Activity of simulated cefditoren urinary concentrations was determined against seven Escherichia coli isolates. Bactericidal activity was obtained from 4 to 24 h against TEM-1 (penicillinase production/hyperproduction), TEM-34 (IRT-6), and TEM-116 (extended-spectrum beta-lactamase [ESBL]) and from 6 to 8 h against SHV/TEM-116 (ESBL) but never against SHV/TEM-1 (ESBL). Extension of bactericidal ...

An Italian nationwide survey was carried out to assess the prevalences and the antimicrobial susceptibilities of members of the family Enterobacteriaceae producing extended-spectrum beta-lactamases (ESBLs). Over a 6-month period, 8,015 isolates were obtained from hospitalized patients and screened for resistance to extended-spectrum cephalosporins and monobactams. On the basis of a synergistic ...

Using an isogenic system, we have determined the impact that the four promoters known to control bla(TEM) gene expression have on beta-lactamase activity. For both TEM-1 and TEM-30, this activity gradually increased in relation to the presence of promoters P3, Pa/Pb, and P4 upstream of the corresponding gene. Promoter P5, only found upstream of the bla(TEM-1B) gene, was related to the highest e...

Four ceftazidime-resistant Escherichia coli strains were isolated from elderly nursing home patients in a New York hospital during 1993. Strains MCQ-2, MCQ-3, and MCQ-4 were determined to be identical by pulsed-field gel electrophoresis and plasmid profiles, whereas strain MCQ-1 was unique. Strain MCQ-1 was determined to produce a TEM-10 beta-lactamase. Strains MCQ-2, MCQ-3, and MCQ-4 were also...

The beta-lactamases of six strains of Acinetobacter baumannii were investigated using analytical isoelectric focusing, and the MIC values for 16 beta-lactam antibiotics determined against the strains. Three strains produced a chromosomal cephalosporinase (pI > 8.5), one strain a CARB-5 beta-lactamase (pI = 6.35), one strain a TEM-1 penicillinase (pI = 5.4) as well as a cephalosporinase (pI > 8....

AIM To determine the genetic basis and types of beta-lactamase encountered among enterobacterial isolates of wild pets from the animal exhibit. MATERIALS AND METHODS A total of 17 beta-lactamase-producing enterobacteria recovered from fecal samples of wild pet animals were analyzed for a selected beta-lactamase gene by polymerase chain reaction. RESULTS Molecular analysis identified one or ...

The expression of Vitreoscilla hemoglobin (VHb) in Escherichia coli JM101 (pRED2) causes the incorporation of the TEM beta-lactamase precursor into cytoplasmic inclusion bodies (IBs). Less pre-beta-lactamase is translocated and processed to its mature, periplasmic form in the strain coexpressing VHb than in the control strain E. coli JM101(pUC19) not expressing VHb. When cells are grown in a sp...

Beta-lactamase confers resistance to penicillin-like antibiotics by hydrolyzing their beta-lactam bond. To combat these enzymes, inhibitors covalently cross-linking the hydrolytic Ser70 to Ser130 were introduced. In turn, mutant beta-lactamases have emerged with decreased susceptibility to these mechanism-based inhibitors. Substituting Ser130 with glycine in the inhibitor-resistant TEM (IRT) mu...