abstract        background and objectives: pseudomonas aeruginosa is the most frequent opportunistic pathogen isolated from the sputum of patients with cystic fibrosis (cf). resistance to β -lactam antibiotics may arise from over expression of the naturally occurring ampc cephalosporinases or acquired extended-spectrum β-lactamases (esbl). the aim of this study was to determine the antibiotic r...

Escherichia coli (E. coli) is a common opportunistic pathogen for nosocomial infection. The aim of the study was to examine the phenotype, genotype and epidemiology of plasmid-mediated AmpC β-lactamases in E. coli. In total, 96 clinical isolates of repeated E. coli were collected from different hospitals between August and October 2012. Using a cefoxitin disk diffusion method to identify the ph...

BACKGROUND & OBJECTIVES Plasmid mediated AmpC β-lactamase (PMABL) resistance in Escherichia coli and Klebsiella spp. is an emerging problem worldwide. Phenotypic methods are commonly used for detection of PMABL production in Gram-negative isolates, but molecular data about the prevalence of plasmid-mediated AmpC-type resistance at the national level are needed. Hence, a prospective study was un...

OBJECTIVES To determine the distribution of acquired AmpC beta-lactamases in 173 isolates of Escherichia coli and Klebsiella spp. submitted to the UK's national reference laboratory for antibiotic resistance. METHODS MICs were determined and interpreted according to BSAC guidelines. Candidate isolates were those resistant to cefotaxime and/or ceftazidime, irrespective of addition of clavulani...

Pseudomonas aeruginosa is one of the most important causes of nosocomial infection and it has increasing resistance to many antimicrobial agents. β-lactamase production is the most frequent mechanism for β-lactam resistance in P. aeruginosa. We evaluated the prevalence of β-lactamase genes in P. aeruginosa for classes A, C, and D by polymerase chain reaction, and investigated clonal diversity b...

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...

OBJECTIVES To gain insights into ampC transmission between bacterial strains. METHODS We examined the genetic context of 117 acquired ampC genes from 27119 Enterobacteriaceae collected between 1999 and 2007. Plasmid analysis was carried out by PCR-based replicon or relaxase typing, S1-PFGE and Southern hybridization. I-CeuI/PFGE was used for isolates not characterized by plasmid analysis. PCR...

The aim of the study was to determine the prevalence of AmpC producing E. coli, Klebsiellapneumoniae and Klebsiellaoxytoca and to evaluate and compare four different phenotypic methods viz; Modified Three Dimensional Test, AmpC Disk Test, AmpC Disk Test with Tris-EDTA and Inhibitor based detection test for the detection of AmpCβ-lactamases in these isolates, collected during a period of 2003 to...

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...

AmpC regulatory genes in 21 ceftazidime-resistant clinical isolates of Enterobacter cloacae (MICs of > or = 16 microg/ml) were characterized. All isolates exhibited AmpC overproduction due to AmpD mutation. Additionally, we found two AmpR mutants among the isolates. This is the first report of chromosomal ampR mutation in clinical isolates of E. cloacae.