Four novel oxapenem compounds (i.e., AM-112, AM-113, AM-114, and AM-115) were investigated for their beta-lactamase inhibitory activity against a panel of isolated class A, C, and D enzymes, which included expanded-spectrum beta-lactamase enzymes (ESBLs). The oxapenems were potent beta-lactamase inhibitors. Activity varied within the group, with AM-113 and AM-114 proving to be the most active c...

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...

In 1996, Serratia marcescens KU3838 was isolated from the urine of a patient with a urinary tract infection at a hospital in northern Japan and was found to contain the plasmid pKU501. Previously, we determined that pKU501 carries bla(IMP) and the genes for TEM-1-type beta-lactamases as well as producing both types of beta-lactamases (H. Yano, A. Kuga, K. Irinoda, R. Okamoto, T. Kobayashi, and ...

A new insertion method for probing protein functional organization was developed. The method relies on the random insertion of transposon Tn 4430 and subsequent in vitro deletion of the bulk of the transposon after which a 15 bp insertion remains within the target gene. This results in pentapeptide insertions randomly distributed in the target protein. Characterization of 23 pentapeptide insert...

BACKGROUND Emergence of extended-spectrum beta-lactamases (ESBLs) in Shigella species imparting resistance to third-generation cephalosporins is a growing concern worldwide. The aim of this study is to molecularly characterize the newly emerging beta-lactam resistant Shigella sonnei, specifically ESBLs in Lebanon, and compare them to beta-lactam sensitive isolates. METHODOLOGY We compared fiv...

The clinical strain Escherichia coli TO799 was resistant to penicillin-clavulanate combinations and ceftazidime and was not reproducibly detected as an extended-spectrum -lactamase (ESBL) according to the standards of the Clinical Laboratory Standards Institute (CLSI; formerly NCCLS) and the national guidelines of the French Society for Microbiology (Comité de l’Antibiogramme de la Société Fran...

Clavulanic acid, sulbactam, and tazobactam are inhibitors of a variety of plasmid-mediated beta-lactamases. However, inhibition data for these three inhibitors with a wide range of different plasmid-mediated beta-lactamases have not yet been compared under the same experimental conditions. A number of groups have inferred that clavulanic acid inhibits extended-spectrum TEM and SHV beta-lactamas...

Isolates of extended-spectrum beta-lactamase (ESBL)-producing Salmonella typhimurium were recovered from children admitted to the IbnRochd University Hospital of Casablanca in 1994. These isolates produced TEM-3 as shown by PCR, isoelectric focusing and sequencing. Production of TEM-3 and resistance to gentamicin were encoded by a 10 kb plasmid that could be transferred by conjugation and trans...