Topic
Penicillin
About: Penicillin is a research topic. Over the lifetime, 17916 publications have been published within this topic receiving 368480 citations. The topic is also known as: penicillin antibiotic & PCN.
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100 citations
TL;DR: The results suggest that the stimulating effect of enhanced organelle numbers may reflect an increase in the fluxes of penicillin and/or its precursors across the now much enlarged microbody membrane.
100 citations
TL;DR: Three clinical isolates from three New York City hospitals that demonstrated concomitant resistance to vancomycin (one VanA, two VanB phenotypes) and high-level resistance to penicillin were characterized.
Abstract: Enterococci are important nosocomial pathogens among which resistance to multiple antibiotics is being recognized with increasing frequency. We characterized three clinical isolates from three New York City hospitals that demonstrated concomitant resistance to vancomycin (one VanA, two VanB phenotypes) and high-level resistance to penicillin. Two Enterococcus faecium strains were intrinsically highly resistant to penicillin and showed very low affinity for penicillin of penicillin-binding protein 5. Unlike previously described glycopeptide-resistant enterococci, these strains were not hypersusceptible to beta-lactam agents after vancomycin induction, and combinations of penicillin and vancomycin were not synergistic against them. A third isolate, Enterococcus faecalis, produced beta-lactamase. Two of the three strains were also highly resistant to all aminoglycosides. Emergence of concomitant high-level resistance to multiple antibiotic classes among enterococci considerably narrows the therapeutic options for treatment of infections due to these opportunistic pathogens.
100 citations
TL;DR: Using PBP profiles, serotypes, and antibiotic resistance patterns, as well as data on isolation dates and sites, it was identified at least three groups of resistant strains that showed clear indication of clonal origin.
Abstract: In view of the worldwide emergence of penicillin-resistant pneumococci among clinical isolates it was of importance to examine a large number of strains to test the uniformity of the resistance mechanism. Among 160 clinical isolates of pneumococci (minimum inhibitory concentration [MIC], 0.005-16 micrograms/mL), susceptible strains showed a common pattern of five penicillin-binding proteins (PBPs) with high penicillin affinities (PBP 3 greater than 1A greater than or equal to 2A greater than 1B greater than 2B). PBPs 1A, 2A, and 2B (but not PBP 3) each showed distinct stepwise decreases in penicillin affinities parallel with increasing levels of antibiotic resistance. The number and molecular sizes of PBPs became variable in strains with MIC values greater than 1.0 microgram/mL; among 39 strains with a MIC of greater than or equal to 1.0 microgram/mL, 11 distinct and stable PBP patterns could be identified. Using PBP profiles, serotypes, and antibiotic resistance patterns, as well as data on isolation dates and sites, we identified at least three groups of resistant strains that showed clear indication of clonal origin.
100 citations
TL;DR: The exocellular DD-carboxypeptidases-transpeptidase that is excreted by Streptomyces R61 during growth, is very sensitive to penicillin and appears to be a good model for the study of the interaction between the enzyme, substrates and antibiotic.
100 citations