Faecal carriage of extended-spectrum β-lactamase-producing Escherichia coli and Klebsiella spp. in Mozambican students.

Abstract

In recent years, the world has seen a surge in extended-spectrum β-lactamase (ESBL)-producing bacteria. Among antibiotic resistance mechanisms, the production of β-lactamase is the most rapidly developing and clinically significant in Gram-negative bacteria. In the present study, a total of 275 stool samples were collected from students of both sexes in three student residencies of Eduardo Mondlane UniversityMozambique from January to February 2016. All samples were cultured on MacConkey agar with ceftriaxone (1mg/L) and without ceftriaxone. The isolates were biochemically identified with API20E test. Confirmed E. coli and Klebsiella spp. isolates were subjected to antimicrobial susceptibility testing by the disc diffusion method and ESBL strains were confirmed with the disc approximation method. From these samples, 56 ESBL positive E. coli(n=35) and Klebsiella spp. (n=21) strains were isolated. Among the ESBL-positive isolates, 39.3% (22/56) were cefoxitin resistant and none were confirmed as carbapenemase producers. The frequency of ESBL colonization in both sex were similar for E. coli and Klebsiella spp. Among the ESBL-positive isolates, 50% (28/56) of the isolates only contained class A ESBLs, 5.4% (3/56) only class C ESBLs, and 44.6% (25/56) both class A and C ESBLs. Among the E. coli strains, 100% were resistance to ampicillin, and both E. coli and Klebsiella spp. demonstrated69.6% resistance to tetracycline and cotrimoxazole, 62.5% to ceftazidime, 33.9% to ciprofloxacin, and 34.8% to cefoxitin. None of the isolates showed resistance to meropenem. In total, 78.6 % of ESBL strains were defined as multi-resistant. The ERIC-PCR demonstrated low similarity among the strains. This study demonstrated that the carriage rates and the diversity of ESBL genes among the students are high.