OBJECTIVES AmpC β-lactamases are classified as Amber Class C and Bush Group 1. AmpC β-lactamases can hydrolyze broad and extended-spectrum cephalosporins, and are not inhibited by β-lactamase inhibitors such as clavulanic acid. This study was conducted to identify DHA-23, a novel plasmid-mediated and inducible AmpC β-lactamase obtained from Enterobacteriaceae. METHODS A total of 210 carbapene...

conclusions this study showed that multiple β-lactamases can be produced in burn isolates. this suggests that use of cephalosporins and carbapenems should be restricted in burn isolates to minimize the development and spread of these multidrug resistant pathogens. results there was 99% resistance to carbenicillin, and ticarcillin, 98% to cotrimoxazole, 96% to ciprofloxacin, and aztreonam, 95% t...

CFE-1 is a unique plasmid-encoded AmpC β-lactamase with the regulator gene ampR. It imparts high resistance to most cephalosporins with constitutive high-level β-lactamase activity. Here, the β-lactamase activities and expression levels of ampC with or without ampR were investigated. Results suggested that the resistance of CFE-1 to cephalosporins is caused by a substitution in AmpR, in which t...

Background & objectives: Members of the family enterobacteriaceae comprise the most common gram-negative isolates in microbiology laboratories. Amongst these members, multiple antibiotic-resistant isolates including those producing extended spectrum β-lactamases (ESBL) and AmpC β-lactamases (AmpC) have increased steadily. Further, metallo-β-lactamase (MBL) producing strains are also recently de...

The increasing incidence of inducible chromosomal AmpC β-lactamases within the clinic is a growing concern because these enzymes deactivate a broad range of even the most recently developed β-lactam antibiotics. As a result, new strategies are needed to block the action of this antibiotic resistance enzyme. Presented here is a strategy to combat the action of inducible AmpC by inhibiting the β-...

results fifty isolates were positive on the screening test. among them, positive pcr reactions were identified in 35/221 and 12/77 isolates of e. coli and klebsiella spp., respectively, including 16 (34.0%) for cit only, 7 (14.8%) for dha only, and 24 (51.0%) for both dha and cit. no isolate was positive for fox or mox. no proteus organism was positive for ampc genes. conclusions currently, phe...

PURPOSE Salmonella spp. are important foodborne pathogens exhibiting increasing resistance to antimicrobial drugs. Resistance to broad-spectrum β-lactams, mediated by extended-spectrum β-lactamase (ESBL) and AmpC β-lactamase enzymes is fast spreading and has had negative impacts on the clinical outcomes, particularly on third-generation cephalosporins. This study investigated the carriage of Am...

The aim of the present study was to investigate the resistance of plasmid-mediated AmpC β-lactamase in Pseudomonas aeruginosa, to detect and identify the AmpC genotype and to provide evidence for antibiotic applications in the clinic. Resistance phenotype in 108 strains of clinically isolated P. aeruginosa was determined by Kirby-Bauer disk test and cefoxitin three dimensional test in AmpC-posi...

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...