AmpC beta lactamase producing Gram-negative bacteria have emerged worldwide. It is important to distinguish plasmid mediated AmpC β lactamases from chromosomally mediated enzymes for surveillance, epidemiology and hospital infection control as plasmid mediated genes can spread to other organisms. Occurrence of blaCMY-1 AmpC β-lactamase, a plasmid mediated cephamycinase was studied in 100 consec...

OBJECTIVE To compare the genetic environments of ampC genes in different Acinetobacter baumannii isolates showing different levels of beta-lactam resistance. METHODS The patterns of beta-lactam resistance and beta-lactamase production were investigated for 42 A. baumannii clinical strains. The MICs of various beta-lactams were determined in the presence or absence of the class C cephalosporin...

Background: A prospective study was undertaken to detect metallo-β-lactamases (MBLs) and AmpC β-lactamases in Pseudomonas aeruginosa isolates recovered from patients at Indira Gandhi Medical College, Shimla (H.P). Objective: The study aimed at determining the prevalence of MBL and AmpC producing P. aeruginosa isolates. Material and Methods: A total of 180 isolates were preliminarily screened fo...

Background. Extended-spectrum β-lactamases (ESβLs) and AmpC β-lactamases cause β-lactam resistance in Escherichia coli. Fecal colonization by ESβL- and/or AmpC-positive E. coli is a source of nosocomial infections. Methods. In order to investigate inpatient fecal colonization by ESβLs and AmpC, antibiotic sensitivity tests were conducted and minimum inhibitory concentrations (MICs) were determi...

OBJECTIVES To explore the cause of third-generation cephalosporin resistance in Australian Acinetobacter baumannii isolates belonging to global clone 1 (GC1). METHODS GC1 isolates from Australia were tested for resistance to ceftazidime and cefotaxime using disc diffusion and MICs. PCR was used to determine the context of ISAba1-ampC configurations and amplicons were sequenced. The level of t...

The incidence of resistance by Enterobacteriaceae to β-lactam/β-lactamase inhibitors combination is increasing in Egypt. Three phenotypic techniques, comprising AmpC disk diffusion and inhibition dependent methods using phenylboronic acid (PBA) and cloxacillin, were compared to PCR based method for detection of plasmid mediated AmpC β-lactamase in common urinary tract isolates. A total of 143 i...

To determine whether the widespread clinical use of -lactams has been selective for Citrobacter freundiiderived alleles of plasmid ampC genes, we generated a Bayesian consensus phylogeny of the published ampC sequences and compared the MICs of 16 -lactam antibiotics for Escherichia coli strains containing cloned copies of the C. freundii ampC alleles. We found that for the majority of compounds...

Resistant bacteria have emerged and established themselves worldwide as a threat to the favourable outcome of common infections in community and hospital settings. Beta lactamase production by several gram negative and gram positive organisms is perhaps the most important single mechanism of resistance to penicillins and cephalosporins. ESBL and AmpC beta lactamases are typically associated wit...

Antibiotic resistance is a growing threat. Fifty non repetitive multi drug resistant gram negative bacterial isolates were screened for ESBL, AmpC, ESBL-AmpC co-production using antibiotic tablets. Of these 56% were Escherichia coli, 16% were Klebsiella spp., 39.6% produced ESBLs, 17.2% AmpC and 13.8% showed co-production. Antibiotic tablets sensitivity for ESBL detection was 93.9% compared to ...

Pseudomonas aeruginosa strains that overexpress mexCD-oprJ become hypersusceptible to imipenem. Disruption of AmpC induction has been suggested to cause this phenotype. However, data from this study demonstrate that hypersusceptibility to imipenem can develop without changes in ampC expression or AmpC activity. Furthermore, hypersusceptibility is not caused by changes in expression of the outer...