Integrons, transposons and IS elements promote diversification of multidrug resistance plasmids and adaptation of their hosts to antibiotic pollutants from pharmaceutical companies

Abstract

Plasmids are important vehicles for the dissemination of antibiotic resistance genes (ARGs) among bacteria by conjugation. Here, we determined the complete nucleotide sequences of nine different plasmids previously obtained by exogenous plasmid isolation from river and creek sediments and wastewater from a pharmaceutical company. We identified six IncP/P-1ε plasmids and single members of IncL, IncN and IncFII-like plasmids. Genetic structures of the accessory regions of the IncP/P-1ε plasmids obtained implied that multiple insertions and deletions had occurred, mediated by different transposons and Class 1 integrons with various ARGs. Our study provides compelling evidence that Class 1 integrons, Tn402-like transposons, Tn3-like transposons and/or IS26 played important roles in the acquisition of ARGs across all investigated plasmids. Our plasmid sequencing data provide new insights into how these mobile genetic elements could mediate the acquisition and spread of ARGs in environmental bacteria.

Graphical Abstract

Plasmids are the carriers of antibiotic resistance genes (ARGs). We have deciphered the complete nucleotide sequences of nine unique plasmids in pharmaceutical wastewater and aquatic environments. These tiny molecular machines are cleverly equipped with integrons and transposons, enabling the acquisition and transfer of diverse ARGs. Our findings shed light on how these genetic elements facilitate the spread of resistance among bacteria in both environmental and public health settings, with significant implications for combating drug-resistant infections.