In this study, 78 isolates of Escherichia coli isolated from Korean beef cattle farms were investigated for the production of extended-spectrum β-lactamase (ESBL) and/or AmpC β-lactamase. In the disc diffusion test with ampicillin, amoxicillin, cephalothin, ceftiofur, cefotaxime, ceftazidime, and cefoxitin, 38.5% of the isolates showed resistance to all of ampicillin, amoxicillin, and cephaloth...

We have developed a simple and general method that allows for the facile recombination of distantly related (or unrelated) proteins at multiple discrete sites. To evaluate the sequence-independent site-directed chimeragenesis (SISDC) method, we have recombined beta-lactamases TEM-1 and PSE-4 at seven sites, examined the quality of the chimeric genes created, and screened the library of 2(8) (25...

BACKGROUND & OBJECTIVES Extended spectrum beta lactamases (ESBLs) have been observed in virtually all the species of family Enterobacteriaceae. The enzymes are predominantly plasmid mediated and are derived from broad-spectrum beta lactamase TEM-1, TEM-2 or SHV-1 by a limited number of mutations. This study was undertaken to characterize ESBL producers among Escherichia coli and Klebsiella pneu...

in modern medical processes, new antimicrobial drugs are being widely used in order to rapid and essential eradication of resistant bacterial strains. broad-spectrum beta-lactamases are enzymes originated from mutations in the common plasmid genes mediators for beta-lactamases such as tem-1, tem-2, and shv-1 are transferred among bacterial species. the genes coding the production of esbl are of...

Monobactams containing 3 beta-aminothiazolyl oxime side chains (SQ 81,377, SQ 81,402, azthreonam, and SQ 26,917) have poor affinities for the broad-spectrum beta-lactamases TEM-2 and K1. Addition of a 4-methyl substituent significantly increased stability to hydrolysis by these enzymes. P99 cephalosporinase from Enterobacter cloacae was strongly inhibited by the monobactams. Interaction of azth...

A new analytical mutagenesis technique is described that involves randomizing the DNA sequence of a short stretch of a gene (3-6 codons) and determining the percentage of all possible random sequences that produce a functional protein. A low percentage of functional random sequences in a complete library of random substitutions indicates that the region mutagenized is important for the structur...

AIM During 2010-2011, six Providencia spp. (five Providencia stuartii and one Providencia rettgeri) urine isolates with unusual resistance phenotype were collected from various hospital units at the University Hospital Split in Croatia. The aim of the study was to analyze the mechanisms of resistance to expanded-spectrum cephalosporins. METHODS The antimicrobial susceptibility to a wide range...

Background & Aims: Organisms producing TEM-β-lactamase are emerging around the world as a source of resistance to β-lactam antibiotics such as three generation cephalosporins. In this study, we used a polymerase chain reaction (PCR) to identify genes TEM for Extended-spectrum β-lactamase (ESBLs) producing clinical isolates of Klebsiella pneumonia from hospitals of Boro...

Molecular evolution has always been a subject of discussions, and researchers are interested in understanding how proteins with similar scaffolds can catalyze different reactions. In the superfamily of serine penicillin-recognizing enzymes, D-alanyl-D-alanine peptidases and beta-lactamases are phylogenetically linked but feature large differences of reactivity towards their respective substrate...

Extended-spectrum β-lactamases (ESBLs) prevalence was studied in the north of Portugal, among 193 clinical isolates belonging to citizens in a district in the boundaries between this country and Spain from a total of 7529 clinical strains. In the present study we recovered some members of Enterobacteriaceae family, producing ESBL enzymes, including Escherichia coli (67.9%), Klebsiella pneumonia...