High levels of extended-spectrum beta-lactamases in a major teaching hospital in Ghana: the need for regular monitoring and evaluation of antibiotic resistance

Favored by their comparatively high effectiveness, low toxicity, and low cost, beta-lactams are prescribed more often than any other antibiotic.1,2 Heavy use of this antibiotic has resulted in selection of drug-resistant bacteria caused by the production of beta-lactamases, and is now an increasing problem, especially in Enterobacteriaceae. Extended-spectrum beta-lactamase (ESBL)–producing Enterobacteriaceae are resistant to penicillins, narrow-spectrum and extended-spectrum cephalosporins, except the cephamycins, and aztreonam.3–5

Most importantly, in a large prospective study of consecutive patients with bacteremia, treatment failure was observed although the strains were susceptible in vitro to the antibiotics used. This failure of beta-lactam antibiotics was attributed to inoculum effect, under-dosing, and failure to achieve pharmacodynamic targets.4,6 Despite these public health concerns, few studies have reported on the problem of ESBLs in Africa in general and Ghana in particular. In Africa, outbreaks of infection with ESBL-producing enterobacteria have been reported in South Africa,7–9 Egypt,10,11 Tunisia,12 Morocco,13 Tanzania,14 and Nigeria.15 In Ghana, routine ESBL detection is absent. Moreover, no systematic survey of ESBL-producing bacteria has been conducted, and the extent of the ESBL problem remains unclear.

To investigate the extent of the ESBL problem, we examined clinical isolates of Enterobacteriaceae collected at Korle-Bu Teaching Hospital (KBTH) in Accra, Ghana. The aim of this study was to determine the occurrence of ESBLs in the hospital and report on the resistance of ESBL-producing and non-producing strains to potentially useful antimicrobial agents.