Characterization of ESBL-producing Escherichia coli ST131 isolates from Port Elizabeth

This study investigated resistance determinants and genetic relatedness in extended-spectrum beta-lactamase (ESBL) producing Escherichia cob isolates. PCR and DNA sequencing were used for screening isolates for bla(CTX-M), bla(TEM), and bla(SHV) (qnrA, qnrB, qnrC, qnrD, qnrS, aac(6)-1b-cr, and qepA) resistance genes and the sequence type 131 (ST131) clone. Genetic relatedness of E. coli ST131 isolates was determined by pulsed-field gel electrophoresis. Twelve isolates belonged to the ST131 clonal complex, while 8 were positive for aac(6 ')-1b-cr with qnrB1 also detected in 1 isolate. This study describes the first occurrence of CTX-M-9, qnrB1 + aac(6 ')-1b-cr and CTX-M-3 + qnrS1 among E. coli ST131 isolates from South Africa and illustrates their genetic diversity. (C) 2015 Elsevier Inc. All rights reserved.