Antibiotic susceptibility of uropathogenic <i>Escherichia coli</i> isolates in a hospital setting in Ouagadougou, Burkina Faso: A twelve-year retrospective analysis

Abstract

Background: Escherichia coli is the main bacterium responsible for uncomplicated urinary tract infections (UTI). The increasing frequency of antibiotic  resistance in E. coli isolates from UTI poses concern in their therapeutic management. The aim of this study is to describe the current antibiotic resistance  profile of E. coli clinical isolates at the Yalgado Ouedraogo University Hospital of Ouagadougou (CHUYO), Burkina Faso, with a view to revising  the treatment protocols for bacterial UTI.

Methodology: This was a retrospective review and descriptive study of all E. coli isolates from febrile UTI at CHUYO from January 2010 to December 2021.  During this period, two techniques were used to perform antibiotic susceptibility test; agar diffusion from 2010 to 2018 and commercial liquid  susceptibility testing from 2019 to 2021 using the BD Phoenix M50 automated system. The detection of ESBLs was performed using the Expert System of  the automated system or a synergy test combining an amoxicillin-clavulanic acid and a 3 rd generation cephalosporin (3GC) disc.

Results: A total of 2055 non-repetitive strains of E. coli were isolated from UTI over the period of study, with 62.0% (1274) of isolates resistant to 3GC.  Resistance to 3GC by ESBL production was the most dominant mechanism in 83.1% of cases (1059/1274). Among the 781 (38.0%) 3GC-susceptible  isolates, there were high resistance rates to ampicillin (75.2%) and cotrimoxazole (60.2%), but these isolates retained full susceptibility to imipenem  (carbapenem) and fosfomycin. As for the 3GC-resistant strains, there was high resistance to cotrimoxazole (93.0%) and ciprofloxacin (90.3%) but relatively  low to medium resistance to gentamicin (56.0%) and amikacin (26.3%), and low resistance to nitrofurantoin (10.0%), fosfomycin (6.1%) and imipenem  (4.2%). About one third (31.7%) of all the isolates tested were resistant to both ceftriaxone and gentamicin.

Conclusion: In view of the results, the  implementation of rapid diagnostic tools such as the β-lactamase test to guide empirical antibiotic therapy is essential for an early and efficient  management of febrile UTI at the local level in Burkina Faso.