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.

Insertion of an extra amino acid is the main cause of the low affinity of penicillin‐binding protein 2 in penicillin‐resistant strains of Neisseria gonorrhoeae

Abstract: Non-beta-lactamase-producing, penicillin-resistant strains of Neisseria gonorrhoeae (CMRNG strains) produce altered forms of penicillin-binding protein 2 (PBP2) that have decreased affinity for penicillin. A feature of PBP2 from all CMRNG strains is the presence of an additional residue (Asp-345A) that is absent from PBP2 of penicillin-sensitive strains. The role of the additional aspartic acid residue in the decreased affinity of PBP2 is unclear as PBP2 of all previously examined CMRNG strains possess several other amino acid sequence alterations, in addition to the insertion of Asp-345A, compared to PBP2 of penicillin-sensitive strains. Site-directed mutagenesis has been used to insert the Asp-345A codon into the penA gene from a penicillin-sensitive gonococcus. The resulting penA gene expressed an altered form of PBP2 that had a decreased affinity for benzylpenicillin and was able to transform a penicillin-sensitive strain of N. gonorrhoeae to an increased level of resistance to benzylpenicillin. Insertion of amino acids other than aspartic acid did not produce forms of PBP2 that provided increased resistance to penicillin. Removal of the Asp-345A codon from the penA gene of a CMRNG strain reduced its ability to transform a penicillin-sensitive strain to an increased level of penicillin resistance. The reduction in the affinity of PBP2 in CMRNG strains is therefore largely, although not exclusively, due to the insertion of Asp-345A. Clinical isolates that produce altered forms of PBP2 that differ from that of penicillin-sensitive strains only in the insertion of Asp-345A have been identified.

Methicillin-resistant strains of Staphylococcus aureus; presence of identical additional penicillin-binding protein in all strains examined

Abstract: The methicillin-resistant strain of Staphylococcus aureus MR-1 previously reported to possess a penicillin-binding protein 3 (PBP 3) with a decreased affinity for β-lactam antibiotics was re-examined and, in common with other resistant strains, found to contain an additional PBP (PBP 2′). Expression of the additional protein, which has a very low affinity for β-lactams, was not influenced by temperature or osmolarity of the medium in contrast with strains examined previously. It was the only PBP still available to bind radioactive β-lactams and therefore still active enzymically when strain MR-1 was grown in the presence of concentrations of β-lactam antibiotics sufficient to kill sensitive strains of S. aureus. Penicillin-peptides derived by partial proteolysis of PBP 2′-penicillin complexes of MR-1 and 3 other methicillin-resistant strains appeared to be identical and different from the penicillin-peptides derived from PBP 1, PBP 2 and PBP 3, each of which gave rise to a unique series of peptides containing covalently-bound penicillin.

European Surveillance of Antimicrobial Consumption (ESAC): outpatient penicillin use in Europe

Abstract: BACKGROUND Data on outpatient penicillin use in Europe were collected from 25 countries within the ESAC project, funded by DG SANCO of the European Commission, using the WHO ATC/DDD methodology. METHODS For the period 1997-2003, data on outpatient use of systemic penicillins aggregated at the level of the active substance were collected and expressed in DDD (WHO, version 2004) per 1000 inhabitants per day (DID). Of the 'Penicillins' (J01C), outpatient use of narrow-spectrum penicillins (J01CE), broad-spectrum penicillins (J01CA), penicillinase-resistant penicillins (J01CF) and combinations with beta-lactamase inhibitors (J01CR) in 25 European countries was analysed in detail. RESULTS Total outpatient penicillin use in 2003 varied by a factor of 4 between the country with the highest (15.27 DID in Slovakia) and lowest use (3.86 DID in the Netherlands). Narrow-spectrum penicillins, broad-spectrum penicillins and combinations with beta-lactamase inhibitors were used most in 4, 12 and 9 countries, respectively. Penicillin use increased by more than 1 DID in nine countries, whereas it decreased by more than 1 DID in two countries (Czech Republic, France). An increase of the use of combinations with beta-lactamase inhibitors by more than 10% in 10 countries coincided with an equal decrease of broad-spectrum penicillins in seven countries and narrow-spectrum penicillins in three countries. CONCLUSION Penicillins represent the most widely used antibiotic class in all 25 participating countries; albeit with considerable variation of their use patterns. A distinct shift from narrow-spectrum penicillins to broad-spectrum penicillins, and specifically their combinations with beta-lactamase inhibitors, was observed during the period 1997-2003.