Blood cultures drawn from a patient with clinically diagnosed invasive meningococcal disease, who had been previously administered benzylpenicillin, had beta-lactamases added to increase the probability of recovery of the causative organism. The blood cultures subsequently yielded Neisseria meningitidis but direct susceptibility tests by the comparative disk diffusion method demonstrated greatl...

During the last decade, Gram-negative clinical isolates, including Enterobacteriaceae, Pseudomonas spp. and Acinetobacter spp. with decreased susceptibility to carbapenems, have been increasingly reported in Europe. Carbapenem resistance in Enterobacteriaceae may be related either to the association of a decrease in bacterial outer-membrane permeability with overexpression of b-lactamases posse...

background: failure in the treatment of burn patients infected with pseudomonas aeruginosa could happen as a result of the acquisition of antibiotic resistance, including carbapenems. objectives: the aim of the present study was to investigate the phenotypic and genotypic characteristics of the pseudomonas aeruginosa strains, isolated from burn patients. patients and methods: during a 12 month ...

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...

Extended-spectrum β-lactamases (ESBL) producing bacteria have been increasingly reported in both hospital and community patients. Production of ESBLs is the major mechanism of resistance to oxymino-cephalosporins and aztreonam in Gram-negative bacteria. Recently a new family of ESBLs with predominant activity against cefotaxime (CTX-M β-lactamases) has been reported. Over 80 CTX-M enzymes have ...

Ligase chain reaction (LCR) is a recently developed technique that employs a thermostable ligase and allows for the discrimination of DNA sequences differing in only a single base pair. The method has been adapted and applied to differentiation of blaSHV genes. We have developed an LCR typing method to characterize point mutations in genes for SHV-derived extended-spectrum b-lactamases with fou...

Resistance to beta-lactam antibiotics has been a problem for as long as these drugs have been used in clinical practice. In clinically significant bacteria the most important mechanism of resistance is the production of one or more beta-lactamases, enzymes that hydrolyse the beta-lactam bond characteristic of this family of antibiotics. Prominent among the beta-lactamases produced by the Entero...

The beta-lactamases of six Legionella species were characterized by isoelectric focusing, gel filtration, and substrate profiles. Fifteen strains of L. bozemanii, L. dumoffii, L. gormanii, L. longbeachae, and L. pneumophila produced beta-lactamases active against nitrocefin. L. micdadei enzymes previously reported to be beta-lactamase negative caused a very slow pH-dependent breakdown of nitroc...

OBJECTIVES Widespread use of β-lactam antibiotics could cause resistance to this group of antibiotics in pathogenic bacteria through the production of the enzyme β-lactamases. The aim of this study is to determine the molecular detection of AmpC β-lactamases among clinical Escherichia coli isolated from Ilam hospitals in Ilam, Iran. METHODS One hundred and twelve clinical isolates of E. coli ...

1. Bonnet R. Growing group of extended-spectrum b-lactamases: the CTX-M enzymes. Antimicrob Agents Chemother 2004; 48: 1–14. 2. Weill FX, Perrier-Gros-Claude JD, Demartin Met al. Characterization of extended-spectrum-b-lactamase (CTX-M-15)-producing strains of Salmonella enterica isolated in France and Senegal. FEMS Microbiol Lett 2004; 238: 353–8. 3. Bouallègue-Godet O, Ben Salem Y, Fabre L et...