نتایج جستجو برای: lactamase
تعداد نتایج: 12815 فیلتر نتایج به سال:
Eighty-nine Staphylococcus aureus strains were grouped according to their susceptibility or resistance to methicillin and oxacillin. The role of beta-lactamase in borderline methicillin resistance was confirmed by tests with beta-lactamase inhibitors, particularly when salt-supplemented medium was used. A penicillin-binding protein assay indicated that borderline methicillin-resistant S. aureus...
In competition assays for radiolabeled penicillin, penicillin-binding proteins (PBPs) 4, 7a, and 7b showed very high affinities for strong inducers of AmpC beta-lactamase. Loss of PBP 4 resulted in diminished inducibility. This suggests that if PBPs are involved in induction of AmpC beta-lactamase, there is probably a redundancy in function among the different PBPs.
Three Haemophilus parainfluenzae strains isolated from the urogenital tract harbored a beta-lactamase-coding 3.2-megadalton plasmid identical, by restriction endonuclease digestion and hybridization with radioactive and biotin-labeled probes specific for the TEM-1 beta-lactamase and TnA sequences, to the 3.2-megadalton "African-type" plasmid found in Neisseria gonorrhoeae.
1. Yigit H, Queenan AM, Anderson GJ et al. Novel carbapenemhydrolyzing b-lactamase, KPC-1, from a carbapenem-resistant strain of Klebsiella pneumoniae. Antimicrob Agents Chemother 2001; 45: 1151–61. 2. Smith Moland E, Hanson ND, Herrera VL et al. Plasmidmediated, carbapenem-hydrolysing b-lactamase, KPC-2, in Klebsiella pneumoniae isolates. J Antimicrob Chemother 2003; 51: 711–4. 3. Yigit H, Que...
A number of characteristics were determined with a new automated method for a partially purified beta-lactamase from Vibrio parahaemolyticus. The enzyme had a molecular weight of 28,000 by gel filtration, a pH optimum between 6.5 and 7.0, and a temperature optimum at 36 degrees C. With penicillin G as the substrate, the K(m) value for the beta-lactamase was 54.4 muM. The beta-lactamase was inhi...
Clavulanate is a broad-spectrum beta-lactamase inhibitor, with activity against many of the chromosomally and plasmid-mediated beta-lactamases of both Gram-positive and Gram-negative bacteria. Although clavulanate has minimal antibacterial activity in vitro, accumulating evidence suggests that it may have an effect on pathogenic bacteria regardless of beta-lactamase production. Like other beta-...
There are many examples of two penicillins acting synergistically, usually by one competitively inhibiting beta-lactamase, thus protecting the other from inactivation. There are few reports on penicillins antagonizing each other. Eight strains of three genera (Proteus, Escherichia, Pseudomonas) isolated at Boston City Hospital or Institut Pasteur, Paris, showed antagonism of carbenicillin or am...
beta-Lactamases represent the major resistance mechanism of gram-negative bacteria against beta-lactam antibiotics. The amino acid sequences of these proteins vary widely, but all are located in the periplasm of bacteria. In this study, we investigated the translocation mechanism of representative beta-lactamases in an Escherichia coli model. N-terminal signal sequence analyses, antibiotic acti...
OXA-48 beta-lactamase producers are emerging as an important threat mostly in the Mediterranean area. We report here the molecular epidemiology of a collection of OXA-48 beta-lactamase-positive enterobacterial isolates (n=107) recovered from European and north-African countries between January 2001 and December 2011. This collection included 67 Klebsiella pneumoniae, 24 Escherichia coli and 10 ...
BACKGROUND Metallo-β-lactamase-production among Gram-negative bacteria, including Pseudomonas aeruginosa, has become a challenge for treatment of infections due to these resistant bacteria. OBJECTIVES The aim of the current study was to evaluate the metallo-β-lactamase-production and carriage of bla-VIM genes among carbapenem-resistant P. aeruginosa isolated from burn wound infections. PATI...
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