background: ampc type β-lactamases are commonly isolated from extended-spectrum cephalosporin-resistant gram-negative bacteria. also, resistance appeared in bacterial species not naturally producing ampc enzymes. therefore, a standard test for the detection of the plasmid-mediated ampc enzyme and new breakpoints for extended spectrum cephalosporins are urgently necessary. objectives: to detect ...

background: in order to select a better antibiotic choice for treatment of pseudomonas aeruginosa infections, this study was conducted to determine the frequency of resistance to some antipseudomonal β-lactams in p. aeruginosa isolates from patients in tehran, iran. in addition, the relation between presence of genes known to be responsible for resistance to β-lactams (ampc, mexc1,2,and mexc3,4...

Background: In order to select a better antibiotic choice for treatment of Pseudomonas aeruginosa infections, this study was conducted to determine the frequency of resistance to some antipseudomonal β-lactams in P. aeruginosa isolates from patients in Tehran, Iran. In addition, the relation between presence of genes known to be responsible for resist...

conclusions a high prevalence of multiple β-lactamase production was observed among the ampc producers (60%), of which the majority co-produced ampc and mbl. the current study results showed correlation between β-lactamase production and the presence of antibiotic resistance genes in the isolates. results all isolates were multidrug resistant. ampc, esbl and mbl production were observed in 35 (...

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...

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...

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...

Therapeutic options for infections caused by gram-negative organisms expressing plasmid-mediated AmpC beta-lactamases are limited because these organisms are usually resistant to all the beta-lactam antibiotics, except for cefepime, cefpirome, and the carbapenems. These organisms are a major concern in nosocomial infections and should therefore be monitored in surveillance studies. Six families...

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...

As a part of a nationwide study in Spain, 15 clinical isolates of Acinetobacter genomic species 3 (AG3) were analyzed. The main objective of the study was to characterize the ampC genes from these isolates and to determine their involvement in beta-lactam resistance in AG3. The 15 AG3 isolates showed different profiles of resistance to ampicillin (range of MICs, 12 to >256 microg/ml). Nucleotid...