Detection of Antibiotic Resistance Genes blaSHV, blaTOHO and blaNDM in Pathogenic Gram-Negative Bacilli at the Pietro Annigoni Biomolecular Research Center

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Résumé

Gram-negative bacilli, notably Enterobacteriaceae, are increasingly resistant to antibiotics thanks tothe acquisition and dissemination of extended-spectrum β-lactamases (ESBLs). The present studyaims to identify the blaNDM, blaSHV and blaTOHO genes in clinical strains of Gram-negative bacteria isolated from patients at the Pietro Annigoni Biomolecular Research Center (CERBA),Ouagadougou. The isolation and purification of bacterial strains isolated from the stools and urine ofinternal and external CERBA patients were carried out respectively on selective and Muller Hinton(MH) media. The antibiogram was performed using the disk diffusion method. The API 20E biochemical gallery (BioMérieux, France) was used for the identification of Enterobacteriaceae whilethe blaNDM, blaSHV and blaTOHO genes were detected by conventional PCR. A total of thirty-seven (37) strains of Gram-negative bacilli were included in the present study. The antibiogram showedthat 62.16% (23/37) of them were ESBL producers with 56.52% (13/23) of Escherichia coli; 39.13%(9/23) of Klebsiella sp. and 4.35% (1/23) of Proteus sp. Among them, 60.87% (14/23) of the strainsharbored the bla NDM gene, 56.52% (13/23) bla SHV against 47.83% (11/23) of the strains carrying the blaTOHO gene. The combinations of blaSHV + blaNDM, blaSHV + blaTOHO and blaTOHO + blaNDM genes were found in 30.43% (7/23), 26.08 (6/23) and 17.39% (4 /23) strains, respectively against 8.70% (2/23) of strains carrying blaSHV + blaNDM + blaTOHO. It should also be noted that most of these strains were isolated in urine cultures. This study revealed clinical strains of ESBL-producing Enterobacteriaceae carrying the blaNDM, blaSHV and blaTOHO genes. The simultaneous carriage of two or three genes by certain strains suggests dissemination which requires increased surveillance efforts and the rapid development of new therapeutic solutions.

Mots-clés

ESBL, antibiotic resistance, enterobacteria, blaSHV, blaTOHO, blaNDM