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 & Objective: The production of plasmid-mediated AmpC beta-lactamases (PMABLs) among urinary Klebsiella pneumoniae isolates causes a severe problem to the successful treatment of urinary tract infections (UTIs). This study was designed to evaluate antimicrobial resistance, the presence of AmpC beta-lactamase genes, and the genetic relatedness among K. pneumoniae strains separated from...

BACKGROUND AND OBJECTIVES Pseudomonas aeruginosa is responsible for devastating nosocomial infections among severely burn patients. Class C of cephalosporinase (AmpC-β-lactamases) is important cause of multiple β-lactam resistance in P. aeruginosa. The aim of this study was to detect the AmpC-β-lactamases producing isolates among carbapenem resistant P. aeruginosa isolated from burn patient. ...

OBJECTIVES To establish the prevalence of the AmpC beta-lactamase phenotype in clinical isolates of Escherichia coli and characterize the genetic resistance mechanisms causing the observed phenotype. METHODS Clinical E. coli (n = 74) with reduced susceptibility to third-generation cephalosporins and resistance to cefoxitin were collected from the Department of Clinical Microbiology at Hvidovr...

In this prospective study all Enterobacteriaceae isolates (n = 2,129) recovered in the clinical microbiology laboratory during October 2009 to April 2010 were analyzed for AmpC production. Clinical and Laboratory Standards Institute (CLSI) cefoxitin and cefotetan susceptibility breakpoints and CLSI critical ESBL diameters were used to screen for potential AmpC producers. In total, 305 isolates ...

BACKGROUND & OBJECTIVES AmpC β-lactamases are clinically significant since these confer resistance to cephalosporins in the oxyimino group, 7-α methoxycephalosporins and are not affected by available β-lactamase inhibitors. In this study we looked for both extended spectrum β-lactamases (ESBL) and AmpC β-lactamases in Klebsiella pneumoniae clinical isolates. METHODS One hundred consecutive, n...

OBJECTIVES The objective of this study was to determine the occurrence of chromosomal and plasmid-mediated β-lactamases (AmpC) genes in a collection of Malaysian isolates of Enterobacter species. Several phenotypic tests for detection of AmpC production of Enterobacter spp. were evaluated and the agreements between tests were determined. METHODS Antimicrobial susceptibility profiles for 117 E...

background  and  objectives: pseudomonas  aeruginosa is responsible for devastating nosocomial infections among severely burn patients. class c of cephalosporinase (ampc-β-lactamases) is important cause of multiple β-lactam resistance in p. aeruginosa . the aim of this study was to detect the ampc-β-lactamases producing isolates among carbapenem resistant p.  aeruginosa isolated from burn patie...

AmpC β-lactamases are cephalosporinases that hydrolyze cephamycins as well as other extended-spectrum cephalosporins and are poorly inhibited by clavulanic acid. Although reported with increasing frequency, the true rate of occurrence of AmpC β-lactamases in different organisms, including members of Enterobacteriaceae, remains unknown. The present study was designed to determine the occurrence ...

BACKGROUND & OBJECTIVES AmpC beta-lactamases are Group I cephalosporinases that confer resistance to a wide variety of beta-lactam drugs. Plasmid mediated AmpC beta-lactamases has been discovered most frequently in isolates of Klebsiella pneumoniae, K. oxytoca, Salmonella, Proteus mirabilis and Escherichia coli. The present study was undertaken to study the occurrence of multidrug resistant and...