Resistant penicillin-binding proteins.
Low-affinity penicillin-binding proteins (PBPs), which participate in the beta-lactam resistance of several pathogenic bacteria, have different origins. Natural transformation and recombination events with DNA acquired from neighbouring intrinsically resistant organisms are responsible for the appearance of mosaic genes encoding two or three low-affinity PBPs in highly resistant strains of transformable microorganisms such as Neisseria and Streptococcus pneumoniae. Methicillin-resistant Staphylococcus aureus and coagulase-negative staphylococcal strains possess the mecA determinant gene, which probably evolved within the Staphylococcus genus from a closely related and physiologically functional gene that was modified by point mutations. The expression of mecA is either inducible or constitutive. A stable high-level resistant phenotype requires the synthesis of a normally constituted peptidoglycan. Enterococci have a natural low susceptibility to beta-lactams related to the presence of an intrinsic low-affinity PBP. Highly resistant enterococcal strains overexpress this PBP and/or reduce its affinity.
Hakenbeck
R
R
Institut für Mikrobiologie, Universität Kaiserslautern, Germany. hakenb@rhrk.uni-kl.de
Coyette
J
J
D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D002352:Carrier Proteins / Q000235:genetics*; D016984:Enterococcus faecium / Q000235:genetics; D006602:Hexosyltransferases; D008969:Molecular Sequence Data; D002267:Muramoylpentapeptide Carboxypeptidase / Q000235:genetics*; D009344:Neisseria gonorrhoeae / Q000235:genetics; D010403:Penicillin Resistance; D046915:Penicillin-Binding Proteins; D010406:Penicillins / Q000494:pharmacology*; D010458:Peptidyl Transferases; D013211:Staphylococcus aureus / Q000235:genetics; D013296:Streptococcus pneumoniae / Q000235:genetics
D001426:Bacterial Proteins; D002352:Carrier Proteins; D046915:Penicillin-Binding Proteins; D010406:Penicillins; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; D002267:Muramoylpentapeptide Carboxypeptidase