developed has plummeted. Although resistance genes can disseminate by any horizontal gene transfer mechanism, the vast majority of reports of bacterial gene transfer in the environment involve conjugation. Our group developed a method for high-throughput analysis of conjugation. This method was used to check for host genes in the recipient cell involved in conjugation, concluding that lab strains of Escherichia coli like DH5[alfa] have no non-essential genes that play an essential role in conjugation. In recipient cells, conjugation can be inhibited by different mechanisms: restriction systems, CRISPRs, entry exclusion systems or incompatibility, among others. Our aim is to screen a set of natural plasmids to look for conjugation broad-range inhibitor genes in enterobacterial plasmids, in order to hopefully identify new mechanisms of inhibition that could be used to control AbR propagation.