Characterization of ESBL producing gram negative uropathogenic bacteria isolated from patients with urinary yract infections from Mbeya, Tanzania

Abstract

Background: The emergence and spread of drug-resistant pathogens, such as ESBL-producing Gram-negative bacteria continue to threaten our ability to treat common infections causing a huge burden to our healthcare systems. Efforts to identify emerging pathogens or new pathogenic strains with their genetic markers that enhance their pathogenicity are needed. An understanding of antimicrobial resistance patterns and spread of resistance are also important to guide empirical treatment of common pathogens. This project aims to contribute scientific data that will help to address crucial issues on AMR. Objectives: This study aimed to characterize ESBL producing uropathogenic bacteria among the stored isolates obtained from clinically diagnosed patients with urinary tract infections. It determined the proportion of uropathogenic bacteria and their antimicrobial susceptibility pattern as well as identifying sequence types, plasmids, resistance and virulence genes in ESBL producing uropathogenic gram negative-bacteria isolates. Methods: This was a laboratory-based, descriptive cross-sectional study carried at the Catholic University of Health And Allied Sciences-Multipurpose Laboratory in Mwanza, Tanzania. Our analyses used 116 gram-negative isolates that were obtained from the HATUA study and archived at -80°C. Presumptive ESBL producing isolates were confirmed phenotypically by CLSI Combination Disc Diffusion and Modified Double Disc Synergy (MDDS) methods. Molecular characterization of ESBLs was done by Whole Genome Sequencing. Results: The proportion of uropathogenic gram negative bacteria was 61% (116/190) and Escherichia coli (E. coli) was the most isolated species. ESBL phenomenon was observed in 24% (20/83) of E. coli. We identified the sequence types ST617, ST131, *e4ac and ST3476 among the ESBL producing E. coli isolates that carried IncF and Col family of plasmids. The isolates possessed blaCTX-M-15, blaTEM-1B and blaOXA-1 genes for resistance and multiple virulence genes for adhesion, iron acquisition, capsule synthesis, evasion of immune response, toxin, survival in acidic conditions, and tellurite resistance. Conclusion: The phenotypic and genomic analysis of ESBL-producing Escherichia coli reveals a concerning presence of multidrug resistance, notably due to the presence of genes blaCTX-M-15, blaTEM-1B, and blaOXA-1. Additionally, the identified virulence factors and plasmids further underscore the potential for resistance to spread. These findings indicate a significant risk of disseminating multidrug-resistant strains, which poses a serious threat to public health.