Antimicrobial resistance in extended spectrum -lactamases (ESBL)-producing Escherichia coli isolated from human urinary tract infections in Ndjamena, Chad

摘要

The prevalence of antibiotic resistance among extended-spectrum β-lactamase (ESBL)-producing Escherichia coli has increased markedly in recent years. The purpose of this work was to investigate the occurrence and the antibiotic susceptibility of ESBL-producing E. coli in the urinary tract of the patients in Chad. Clinical strains of E. coli were isolated onto CLED agar and tested for ESBL production by using the double disk synergy test. Susceptibility to antibiotics was tested according to the guidelines of Clinical Laboratory Standards institute. Out of 283 cultures tested, 57 (20.14%) were positives for urinary tract infections of which 31 (54.5%) were identified as E. coli resistant to third generation cephalosporins. All these E. coli isolates expressed various level of resistance to antibiotics tested. Among these strains, 77.41 were detected to be ESBL-producers and 22.58% were non-producers. Moreover, resistance to the third generation cephalosporins was associated with significant cross resistance of 62, 38, 79, 70 and 95% to gentamicin, amikacin, nalidixic acid, ciprofloxacin and trimethoprim-sulfamethoxazole, respectively. However, cefoxitin and imipenem were found to still be efficient against the ESBL producers. These findings indicate that the trend was towards increased spread of ESBL-producing E. coli that could restrict the choice of antibiotic for the treatment of urinary tract infections in Chad.