Antibiotic Resistance and Virulence of Extraintestinal Pathogenic (ExPEC) Vary According to Molecular Types.

Extraintestinal pathogenic (ExPEC) can cause many human extraintestinal infections. Resistance and virulence of ExPEC are inextricably linked to its phylogenetic background. However, studies on type-specific distribution of resistance and virulence and the connection between resistance/virulence and molecular typing are lacking. Here, 411 ExPEC strains were collected and characterized using antimicrobial susceptibility testing and molecular typing. Among these, 74 representative strains were selected for whole genome sequencing and the killing assay. CH40-30-ST131, CH37-27-ST405, CH40-41-ST131, and CH13-5-ST12 isolates had high resistance rates to all antimicrobials tested. played a significant role in the β-lactam resistance of ExPEC isolates. CH14-64-ST1193, CH40-30-ST131, and CH35-27-ST69 isolates were highly virulent in the model. Virulence factors (VFs) involved in adherence (, , , and ), autotransporter (), invasion (, ), iron uptake (except for ), or toxin () might be responsible for pathogenicity . Specific antibiotic resistance genes (ARGs) or VFs were prevalent in specific types of strains, including , , , , , , and aerobactin genes in CH14-64-ST1193 isolates; , , , , , , , , , , and in CH40-30-ST131 isolates; in CH35-27-ST69 and CH13-5-ST12 isolates. Type distribution also differed by VF score. CH37-27-ST405 and CH26-5-ST38 isolates carried more ARGs and VFs indicating that they had a high resistance and virulence potential. This study demonstrates the type-specific distribution of resistance and virulence thus providing a basis for further research, prevention and treatment of ExPEC infections.