The inhibition effect of several beta-lactam antibiotics on the uptake of [14C]benzylpenicillin (PCG) into isolated rat hepatocytes was studied. Monobasic beta-lactam antibiotics such as apalcillin, cloxacillin, nafcillin, piperacillin, cefmetazole, cefoperazone, cefpiramide and cephalothin significantly inhibited the uptake of PCG, while amphoteric beta-lactam antibiotics such as amoxicillin, ...

Significant advances have been made in the structure-based engineering of enzymes useful for beta-lactam antibiotic production. Structure-based engineering of penicillin G acylase and cephalosporin acylase has resulted in improved enzymes for use in enzymatic production processes. The structures of many other enzymes that could be used in the production of beta-lactam antibiotics, such as enzym...

objective(s) resistance to the new generation of cephalosporins which is mediated by extended-spectrum beta-lactamases (esbls) has been found among escherichia coli isolates throughout the world. these resistance genes and their producers, the micro-organisms carrying beta-lactamases, are responsible for serious clinical and therapeutic problems among inpatients and it is necessary to pay more ...

Reaction of the amino acid D-phenylalanine ethyl ester (4) with cinnamaldehyde gave chiral Schiff base 5, which underwent an asymmetric Staudinger [2+2] cycloaddition reaction with phthalimidoacetyl chloride to give the monocyclic beta-lactam 6 as a single stereoisomer. Ozonolysis of 6 followed by reduction with lithium aluminum tri(tert-butoxy) hydride afforded the hydroxymethyl beta-lactam 8....

BACKGROUND Emergence of extended-spectrum beta-lactamases (ESBLs) in Shigella species imparting resistance to third-generation cephalosporins is a growing concern worldwide. The aim of this study is to molecularly characterize the newly emerging beta-lactam resistant Shigella sonnei, specifically ESBLs in Lebanon, and compare them to beta-lactam sensitive isolates. METHODOLOGY We compared fiv...

An increase in the number of tuberculosis cases caused by multiple-drug-resistant strains of Mycobacterium tuberculosis has stimulated search for new antituberculous agents. Beta-lactam antibiotics, traditionally regarded as ineffective against tuberculosis, merit consideration. Four major penicillin-binding proteins (PBPs) with approximate molecular sizes of 94, 82, 52, and 37 kDa were detecte...

conclusions the results of this study phenotypically and genotypically confirmed the high frequency of esbl-producing strains, such as the ctx-m and ctx-m-1 genes, among enterobacteriaceae isolates in our region. therefore, use of antibiotic susceptibility testing for the detection of esbl isolates prior to the prescription of beta-lactam antibiotics is recommended. this could help prevent the ...