Characteristics of infections caused by extended-spectrum β-lactamase–producing Escherichia coli from community hospitals in South Africa

A study was designed to characterize 22 nonrepeat extended-spectrum β-lactamase (ESBL)–producing Escherichia coli clinical isolates recovered from specimens originating from doctor's consultation rooms and several private and a state hospital in the Cape Town metropolitan area during 2008–2009. Characterization was done by using isoelectric focusing, PCR, sequencing of blaCTX-M, blaTEM, blaSHV, and blaOXA as well as PCR for plasmid-mediated quinolone resistance determinants, ST131, phylogenetic groups, and plasmid replicon typing. Genetic relatedness was determined with pulsed-field gel electrophoresis using XbaI and multilocus sequencing typing. The majority of patients (17/22 [77%]) presented with urinary tract infections (UTIs) originating from the hospital setting. Thirteen (59%) of the isolates produced CTX-M-15, 7 produced CTX-M-14, and 1 isolate each produced CTX-M-3 and SHV-2, respectively. Sixteen (73%) isolates were nonsusceptible to ciprofloxacin and 8 (36%) were positive for aac(6′)-Ib-cr. Overall, 10/22 (45%) of ESBL producers belonged to clonal complex ST131 that produced CTX-M-15 or CTX-M-14. Molecular characteristics of ST131 showed that this clone belonged to phylogenetic group B2. Our study illustrated that clonal complex ST131 isolates producing CTX-M-15 and CTX-M-14 had emerged as an important cause of UTIs due to ESBL-producing E. coli in the Cape Town area. This is the first report to identify ST131 in ESBL-producing E. coli from Southern Africa.