Environmental microorganisms represent the most relevant reservoir of resistance to antibiotics in the community, and this is due in part to the undue exposure of these organisms to antimicrobial agents. AmpC β-lactamases are clinically important cephalosporinases encoded on the chromosomes of bacteria in the Enterobacteriaceae family and some non-enteric bacteria including Pseudomonas aerugino...

Introduction Extended-spectrum β-lactamases (ESBLs), including the AmpC type, are important mechanisms of resistance among Klebsiella pneumoniae and Escherichia coli isolates. Objective The aim of the study was to investigate the occurrence of AmpC-type β-lactamase producers isolated from two hospitals in Tripoli, Libya. Methods All clinical isolates (76 K. pneumoniae and 75 E. coli) collec...

We investigated the occurrence and genetic basis of AmpC β-lactamase (AmpC)-mediated antibiotic resistance, by examining Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis isolates at a university hospital, from 2007 to 2010. The ampC genes were detected by multiplex AmpC PCR, and AmpC-positive strains were subjected to DNA sequencing. Extended-spectrum β-lactamase (ESBL) production...

AIM To characterize AmpC-beta lactamases among Enterobacteriaceae isolates from clinical samples at Mbarara Regional Referral Hospital. STUDY DESIGN Laboratory-based descriptive cross-sectional study. PLACE AND DURATION OF STUDY Microbiology Department, Mbarara Regional Referral Hospital and MBN clinical Laboratories, between May to September 2013. METHODOLOGY This study included 293 Ente...

b a ckground: quorum-sensing systems regulate expression of several virulence factors in pseudomonas aeruginosa . this study investigated the relation between expression of the las quorum-sensing system and expression of mexy and ampc in35 clinical isolates of p. aeruginosa . m e t hods: antibiotic susceptibility was determined by the disc diffusion method according to the clinical and laborato...

background: extended spectrum β-lactamases (esbls) and ampc β-lactamases enzyme are major sources of resistance to β-lactam antibiotics especially in enterobacteriaceae such as escherichia coli and klebsiella pneumoniae. increasing frequency of the co-existence of esbls with ampc-β-lactamases in bacteria is a serious threat for treating bacterial infections. conclusions: outbreak of isolates co...

Yersinia enterocolitica encodes a chromosomal AmpC β-lactamase under the regulation of the classical ampR-ampC system. To obtain a further understanding to the role of low-molecular-mass penicillin-binding proteins (LMM PBPs) including PBP4, PBP5, PBP6, and PBP7, as well as NagZ and AmpR in ampC regulation of Y. enterocolitica, series of single/multiple mutant strains were systematically constr...

Morganella morganii produces an inducible, chromosomally encoded AmpC beta-lactamase. We describe in this study three new variants of AmpC within this species with apparent pIs of 6.6 (M19 from M. morganii strain PP19), 7.4 (M29 from M. morganii strain PP29), and 7.8 (M37 from M. morganii strain PP37). After gene sequencing, deduced amino acid sequences displayed one to six substitutions when c...

The AmpC β-lactamases are clinically important because they confer resistance to the narrow-, expandedand the broad-spectrum cephalosporins, the β-lactam-β-lactamase inhibitor combinations and aztreonam. The clinical microbiology laboratories should be able to detect the bacterial strains which produce AmpC, since these strains may appear to be susceptible to a particular β-lactam antibiotic in...