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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TL;DR: The practice of discontinuing administration of the aminoglycoside antibiotic when group B streptococcal infection is confirmed should be re-evaluated.
89 citations
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TL;DR: There is no known transporter of benzylpenicillin despite its large production in industrial strains, and compartmentalization implies intracellular transport of isopenicillin N (in the penicillin pathway) or isopenICillin N and penicillins N in the cephalosporin route.
Abstract: Penicillins and cephalosporins are β-lactam antibiotics widely used in human medicine. The biosynthesis of these compounds starts by the condensation of the amino acids L-α-aminoadipic acid, L-cysteine and L-valine to form the tripeptide δ-L-α-aminoadipyl-l-cysteinyl-D-valine catalysed by the non-ribosomal peptide 'ACV synthetase'. Subsequently, this tripeptide is cyclized to isopenicillin N that in Penicillium is converted to hydrophobic penicillins, e.g. benzylpenicillin. In Acremonium and in streptomycetes, isopenicillin N is later isomerized to penicillin N and finally converted to cephalosporin. Expression of genes of the penicillin (pcbAB, pcbC, pendDE) and cephalosporin clusters (pcbAB, pcbC, cefD1, cefD2, cefEF, cefG) is controlled by pleitropic regulators including LaeA, a methylase involved in heterochromatin rearrangement. The enzymes catalysing the last two steps of penicillin biosynthesis (phenylacetyl-CoA ligase and isopenicillin N acyltransferase) are located in microbodies, as shown by immunoelectron microscopy and microbodies proteome analyses. Similarly, the Acremonium two-component CefD1-CefD2 epimerization system is also located in microbodies. This compartmentalization implies intracellular transport of isopenicillin N (in the penicillin pathway) or isopenicillin N and penicillin N in the cephalosporin route. Two transporters of the MFS family cefT and cefM are involved in transport of intermediates and/or secretion of cephalosporins. However, there is no known transporter of benzylpenicillin despite its large production in industrial strains.
89 citations
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TL;DR: A comparison with isolates of enterococci obtained in 1968 revealed that there has been a decrease in prevalence of high-level resistance among organisms isolated from wound cultures in 1976, however, no decrease in resistance to streptomycin or kanamycin was demonstrated among blood or urine isolates.
Abstract: Two hundred and three recent clinical isolates of enterococci were tested for susceptibility to streptomycin, kanamycin, amikacin, gentamicin, sisomicin, and tobramycin. Depending upon the source of the isolate, 36 to 54% of the enterococci demonstrated high-level resistance (minimal inhibitory concentration, >2,000 μg/ml) to streptomycin, 16 to 49% to kanamycin, and 0 to 14% to amikacin. None of the strains was highly resistant to gentamicin, sisomicin, or tobramycin. A comparison with isolates of enterococci obtained in 1968 revealed that there has been a decrease in prevalence of high-level resistance among organisms isolated from wound cultures in 1976. However, no decrease in resistance to streptomycin or kanamycin was demonstrated among blood or urine isolates. Penicillin, combined with gentamicin, sisomicin, or tobramycin, was synergistic against all 10 strains of Streptococcus faecalis subjected to formal testing. For streptomycin and kanamycin, the presence or absence of synergism with penicillin correlated with the absence or presence of high-level aminoglycoside resistance. High-level resistance to amikacin was seen in only 1 of the 10 strains. Nonetheless, combinations of penicillin plus amikacin failed to produce synergistic killing against 6 of the 10 strains. Indeed, the combination was synergistic only against those four strains that were susceptible to high levels of kanamycin.
89 citations
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TL;DR: In this paper, the authors tested all isolates of Streptococcus pneumoniae recovered from patients at St. Louis Children's Hospital for resistance to penicillin and other antibiotics.
Abstract: During a 12-month period we tested all isolates of Streptococcus pneumoniae recovered from patients at St. Louis Children's Hospital for resistance to penicillin and other antibiotics. Twenty-seven (20%) of 136 had relative penicillin resistance (minimum inhibitory concentration 0.1 to 1.0 μg/ml) an
88 citations
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TL;DR: In a penicillin-resistant clinical isolate, both genes are highly transcribed, but bla1 is the major contributor to high-level resistance to ampicillin.
Abstract: Expression of the bla1 and bla2 genes in an archetypal Bacillus anthracis strain is insufficient for penicillin resistance. In a penicillin-resistant clinical isolate, both genes are highly transcribed, but bla1 is the major contributor to high-level resistance to ampicillin. Differential expression of the bla genes is dependent upon strain background. Ciprofloxacin, doxycycline, and penicillin G are currently recommended by the Centers for Disease Control and Prevention and the Food and Drug Administration as therapeutics for inhalation and cutaneous anthrax (16). Prototypical Bacillus anthracis strains are susceptible to all three of these antibiotics. There have been no reports of naturally occurring ciprofloxacin- or doxycycline-resistant B. anthracis strains, but naturally occurring penicillin-resistant B. anthracis isolates have been reported (5, 19, 20, 32), and surveys of clinical and soil-derived strains have revealed penicillin G resistance in up to 16% of isolates tested (3, 6, 8, 10, 21, 25, 26).
88 citations