Emergence of Carbapenem-resistant Enterobacteriaceae among Extended-spectrum Beta-lactamase Producers in Accra, Ghana

Abstract

Previous studies in Accra had established that extended-spectrum beta-lactamase (ESBL) producers were increasingly becoming a public health nuisance. Since ESBL producers resulted in multi-drug resistance among most beta-lactams and non-beta-lactams, the antibiotic of choice for the treatment of these ESBL infections was carbapenems such as imipenem, meropenem and ertapenems. Hence the emergence and spread of carbapenem resistant bacteria may lead to therapeutically dead end for life-threatening infections. This study therefore focussed on the occurrence of carbapenem resistant Enterobacteriaceae among ESBL producers from clinical specimens analysed at MDS-Lancet Laboratories, Accra, Ghana. One thousand (1000) clinical isolates were identified and analysed for ESBL producers using the combined disk synergy method. In order to determine the carbapenemase producing ESBL bacteria and the antibiotic of choice for treating carbapenem resistant infections, antimicrobial susceptibility testing was performed to determine the minimum inhibition concentration of the antibiotics used against the ESBL producers. The antibiotics used included imipenem, meropenem ertapenem and other antibiotics. The results indicated that 600 (75%) of the clinical isolates were ESBL producers. Among the 600 ESBL producers, 43 (7.2) were carbapenem resistant bacteria including 7 different Gram negative bacterial species. Among the carbapenemase producers, Escherichia coli (34.9%) and Klebsiella pneumoniae (25.6%) were the dominant bacterial species. The carbapenem resistant bacteria indicated multi-drug resistance to penicillins (100%), cephalosporins (100%), amoxicillin-clavulanic acid (100%), piperacillin-tazobactam (100%), ciprofloxacin (83.7%), gentamycin (79.7%), amikacin (27.9%), colistin (18.6%) and fosfomycin (11.6%).  Colistin seems to be is the drug of choice for treating carbapenem resistant strains. Although fosfomycin showed a higher activity, it is only recommended for urinary tract infections. Evidence based antibiotic usage and nosocomial infection control will help to control the emergence of carbapenem resistant strains in Accra, Ghana. Also, there is the need to intensify research in the use of natural products to treat resistant bacterial infections.

Keywords: Carbapenem, ESBLs, Antibiotics, Colistin