Journal Article

Conserved phylogenetic distribution and limited antibiotic resistance of class 1 integrons revealed by assessing the bacterial genome and plasmid collection

Tiedje, James M., Zhang, Tong, Zhang, An Ni, Ma, Liping, Gillings, Michael R., Li, Li-Guan

2018

Overview

Background Integrons, especially the class 1 integrons, are major contributors to the acquisition and dissemination of antibiotic resistance genes (ARGs). However, comprehensive knowledge of the types, content, and distribution of integrons in bacterial taxa is lacking to evaluate their contribution. Results We have constructed a new integrase database and developed a pipeline that provides comprehensive recovery of class 1 integrons. Previous PCR-based techniques might only detect one fourth of the integron-integrases and integrons recovered in this study. By exploring the class 1 integrons in over 73,000 currently available complete and draft bacterial genomes, the contribution of class 1 integrons in spreading and acquiring ARGs was evaluated. Firstly, the host species of class 1 integrons are highly conserved within (96%) in class Gammaproteobacteria , dominated by four pathogenic species of “ESKAPE.” Secondly, more than half of class 1 integrons are embedded in chromosomes with less potential for horizontal gene transfer. Finally, ARGs that have been acquired by these integrons only cover 11% of all the ARG genotypes detected in bacterial genomes. Conclusions The above observations indicated that there are both biological and ecological limitations to class 1 integrons in acquiring and spreading ARGs across different classes of the domain Bacteria .

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Analysis / Anopheles / Antibiotic resistance / Antibiotics / Bacteria / Bacterial genetics / Bioinformatics / Biomedical and Life Sciences / Biomedicine / Chromosomes / Class 1 integrons / Database construction / Drug resistance / Drug resistance in microorganisms / Drug Resistance, Bacterial / Evolution, Molecular / Gammaproteobacteria - drug effects / Gammaproteobacteria - genetics / Gene transfer / Gene Transfer, Horizontal / Genes / Genome, Bacterial / Genomes / Genomics / Genotypes / Identification / Integrase / Integrons / Medical Microbiology / Microbial Ecology / Microbial Genetics and Genomics / Microbiology / Nonnative species / Phylogenetics / Phylogeny / Plasmids / Plasmids - genetics / Sequence Analysis, DNA / Software / Spreading / Studies / Virology / Whole genome analysis