A variety of CTX-M-type extended-spectrum β-lactamases (ESBLs), including hybrid ones, have been reported in China that are uncommon elsewhere. To better characterize the substrate profiles and enzymatic mechanisms of these enzymes, we performed comparative kinetic analyses of both parental and hybrid CTX-M enzymes, including CTX-M-15, -132, -123, -64, -14 and -55, that are known to confer vari...

CTX-M-producing Escherichia coli isolates from three Croatian hospitals were analyzed. All bla(CTX-M-15) genes and one bla(CTX-M-3a) gene resided in widely spread ISEcp1 transposition modules, but other bla(CTX-M-3a) genes were in a new configuration with two IS26 copies, indicating a new event of gene mobilization from a Kluyvera ascorbata genome. The study confirmed the role of the E. coli ST...

OBJECTIVES To characterize a novel CTX-M chimera, CTX-M-137, from Escherichia coli clinical isolates in China. METHODS Isolates were collected from five hospitals between 22 February 2009 and 20 December 2011. Resistance genes were investigated by PCR. blaCTX-M-137 was cloned and purified for kinetic measurements. Conjugation experiments, S1-PFGE and Southern blotting were performed to study ...

Among 603 isolates of Enterobacteriaceae collected between June and November 2003 from three university hospitals within Korea, bla(CTX-M-3), bla(CTX-M-15), bla(CTX-M-14), and bla(CTX-M-9) were detected in 41 isolates of species from five different genera of Enterobacteriaceae, Escherichia coli, Klebsiella pneumoniae, Citrobacter freundii, Enterobacter spp., and Serratia marcescens.

A combination of phenotypic and genotypic methods was used to investigate 70 unique Escherichia coli clinical isolates identified as producing extended-spectrum beta-lactamases (ESBLs) at a medical center in Pittsburgh, PA, between 2007 and 2008. Fifty-seven isolates (81%) produced CTX-M-type ESBLs, among which CTX-M-15 was predominant (n = 46). Isolates producing CTX-M-2, -9, -14, and -65 were...

results of the 100 klebsiella isolates, 41 (41%) demonstrated resistance or reduced susceptibility to ceftazidime and/or aztreonam and 35% (n = 35) were esbl-producers. twenty-eight (8o%) of the esbl-producing isolates carried the blactx-m type genes. based on pcr assays and sequencing of blactx-m genes, ctx-m-1, ctx-m-2 and ctx-m-9 were identified in 21 (60%), 15 (42%) and nine (34%) of these ...

OBJECTIVE To investigate the local epidemiology of Klebsiella penumoniae carrying bla(CTX-M-15) in southern China and to characterize the genetic environment of bla(CTX-M-15). METHODS PCR and DNA sequencing were used to detect and characterize the genetic contexts of bla(CTX-M-15). The clonal relatedness of isolates carrying bla(CTX-M-15) was determined by pulse-field gel electrophoresis. Con...

We determined the complete nucleotide sequences of three plasmids that encode CTX-M extended-spectrum beta-lactamases (ESBLs) in pulsed-field gel electrophoresis-defined United Kingdom variants (strains A, C, and D) of the internationally prevalent Escherichia coli O25:H4-ST131 clone. Plasmid pEK499 (strain A; 117,536 bp) was a fusion of type FII and FIA replicons and harbored the following 10 ...