Two extended-spectrum beta-lactamase (ESBL)-producing salmonella isolates, Salmonella enterica serovar Enteritidis and Salmonella enterica serovar Typhimurium, were analyzed. Both isolates produced the CTX-M-3 ESBL; however, their bla(CTX-M-3) genes were located on different plasmids. The serovar Typhimurium isolate also expressed another ESBL, SHV-2a, and probably the two ESBL genes had been a...

This study was undertaken to investigate drug resistance in Escherichia coli (E. coli) strains isolated from bamboo rats in Zhejiang province of China. One hundred and fifty-four E. coli strains were isolated from dead bamboo rats. Polymerase chain reaction (PCR) was used to detect the representative genes encoding resistance to commonly used β-lactam antibiotics. Highest resistance was observe...

Klebsiella pneumoniae isolates frequently contain complex mixtures of bla(SHV) alleles. A high-resolution melting-based method for interrogating the extended-spectrum activity conferring codon 238 and 240 polymorphisms was developed. This detects minority extended-spectrum beta-lactamase-encoding alleles, allows estimation of allele ratios, and discriminates between single and double mutants.

We investigated a Klebsiella oxytoca isolate demonstrating resistance to imipenem, meropenem, extended-spectrum cephalosporins, and aztreonam. The MICs of both imipenem and meropenem were 32 microg/ml. The beta-lactamase activity against imipenem and meropenem was inhibited in the presence of clavulanic acid. Isoelectric focusing studies demonstrated five beta-lactamases with pIs of 8.2 (SHV-46...

The incidence of extended-spectrum β-lactamases (ESBLs) has been increasing worldwide, but screening criteria for detection of ESBLs are not standardized for AmpC-producing Enterobacteriaceae such as Enterobacter species. In this study, we investigated the prevalence of ESBLs and/or AmpC β-lactamases in Japanese clinical isolates of Enterobacter spp. and the association of plasmid-mediated quin...

BACKGROUND The emergence of carbapenem-resistant Klebsiella pneumoniae poses a serious problem to antibiotic management. We investigated the β-lactamases in a group of carbapenem-resistant K. pneumoniae clinical isolates from Turkey. METHODS Thirty-seven strains of K. pneumoniae isolated from various clinical specimens were analyzed by antimicrobial susceptibility testing, PCR for the detecti...