Characterization of antibiotic-resistant Escherichia coli associated with urinary tract infections in Southern Colombia

Abstract

Bacterial resistance to antibiotics is one of the largest medical concerns worldwide. One of the bacteria of critical priority is E. coli, since it presents different resistance mechanisms and some of its strains have evolved resistance to beta-lactam antibiotics. We characterized 32 antibiotic resistant bacterial isolates from confirmed cases of urinary tract infections from an array of patients in Nariño, southern Colombia. Macro and microscopic descriptions of the 32 clinical isolates were conducted. Resistance profiles, biochemical, and molecular characterization (via 16S rRNA gene sequencing, ERIC-PCR, and resistance genes) were performed. All the isolates were identified as E. coli and had resistance to beta-lactams, aminoglycosides, and fluoroquinolones. This resistance was related to plasmids carrying the blaTEM, blaSHV1, and blaCTXM1 genes. There were significant differences between the resistance proportions of the samples (p value: 0.0000), mainly to penicillin, cefotoxin, and imipenem. Using ERIC-PCR, four clonal states were evidenced that corroborate a degree of genetic differentiation within the isolate set. Antibiotic resistance observed in the isolates is associated with resistance genes present in the bacterial chromosome and plasmids.

Keywords

• antibiotics; escherichia coli; urinary infections; plasmids and resistance.