Molecular Characterization of blaCTX-M-G1 and blaOXA Genes in Enteropathogenic Escherichia Coli Isolated from Children under Two Years in Ouagadougou, Burkina Faso

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Résumé

Abstract: Extended Spectrum β-lactamases (ESBLs) are evolved forms of β-lactamases produced mainly by gram-negative bacilli that allow them to inactivate penicillins, cephalosporins and Aztreonam. They are encoded by various genes that are either chromosomal or plasmid and hosted by bacterial strains especially those of E. coli widely distributed in the world. The presence of antibiotic resistance genes increases the pathogenicity of bacterial strains already equipped with virulence factors.

Objectives: The aim of this study was to characterize the CTX-M-G1 and OXA genes in enterophatogenic Escherichia coli Extended-Spectrum β-Lactamases-producing strains isolated from children under two years of age at Protestant Hospital Center Schiphra in Ouagadougou.

Methods: A total of 53 strains of Escherichia coli responsible for human infections and isolated from stool were subjected to serotyping and susceptibility tests targeting antibiotics such as ceftriaxone, cefotaxime, ceftazidime, imipenem were performed according to discs diffusion method on Mueller-Hinton agar. The search for resistance genes was carried out by classical PCR.

Results: Among 53 strains analyzed, 26.41% represented enteropathogenic Escherichia coli. The susceptibility test showed high proportions of resistance to third-generation cephalosporins, 27.27% (ceftriaxone), 75% (ceftazidime) and 100% (cefotaxime). Imipenem was the most active of all the strains tested with a sensitivity ratio of 100%. Analysis of PCR products after agarose gel electrophoresis revealed 32 strains (60.37%) harboring at least one of the resistance genes sought. Of these strains, 28.30% harbored the blaOXA gene, 32.07% the blaCTX-M-G1 gene. The co-existence of blaOXA and blaCTX-M-G1 genes was found on 18.86%.

Conclusion: This study calls attention to community and hospital hygiene measures and the need for monitoring to limit the spread of virulent, antibiotic-resistant strains.

Keywords: Enteropathogenic Escherichia coli, blaCTX-M, blaOXA, infants, two years

Mots-clés

Enteropathogenic Escherichia coli; blaCTX-M; blaOXA; infants; two years