TEM- or SHV-type extended-spectrum beta-lactamases(ESBLs) are of clinical concern in Europe and the United States, whereas bacterial strains producing such types of ESBLs had not been reported in Japan for many years. Toho-1, a different type class A ESBL, has been reported in 1995, in which any prototypical enzyme has not been identified so far. At present Toho-1 is the major ESBL in Japan, ho...

A new beta-lactamase inhibitory protein (BLIP-I) from Streptomyces exfoliatus SMF19 was purified and characterized. The molecular mass of BLIP-I was estimated to be 17.5 kDa by gel filtration fast protein liquid chromatography. The N-terminal sequence was NH(2)-Asn-Ser-Gly-Phe-Ser-Ala-Glu-Lys-Tyr-Glu-Gln-Ile-Gln-Phe-Gly. BLIP-I inhibited Bacto(R) Penase (Difco), and plasmid encoded TEM-1 beta-l...

Beta-lactamase acquisition is the most prevalent basis for Gram-negative bacteria resistance to the beta-lactam antibiotics. The mechanism used by the most common class A Gram-negative beta-lactamases is serine acylation followed by hydrolytic deacylation, destroying the beta-lactam. The ab initio quantum mechanical/molecular mechanical (QM/MM) calculations, augmented by extensive molecular dyn...

Two isolates of Klebsiella pneumoniae possessing both TEM-1 and SHV-2 beta-lactamases were isolated from patients at the Cleveland Clinic in 1988. The beta-lactamases were discriminated and identified by using substrate hydrolysis data and an isoelectric focusing procedure in which the gel was overlaid with beta-lactamase inhibitors.

By Etest determination of the susceptibilities of 229 Haemophilus influenzae strains isolated in Korea to 10 antibiotics, the isolates were found to be antibiotic nonsusceptible in the following order: ampicillin (58.1%), trimethoprim-sulfamethoxazole (52%), cefaclor (41.1%), clarithromycin (25.8%), chloramphenicol (14.0%), amoxicillin-clavulanic acid (13.5%), meropenem (11.7%), cefixime (10.9%...

Antimicrobial susceptibility patterns and beta-lactam resistance mechanisms of 544 Haemophilus influenzae isolates through the nationwide Acute Respiratory Infections Surveillance (ARIS) network in Korea during 2005 and 2006 were determined. Resistance to ampicillin was 58.5%, followed by resistance to cefuroxime (23.3%), clarithromycin (18.7%), cefaclor (17.0%), amoxicillin-clavulanate (10.4%)...

The bla(TEM-1) beta-lactamase gene has become widespread due to the selective pressure of beta-lactam use and its stable maintenance on transferable DNA elements. In contrast, bla(SME-1) is rarely isolated and is confined to the chromosome of carbapenem-resistant Serratia marcescens strains. Dissemination of bla(SME-1) via transfer to a mobile DNA element could hinder the use of carbapenems. In...

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...