The in vivo activity and source of beta-lactamase in sputum samples from 43 patients with cystic fibrosis (CF) during a 2-week antipseudomonal treatment were studied. A colorimetric method, based on the conversion of nitrocefin, was used for quantitation of the sputum beta-lactamase activity. beta-Lactamases in sputum were characterized by isoelectric focusing and inhibition profile and were co...

The in vitro activities of two new beta-lactam antibiotics, cefotaxime and moxalactam (LY127935), were compared with those of cefamandole, cefoxitin, cefuroxime, and ampicillin against both beta-lactamase-producing and non-beta-lactamase-producing isolates of Haemophilus influenzae. Both cefotaxime and LY127935 were highly active against all isolates irrespective of beta-lactamase production.

Carbapenems are group of extended-spectrum β-lactam antimicrobials frequently used for treating multidrug-resistant Gram-negative bacilli (GNB) infections. This study aimed at detecting and characterizing carbapenem resistance (CR) genes among GNB isolated from patients treated in neonatal intensive care unit (NICU) Mansoura University Children's Hospital (MUCH), Egypt. It is a prospec...

Concomitant with the extensive use of antibiotics, the number of multiple antibiotic-resistant strains has been increasing. Since resistance is mainly mediated by R plasmids, we undertook to investigate the characteristics of R plasmid-determined beta-lactamase in 6 Gram-negative rods. The beta-lactamase produced by each organism was classified by its substrate: type P which attacks penicillins...

A new beta-lactamase assay method with agar plates containing pyridinium-2-azo-p-dimethylaniline chromophore (PADAC) (50 microM), a beta-lactamase-labile, chromogenic cephalosporin, was examined. On the PADAC plates inoculated with beta-lactamase-producing gram-negative bacteria (10(4) CFU per spot) and incubated at 37 degrees C, a yellow zone showing hydrolysis of PADAC by beta-lactamase was f...

BACKGROUND The aims of this study were to confirm the presence of OmpK35 and OmpK36 in extended-spectrum beta-lactamase-producing and nonextended-spectrum beta-lactamase-producing Klebsiella pneumoniae and to determine the relationship between porin expression and resistance to third-generation cephalosporins. METHODS Fifty-two K. pneumoniae isolates were obtained and analyzed for extended-sp...