Diversity of bla-type genes in extended-spectrum β-lactamase-producing Klebsiella pneumoniae isolated during 2003 — 2004 at Pretoria Academic Hospital

Abstract

Multidrug resistance is emerging in many Gram-negative bacteria like Klebsiella pneumoniae, an important cause of nosocomial infections. Increasing production of extended-spectrum beta-lactamases (ESBLs) in this species has become a growing concern, due to associations with longer duration of hospital stay and greater healthcare costs. A few studies have investigated ESBL production in bacterial isolates collected in Africa but only one included K. pnenmoniae. The aim of this study was to determine the prevalence of the ß-lactamases TEM, SHV and CTX-M detected in K. pneumoniae isolated from patients with nosocomial infections at Pretoria Academic Hospital. Fifty K. pneumoniae isolates obtained from blood cultures reported to be resistant to one or more oxyimino-cephalosporins were examined Detection of sequences coding for bla_TEM'bla_SHVand bla_CTX-M were performed wuth genomic DNA extracted from all isolates. Polymerase chain reaction (PCR) amplification of target DNA was performed and the resulting gel-electrophoresis patterns examined TEM-and SHV-type ß-lactamases represented 10 and 18%, respectively, in isolates analysed. Isolates that tested negative for both TEM- and SHV-type ß-lactamases comprised 6% of the study population. None of the 50 isolates examined, were positive for bla_CTXM•