prevalence of extended spectrum β-lactamase, ampc β-lactamase and metallo-β-lactamase among gram negative bacilli recovered from clinical specimens in benin city, nigeria

Background: multidrug resistant bacteria continue to be a bane in the treatment of clinical infections in nigeria. knowledge of trends in resistance mechanisms is vital in determining available therapeutic options. objective: this study was aimed at determining the prevalence, distribution and antimicrobial susceptibility of extended spectrum β-lactamase (esbl), ampc β-lactamase and metallo-β-lactamase (mbl)-producing gram negative bacteria (gnb) recovered from clinical specimens in a tertiary hospital in southern nigeria. materials and methods: a total of 309 consecutive non-repetitive clinical bacterial isolates were recovered from various clinical specimens. the presence of esbl, ampc β-lactamase and mbl as well as the susceptibility profiles were determined using standard microbiological techniques. results: esbl was the most prevalent (p < 0.0001) of the 3 enzymes detected in this study. bacterial isolates recovered from inpatients had a higher likelihood of producing esbl than those recovered from out-patients (odds ratio [or] = 2.225, 95% ci = 1.375, 3.599; p = 0.0015). the highest prevalence of esbl, ampc and mbl enzyme was observed for providencia species, pseudomonas aeruginosa and citrobacter species respectively. β-lactamase positive isolates showed poor activity against cephalosporin, amoxicillin-clavulanate, gentamicin and the fluoroquinolones. isolates that produced any of the three β-lactamase enzymes showed more resistance to antibacterial drugs than β-lactamase negative bacterial isolates. conclusion: a prevalence of 41.7%, 15.2% and 28.5% was observed for esbl, ampc β-lactamase and mbl respectively in this study. isolates that produced any of the enzymes were more resistant to antibacterial agents. prudence in antibiotic use is strongly advocated.