Antibiotic resistance in uropathogenic Escherichia coli strains at Brazzaville University Hospital, Congo and the therapeutic consequences Résistance aux antibiotiques des souches uropathogènes d'Escherichia coli au CHU de Brazzaville, Congo et conséquences thérapeutiques

Abstract

Background: Urinary tract infections (UTIs) are a very frequent reason for consultations and antibiotic prescriptions in everyday practice. Excessive and inappropriate use of antibiotics is responsible for the emergence and spread of multidrug-resistant (MDR) uropathogenic bacteria. The aim of this study was to determine the frequency of isolation and antibiotic resistance of uropathogenic strains of Escherichia coli (UPEC) isolated in the bacteriology-virology laboratory of the University Hospital Centre (CHU) in Brazzaville, Congo.
Methodology: This was a descriptive retrospective study over a 6-month period (from 1 April to 31 September 2022) that included all non-redundant uropathogenic UPEC strains isolated from urine samples of patients with UTIs referred to the bacteriology-virology laboratory of the University Hospital of Brazzaville, Congo. The strains were isolated from urine samples after inoculation onto Cystine Lactose Electrolyte Deficient agar (CLED), and incubating aerobically at 37°C for 24 hours. Identification was carried out using BioMérieux API 20 E galleries and antibiotic susceptibility testing was performed on Mueller Hinton agar medium using selected antibiotic discs. Extended spectrum β-lactamase (ESBL) production by the isolates was confirmed by double disc synergy test.
Data were analysed using Microsoft Office Excel 2013.
Results: Of the 187 non-repetitive uropathogenic Enterobacteriaceae isolated from urine samples of 187 patients with clinical UTIs, 81 were strains of UPEC, giving an overall frequency of UPEC isolation of 43.0%. The modal age of patients from whom UPEC strains were isolated was 57 years (age range 2 to 86 years), with 49 from females and 32 from males (F: M ratio of 1.5). The UPEC strains showed high rates of resistance to amoxicillin (94.0%), amoxicillin-clavulanic acid (84.0%), piperacillin-tazobactam (73.0%), ceftriaxone (52.0%), cefixime (54.0%), cefotaxime (55.0%), ceftazidime (58.0%), gentamicin (42.0%), ciprofloxacin (55.0%) and sulfamethoxazole-trimethoprim (90.0%) but relatively low resistance rates were observed with imipenem (4.0%), fosfomycin (8.0%) and amikacin (18.0%). The ESBL-producing strains accounted for 24.5% (46/187) of all uropathogenic Enterobacteriaceae isolates, and compared to the non-ESBL producing strains, had significantly higher resistance rates to gentamicin (p=0.018), ciprofloxacin (p=0.0003), ceftazidime (p<0.0001), ceftriaxone (p<0.0001), cefixime (p<0.0001), cefotaxime (p<0.0001), piperacillin-tazobactam (p=0.0006), and amoxicillin-clavulanate (p=0.0024).
Conclusion: Our results show high rates of in vitro resistance of UPEC strains to commonly used antibiotics, which potentially limits therapeutic options and therefore a real public health challenge in Congo.