We constructed a library of beta-lactamases by recombining three naturally occurring homologs (TEM-1, PSE-4, SED-1) that share 34-42% sequence identity. Most chimeras created by recombining such distantly related proteins are unfolded due to unfavorable side-chain interactions that destabilize the folded structure. To enhance the fraction of properly folded chimeras, we designed the library usi...

conclusions the current study highlights that the high level of resistance to many antibacterial agents and a gradual increase in the degree of per, oxa-10, shv and tem esbls among the majority of imipenem resistant p. aeruginosa isolated from patients with burn infection is an enormous threat in burn centers in iran. results the results showed that the majority of isolates (88%) were multi-dru...

The sulbactam resistance rate in Acinetobacter baumannii has increased worldwide. Previous reports have shown that the β-lactamase bla TEM-1 confers resistance to sulbactam in A. baumannii. The purpose of this study was to examine whether other β-lactamases, including the Acinetobacter-derived cephalosporinase (ADC), OXA-23, OXA-24/72, and OXA-58 families, also contribute to sulbactam resistanc...

The most common mechanism of resistance to β-lactam antibiotics in Gram-negative bacteria is the production of β-lactamases that hydrolyze the drugs. Class A β-lactamases are serine active-site hydrolases that include the common TEM, CTX-M, and KPC enzymes. The TEM enzymes readily hydrolyze penicillins and older cephalosporins. Oxyimino-cephalosporins, such as cefotaxime and ceftazidime, howeve...

BACKGROUND & OBJECTIVE Extended-spectrum beta-lactamases (ESBLs) are rapidly evolving group of beta-lactamase enzymes produced by the Gram negative bacteria. These enzymes have been derived from TEM and SHV genes by mutations and have been well described in Klebsiella pneumoniae. Information on molecular types of ESBL positive Klebsiella sp. is lacking from India. We therefore undertook this st...

background: resistance to contemporary broad-spectrum b-lactam antibiotics mediated by extended-spectrum b-lactamases (esbls) is increasing worldwide. klebsiella pneumoniae , an important cause of nosocomial and community acquired urinary tract infections has rapidly become the most common esbl producing organism. we examined esbl production in urinary isolates of k. pneumoniae in relation to t...

Introduction: Extended-spectrum beta-lactamases (ESBLs) are rapidly evolving group of beta-lactamase enzymes commonly produced by the Gram negative bacteria, these enzymes have been derived from TEM and SHV genes by mutations. This study was done to look for TEM and SHV genes in ESBL positive E.coli and K. pneumoniae isolated from the cancer patients suffering with infections and admitted in a ...

Plasmid-encoded resistance to broad-spectrum cephalosporins and aztreonam is becoming a widespread phenomenon in clinical medicine. These antibiotics are inactivated by an array of different extended-spectrum beta-lactamases (ESBLs) which have evolved by point mutations of parental TEM or SHV beta-lactamases. In a previous study conducted during 1994-1995, SHV-2, SHV-2a and SHV-5 beta-lactamase...

β-Lactamases are produced by many modern bacteria as a mechanism of resistance toward β-lactam antibiotics, the most common antibiotics in use. β-Lactamases, however, are ancient enzymes that originated billions of years ago. Recently, proteins corresponding to 2- to 3-Gy-old Precambrian nodes in the evolution of Class A β-lactamases have been prepared and shown to be moderately efficient promi...