Sir, CTX-M enzymes include more than 60 variants belonging to five different clusters (CTX-M-1, CTX-M-2, CTX-M-8, CTX-M-9 and CTX-M-25) according to their amino acid sequence. In recent years, CTX-M enzymes have become the most prevalent extended-spectrum b-lactamases (ESBLs), both in nosocomial and in community settings. Different genetic elements might be involved in the mobilization of blaCT...

OBJECTIVE To investigate the molecular characteristics of extended-spectrum cephalosporin (ESC)-resistant Enterobacteriaceae collected during a cross-sectional study examining the prevalence and risk factors for faecal carriage of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae in humans living in areas with high or low broiler density. METHODS ESC-resistant Enterobacteriace...

We constructed a phylogenetic analysis of class A beta-lactamases and found that the blaCTX-Ms have been mobilized to plasmids approximately 10 times more frequently than other class A beta-lactamases. We also found that the blaCTX-Ms are descended from a common ancestor that was incorporated in ancient times into the chromosome of the ancestor of Kluyvera species through horizontal transfer. C...

OBJECTIVE To investigate CTX-M genotypes among extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC) isolated from patients with community-onset and hospital-onset infections in China, their clonality and the distribution of CTX-M variants in different specimens of community-onset and hospital-onset infections. METHODS ESBL-EC isolates were collected from general hospitals from 2...

OBJECTIVES Several studies on faecal carriage of extended-spectrum β-lactamase (ESBL)/AmpC-producing Escherichia coli have been performed in cattle, but little is known about faecal carriage in veal calves. This study describes the prevalence and molecular characteristics of ESBL/AmpC genes in E. coli isolated from faecal samples of veal calves from 1997 to 2010. METHODS Pooled faecal samples...

2 3 Background: A high rate of resistance to 3 rd generation cephalosporins among Enterobacteriaceae 4 isolates from Egypt has been previously reported. This study aims to characterize the resistance 5 mechanism (s) to extended spectrum cephalosporins among resistant clinical isolates at a medical 6 institute in Cairo, Egypt. 7 Methods: Nonconsecutive Klebsiella pneumoniae (Kp), Enterobacter cl...

This is the first report regarding the detection of blaCTX-M genes encoding CTX-M-1, CTX-M-15, and CTX-M-2 cefotaximases in clinical isolates of enterobacteria collected in hospitals in Bogotá, Colombia. During a period of 4 months in 2005, 117 isolates of enterobacteria having extended spectrum beta-lactamase (ESBL) phenotype were collected from nine third-level hospitals in Bogotá, Colombia. ...

The purpose of this study was to investigate the prevalence of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (ESBL-Ec) in retail chicken meats in Japan. Fifty-six domestic and 50 imported (Brazil, n=36; United States, n=8; Thailand, n=6) chicken meat samples were analyzed. The 162 ESBL-Ec included 111 from 43 (77%) domestic samples and 51 from 26 (52%) Brazilian samples. Fifty...