Mosaic-like structure of penicillin-binding protein 2 gene (PenA) in clinical isolates of Neissetia gonorrhoeae with reduced susceptibility to cefixime

Research Laboratories, Toyama Chemical Co., Ltd., 2-4-1, Shimookui, Japan.
Antimicrobial Agents and Chemotherapy (Impact Factor: 4.45). 01/2003; 46(12):3744-9. DOI: 10.1128/AAC.46.12.3744-3749.2002
Source: PubMed

ABSTRACT Neisseria gonorrhoeae strains with reduced susceptibility to cefixime (MICs, 0.25 to 0.5 micro g/ml) were isolated from male urethritis patients in Tokyo, Japan, in 2000 and 2001. The resistance to cephems including cefixime and penicillin was transferred to a susceptible recipient, N. gonorrhoeae ATCC 19424, by transformation of the penicillin-binding protein 2 gene (penA) that had been amplified by PCR from a strain with reduced susceptibility to cefixime (MIC, 0.5 micro g/ml). The sequences of penA in the strains with reduced susceptibilities to cefixime were different from those of other susceptible isolates and did not correspond to the reported N. gonorrhoeae penA gene sequences. Some regions in the transpeptidase-encoding domain in this penA gene were similar to those in the penA genes of Neisseria perflava (N. sicca), Neisseria cinerea, Neisseria flavescens, and Neisseria meningitidis. These results showed that a mosaic-like structure in the penA gene conferred reductions in the levels of susceptibility of N. gonorrhoeae to cephems and penicillin in a manner similar to that found for N. meningitidis and Streptococcus pneumoniae.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Penicillin-binding proteins (PBPs) are the targets of -lactam antibiotics. These enzymes catalyze the last stages in the polymerization of peptidoglycan, the major constituent of the cell wall. The peptidoglycan, or murein, is a giant molecule, which forms a molecular mesh around the plasma membrane. Chains of tandemly repeated disaccharides form the glycan strands that are linked to each other by short peptide bridges. The discoveries of the PBPs and their cross-bridging mechanism were intimately intertwined. On the basis of studies of the effect of penicillin on peptidoglycan synthesis, it was concluded that cross-linking of the glycan chains resulted from a transpeptidation reaction, which is inhibited by -lactams (1, 2). The fi rst PBPs were isolated a few years later by covalent affi nity chromatography on penicillin- substituted resin (3). Some of these PBPs were dd- carboxypeptidases or endopeptidases rather than transpeptidases. In the intervening three decades, intense research has been carried out on PBPs, particularly on their role in the resistance to -lactams of some important pathogens such as Staphylococcus aureus, Enterococci and Streptococcus pneumoniae.
    FEMS microbiology reviews 03/2008; 32(2). DOI:10.1007/978-1-59745-180-2_13
  • 01/1970: pages 77-96;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Spectral analysis of functions obtained experimentally by three different methods is carried out. The methods are discrete Fourier transform (DFT), improved DFT, and a new method based on the classical Fourier analysis method. The analyzed waveforms are observed once as a sequence of samples (theoretical representation), and once as a sample and hold function (physical representation). The main points of the analysis are: calculation of the spectra using the different methods; obtaining approximated functions by the summation of the derived harmonics; and estimation of the errors in the approximation


Available from