Sub-inhibitory concentrations of lincomycin slightly inhibit growth of Escherichia coli carrying plasmid RP4 and cause a 2-fold increase in TEM-2 beta-lactamase. To analyze this effect, cultures were pulse-labeled with [3H]leucine, chased with non-radioactive leucine and immunoprecipitated with anti-beta-lactamase antiserum. The synthesis rate of beta-lactamase was two times higher in inhibited...

While most bacteria involved in dentoalveolar infection are highly susceptible to penicillin, some Prevotella strains exhibit resistance to this agent through the production of beta-lactamase. The production of beta-lactamase by Prevotella spp. is in turn associated with the expression of the genes cfxA and cfxA2. The aim of the present study was to determine the prevalence of cfxA and cfxA2 in...

We have studied the genetic basis of beta-lactamase production in eight strains of Haemophilus ducreyi isolated in diverse areas of the world. Beta-lactamase production in all strains was mediated by plasmids having a molecular mass of either 5.7 or 7.0 megadaltons. Plasmids of 5.7 megadaltons were shown to carry the entire sequence of pFA7, the beta-lactamase specifying plasmid found in isolat...

Nosocomial infections are proving to be a menace for the whole health care system, with methicillin resistant Staphylococcus aureus (MRSA) being very notorious causative agent. Along role of mecA gene producing penicillin-binding protein (PBP2a), production beta-lactamase enzyme by makes organism all β-lactam agents. This study aims at phenotypic detection resistance and β-Lactamase in S. isola...

The susceptibilities of 43 pharyngeal isolates of Capnocytophaga to beta-lactam antibiotics, alone or in combination with beta-lactamase inhibitors, were tested by an agar dilution method. The 34 beta-lactamase-positive strains were highly resistant to beta-lactams, but the intrinsic activities of clavulanate, tazobactam, and sulbactam against Capnocytophaga, even beta-lactamase producers, indi...

In contrast to most Staphylococcus aureus isolates in which the gene for staphylococcal beta-lactamase (blaZ) is plasmid borne, isolates typeable by group II bacteriophages frequently carry blaZ on the chromosome. Furthermore, the chromosomal gene encodes the type B variant of staphylococcal beta-lactamase for which the nucleotide and deduced amino acid sequences have not yet been reported. To ...

A new class of small nonfluorescent fluorogenic substrates becomes brightly fluorescent after beta-lactamase hydrolysis with up to 153-fold enhancement in the fluorescence intensity. Less than 500 fM of beta-lactamase in cell lysates can be readily detected, and beta-lactamase expression in living cells can be imaged with a red fluorescence derivative. These new fluorogenic substrates should fi...

The Gram-positive bacterium B. cereus produces both -lactamase I, a class A serine enzyme, and -lactamase II, a zinc dependent enzyme of class B. Crystallographic studies of these two enzymes have shown that -lactamase I is homologous with the penicillin-sensitive D-alaD-ala carboxypeptidase-transpeptidase of Streptomyces R61 while -lactamase II has a hitherto unknown structure. New methods of ...

Using clinical strains of Serratia marcescens with low and high resistance to extended-spectrum beta-lactam antibiotics, the relative contribution of chromosomal beta-lactamase and defective outer membrane porins to resistance was determined. Low-level resistance was caused by overproduced beta-lactamase alone. High-level resistance was due to beta-lactamase overproduction and defects of porin ...