Forty clonally related clinical isolates of Escherichia coli from hospitalized patients were resistant to cefoxitin (MICs, >256 microg/ml) and ceftazidime (MICs, 32 to 256 microg/ml) and were intermediate or resistant to cefotaxime (MICs, 16 to 128 microg/ml) but susceptible to both cefepime (MICs, 0.5 to 2 microg/ml) and imipenem (MICs, 0.125 to 0.25 microg/ml). Resistance to beta-lactams was ...

Introduction: Acinetobacter baumannii is one of the major pathogens causing nosocomial infections due to emergence of resistance to various antimicrobial agents. Resistance due to antimicrobial degrading enzymes is now a worldwide problem and a major reason of concern for the treating physicians. Keeping this in mind, the present study was designed to isolate Acinetobacter baumannii and study v...

Screening of 368 consecutive nonreplicate clinical isolates of Enterobacteriaceae resistant to nalidixic acid and at least one extended-spectrum beta-lactam revealed the presence of qnrA, qnrB, and qnrS determinants, and identified novel qnrB variants, in Citrobacter freundii isolates. This study also revealed, for the first time, the linkage of qnrB, armA, and extended-spectrum and/or AmpC-typ...

The Oxoid combination disk method for detecting extended-spectrum beta-lactamases (ESBLs) depends on comparing the inhibition zones of cefpodoxime (10-microg) and cefpodoxime-plus-clavulanate (10- plus 1-microg) disks. The presence of clavulanate enlarged the zones for all of 180 ESBL-producing klebsiellae by >/=5 mm, whereas zones for cefpodoxime-susceptible isolates and cefpodoxime-resistant ...

Pseudomonas aeruginosa is one of the leading nosocomial pathogens worldwide. Nosocomial infections caused by this organism are often hard to treat because of both the intrinsic resistance of the species (it has constitutive expression of AmpC beta-lactamase and efflux pumps, combined with a low permeability of the outer membrane), and its remarkable ability to acquire further resistance mechani...

OBJECTIVES The aim of this study was to evaluate CHROMagar CTX (CHROMagar France), a novel agar for the selective isolation of Enterobacteriaceae expressing the bla(CTX-M) gene in the presence of enteric bacteria expressing AmpC enzymes. METHODS A panel of 150 Gram-negative bacteria (mainly Escherichia coli, Enterobacter, Klebsiella, Pseudomonas and Salmonella) isolated from humans and animal...

Two mechanisms account for AmpC activity in Escherichia coli, namely, mutations in the ampC promoter and attenuator regions resulting in ampC overexpression and acquisition of plasmid-carried ampC genes. In this study, we analyzed 51 clinical E. coli isolates with reduced susceptibility to amoxicillin-clavulanic acid, piperacillin-tazobactam, or extended-spectrum cephalosporins for the presence...

background: ampc and esbls as mediated-plasmid extended spectrum β-lactabases are the main factors of resistance to extended-spectrum cephalosporins in enterobacteriacea especially e. coli and will follow treatment failure, high costs of treatment in human and economic losses in the poultry industry. objectives: the purpose of this study was to screen and study the faecal e. coli isolates produ...

Genes encoding the CMY-2, CTX-M-14, and SHV-12 beta-lactamases were detected in three of five Escherichia coli isolates from fecal samples from healthy chickens which showed resistance or diminished susceptibility to extended-spectrum cephalosporins. A -42 mutation at the promoter region of the ampC gene was detected in the other two isolates.

Serratia marcescens strain AH0650_Sm1 is a clinical multidrug-resistant isolate from Australia. Here, we report its annotated draft genome comprising 20 contigs. We identified chromosomal antimicrobial resistance genes including a tet(41) variant, an aac(6')-Ic variant, ampC, a metallo-beta-lactamase, and several putative multidrug efflux pumps, as well as a novel prophage.