Antibiotic-resistant Escherichia coli Undergoes a Change in mcr-1 and qnr-S Expression after being Exposed to Gamma Irradiation

Abstract

Human consumption of antibiotics has increased their concentrations in many parts of the environment, including rivers, sediments, soil, and wastewater. Consequently, resistant bacteria originating from these environments are distributed to humans, resulting in illness. The aim of this study was to identify mobilized colistin-resistant (mcr) genes and quinolone-resistant (qnr) genes in E. coli strains obtained from clinical samples. Additionally, the study explored the impact of different radiation dosages on the expression of antibiotic-resistance genes. In this study, conducted in Beni-Suef, Egypt, samples from 430 community-acquired urinary tract infection (UTI) cases resulted in the isolation of 85 different strains of E. coli. Conventional microbiological procedures were employed to identify these bacterial isolates. Three bacterial isolates with resistance to both quinolones and colistin underwent examination for their corresponding genetic determinants, which subsequently proved the presence of their respective genes. Furthermore, the expression levels of the mcr-1 and qnr-S genes were assessed using real-time PCR after exposure to gamma irradiation. Remarkably, the use of a sublethal dosage of 3 kGy gamma irradiation treatment on bacterial cells increased their susceptibility to colistin and quinolones post-irradiation. Additionally, there was a notable reduction in the expression levels of both mcr-1 and qnr-S genes, which could be helpful for preventing the storage of antibiotic-resistant E. coli in the environment.