Molecular Characterization of blaCTX-M-15 Gene Among blaTEM and blaSHV Variants Isolated on Gram Negative Bacilli Collected in Emergency Units at University Hospital Center, Yalgado Ouedraogo, Burkina Faso

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Résumé

Extended-spectrum β-lactamase producing Gram negative bacilli constitute a global public health threat. The ESBLs CTX-M, TEM and SHV remain the most frequently isolated worldwide, with high proportions of CTXM reported and widely distributed in pathogens. Several authors report that the bacterial strains harboring the CTX-M-15 gene are generally multidrug-resistant strains. This study aim to identify the variants of blaCTX-M, blaTEM and blaSHV hosted by Gram negative bacilli at hospital center Yalagdo Ouédraogo. This study take on bacterial strains collected in a previous study (DOI: 10.5897/AJB2014.13908). Bacterial strains had been isolated from biological samples such as stools, urine, blood, cerebrospinal fluid, effusion fluids (pus, ascitic fluid, pleural fluid...) and genital swabs.. During this previous study, 259 strains resistant to at least one thirdgeneration cephalosporin had been collected and identified using API20E. This study had shown that some of these bacterial strains harbor blaCTX-M, blaTEM and blaSHV. For the present study, from a young bacterial culture, genomic DNA extraction was performed by the boiling method and conventional PCR was used to confirm the presence of resistance genes. PCR products from a total of 17 bacterial strains were subjected to Sanger sequencing for genes variants determination. In the previous study, among 259 strains collected, molecular characterization had shown that 112 strains (65.49%) were positive for blaCTX-M screening; 44 strains (25.73%) for blaTEM screening and 32 strains (18.71%) for blaSHV. For the present study, among 17 bacterial strain consisting to 7 Escherichia coli, 4 Klebsiella pneumoniae, 3 Pseudomonas aeruginosa, 1 Enterobacter sp, 1 Citrobacter sp and 1 Salmonella tiphy, blaCTX-M-15 and blaSHV-28 genes were found respectively on 82.35% and 5.88% of all bacterial strains analyzed, while the blaTEM-1 and blaSHV-11 were each harbored by 23.53% of the isolates. The current situation of bacterial resistance remains dominated by the spread of broad-spectrum betalactamases. A high proportion of bacterial strains studied resist by production of ESBLs type CTX-M-15. Measures must be implemented to slow the emergence and spread of ESBL-producing Gram-negative bacilli through the appropriate use of antibiotics.

Mots-clés

Gram negative bacilli, PCR, sequencing, blaTEM, blaSHV, blaCTX-M-15