Detection of Antibiotic Resistance Genes bla SHV, bla TOHO and bla NDM in Pathogenic Gram-Negative Bacilli at the Pietro Annigoni Biomolecular Research Center

Abstract

Gram-negative bacilli, notably Enterobacteriaceae, are increasingly resistant to antibiotics thanks to the acquisition and dissemination of extended-spectrum β-lactamases (ESBLs). The present study aims to identify the bla NDM, bla SHV and bla TOHO 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 of internal 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 while the bla NDM, bla SHV and bla TOHO 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 showed that 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 strains harbored the bla NDM gene, 56.52% (13/23) bla SHV against 47.83% (11/23) of the strains carrying the bla TOHO gene. The combinations of bla SHV + bla NDM, bla SHV + bla TOHO and bla TOHO + bla NDM 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 bla SHV + bla NDM + bla TOHO. 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 bla NDM, bla SHV and bla TOHO 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.