PubMed · 9054330
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
S M Shatunov, Iu B Belousov. 1996. [Meropenem].. https://pubmed.ncbi.nlm.nih.gov/9054330/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
A short stereoselective synthesis of the acetoxy azetidinone (1), an important precursor of several biologically active beta-lactam antibiotics, has been accomplished in seven steps and 32.8% overall yield from the easily available and inexpensive (R) ethyl 3-hydroxybutanoate.
Escherichia coli HKY56, which demonstrated resistance to various beta-lactams except carbapenems, was isolated from the throat swab of an inpatient in 1994. Conjugal transfer of cephem resistance from HKY56 to E. coli CSH2 was not successful. Three cefotaxime-resistant E. coli clones harboring plasmid pMRE001, pMRE002, or pMRE003, each of which carried a 3.4-, 5.8-, or 6.2-kb EcoRI fragment insert, respectively, were obtained from HKY56. Although restriction analysis suggested their different origins, these clones showed similar profiles of resistance to various beta-lactams. The sequence of 10 amino acid residues at the N terminus of beta-lactamase purified from E. coli HB101(pMRE001) was identical to that of Toho-1. This Toho-1-like beta-lactamase-1 (TLB-1) was able to hydrolyze cefoperazone and cefotaxime efficiently, but it failed to hydrolyze cephamycins. A Toho-1-specific DNA probe was hybridized with three distinct EcoRI fragments derived from the chromosomal DNA of strain HKY56, and these fragments corresponded to DNA inserts carried by pMRE001, pMRE002, and pMRE003, respectively. PCR and Southern hybridization analysis suggested that all six cephem-resistant E. coli strains, strains HKY273, HKY285, HKY288, HKY305, HKY316, and HKY335, which were isolated in 1996 at the same hospital where strain HKY56 had been isolated, also possessed multiple Toho-1-like beta-lactamase (TLB) genes, and the hybridization patterns obtained with the Toho-1-specific probe were quite similar among these six isolates. The DNA fingerprinting patterns observed by pulsed-field gel electrophoresis revealed that among the E. coli isolates tested, all isolates except HKY56 possessed a similar genetic background. These findings suggested that E. coli strains that carry chromosomally multiplied TLB genes may have been proliferating and transmitted among patients in the same hospital.
Carbapenems L-749,345 and imipenem had the lowest MICs at which 90% of isolates were inhibited (0.5 microg/ml) of 14 antimicrobial agents tested against 76 multiresistant gram-negative clinical isolates with TEM- or SHV-type extended-spectrum beta-lactamases and chromosomal or plasmid-determined AmpC beta-lactamases, but the MIC of L-749,345 for one isolate of Klebsiella pneumoniae was 16 microg/ml.