Molecular Characterization of Clinical Strains of Extended-Spectrum Βeta-Lactamases-Producing Klebsiella Pneumoniae Isolated in A Tertiary Hospital in Dakar-Senegal

Abstract

Klebsiella pneumoniae (K. pneumoniae) isolates are often multidrug-resistant (MDR) and clones producing extended-spectrum beta-lactamases (ESBL) are increasingly reported all over the world. This study aimed to determine drug-susceptibility profiles and characterize ESBL genes in clinical strains of K. pneumoniae in an university teaching hospital of Dakar. Sixty-six ESBL-producing K. pneumoniae strains were selected for this study and subjected to the Kirby-Bauer disk diffusion method and standard polymerase chain reaction (PCR) for the screening of major ESBL genes (bla_CTX-M, bla_CTX-M-9, bla_CTX-M-15, bla_CTX-M-25, bla_OXA-1, bla_TEM, bla_SHV).

All isolates were resistant to ampicillin, ticarcillin, amoxicillin/clavulanic acid combination, cefalotin, cefotaxime, ceftazidime and cefepime, while 60% (40/66) of them were resistant to fosfomycin. Amikacin, ertapenem and imipenem remained effective with respective sensitivity rate of 77.3% (51/66), 75.8% (50/66) and 100% (66/66). bla_CTX-M (64/66; 97%) with its variant bla_CTX-M-15 (63/66; 95.5%) were the most prevalent ESBL genes; followed by bla_TEM (58/66; 87.9%), bla_OXA-1 (47/66; 71.2%) and bla_SHV (31/66; 47%). Sixty-four isolates out of 66 (97%) of isolates carried at least 2 ESBL genes and the most prevalent ESBL gene combinations were (bla_CTX-M-15 + bla_OXA-1 + bla_TEM) (24/66; 36.4%) and (bla_CTX-M-15 + bla_TEM + bla_OXA-1 + bla_SHV) (18/66; 27.3%).

Cephalosporins, quinolones and aminoglycosides (except amikacin) would no l