beta-Lactamase inhibitors such as sulbactam are beta-lactam compounds that have low antimicrobial activity but are able to inhibit enzymes (beta-lactamases) that destroy beta-lactam antibiotics like penicillins and cephalosporins. The main activity of beta-lactamase inhibitors is directed against plasmid-mediated transferable enzymes and various extended-spectrum enzymes. Sulbactam is also acti...

Quorum sensing is a cell-cell communication mechanism that is involved in the regulation of biological functions such as luminescence, virulence, and biofilm formation. Quorum-quenching enzymes, which interrupt quorum-sensing signaling through degradation of quorum-sensing molecules, have emerged as a new approach to controlling and preventing bacterial virulence and pathogenesis. In an effort ...

The Aeromonas hydrophila AE036 chromosome contains a cphA gene encoding a metallo-beta-lactamase which is highly active against carbapenem antibiotics such as imipenem. Here we show that the cphA gene product shares inhibitory similarities with a mammalian zinc peptidase, membrane dipeptidase (MDP; dehydropeptidase I). Both enzymes are able to hydrolyze imipenem and are inhibited by cilastatin....

In the Calgary Health Region during 2000-2003, prospective, active, population-based laboratory surveillance for all cefoxitin-resistant Escherichia coli isolates was performed. Isolates were screened with an inhibitor-based disk test, and plasmid-mediated types were identified by multiplex PCR with sequencing. A total of 369 AmpC beta-lactamase-producing E. coli isolates were identified; annua...

Antibody directed enzyme prodrug therapy (ADEPT) utilizing β-lactamase is a promising treatment strategy to enhance the therapeutic effect and safety of cytotoxic agents. In this method, a conjugate (antibody-β-lactamase fusion protein) is employed to precisely activate nontoxic cephalosporin prodrugs at the tumor site. A major obstacle to the clinical translation of this method, however, is th...

Antibiotic resistance among Escherichia coli isolates from diarrhoeal disease in cattle was studied. Many of the isolates were multiply resistant to beta-lactams, including expanded-spectrum cephalosporins, aminoglycosides, sulphonamides, tetracycline and fluoroquinolones. In many of the isolates, IEF revealed a strong beta-lactamase band compatible with overexpression of the AmpC beta-lactamas...

The class A PSE-4 beta-lactamase was used for studying the importance of amino acids in the omega (Omega) loop and its interactions for hydrolysis of beta-lactam antibiotics. By cassette mutagenesis, we replaced the amino acids 163-179 Omega loop in PSE-4 with TEM-1, SHV-1 and Streptomyces albus G beta-lactamase Omega loops. Phenotypic analysis of Escherichia coli recombinants expressing the Om...

β-Lactam resistance in Acinetobacter baumannii presents one of the greatest challenges to contemporary antimicrobial chemotherapy. Much of this resistance to cephalosporins derives from the expression of the class C β-lactamase enzymes, known as Acinetobacter-derived cephalosporinases (ADCs). Currently, β-lactamase inhibitors are structurally similar to β-lactam substrates and are not effective...

Presence of Bush class C enzymes in uropathogenic strains of Klebsiellapneumoniae & E.coli resistant to extended spectrum cephalosporins is anemerging threat to clinical therapeutics. These resistant strains result inconsiderable treatment failure and cannot be detected by routine antibioticsensitivity screening methods. An effort was therefore made to study AmpC βlactamase ...