Comparative Analysis of Antimicrobial Resistance of Extended-Spectrum Beta-Lactamase Producers and Non-Extended-Spectrum Beta-Lactamase Producers among Bacterial Isolates in Accra, Ghana

Abstract

Antibiotic resistance may occur naturally but misuse of antibiotics in humans and animals is accelerating the process. One of the modes of resistant mechanism is the production of extended-spectrum beta-lactamases (ESBLs) by the bacteria. ESBLs are plasmid-mediated beta-lactamases that are capable of hydrolysing penicillins, cephalosporin and several non-beta-lactam antibiotics. This laboratory-based study sought to compare the rate of antimicrobial resistance between ESBL and non-ESBL-producers in Accra. Four hundred K. pneumoniae and E. coli isolates were collected at the Korle Bu Teaching Hospital and screened for ESBL and non-ESBL-producers using the combined disk method and Vitek 2 system. The minimal inhibition concentrations (MICs) for 17 commonly used antibiotics were determined using Vitek 2 System. The results indicated significant difference (P<0.05) between the antimicrobial resistance of ESBL-producers and non-ESBL producers except for amikacin and imipenem. The 198 non-ESBL phenotypes recorded relatively low antimicrobial resistance to cefotaxime 4(2%), ceftazidime 4(2%), nitrofurantoin 6(3%), amoxicillin/clavulanic acid 27(13.6%), gentamicin 34(17.2%) and ciprofloxacin 78(39.4%). In contrast, the 202 ESBL producers registered high antibiotic resistance to cefotaxime 197(97.5%), ceftazidime 175(86.6%), nitrofurantoin 94(46.5%), amoxicillin/clavulanic acid 64(31.7%), gentamicin 166(82.2%) and ciprofloxacin 161(79.7%). Cephalosporins and nitrofurantoin are suitable for the treatment of non-ESBL producers while imipenem and amikacin is the drug of choice for treating ESBL-producing infections. Evidence based antibiotic usage will help to control the spread of resistance by ESBL producers in Accra, Ghana. Also, there is the need to intensify research in the use of natural products to treat ESBL infections.

Keywords: Extended spectrum beta-lactamase, Resistance, Bacteria, Antibiotics