New mechanism for methicillin resistance in Staphylococcus aureus: clinical isolates that lack the PBP 2a gene and contain normal penicillin-binding proteins with modified penicillin-binding capacity

Détails

ID Serval
serval:BIB_F69AA64BA489
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
New mechanism for methicillin resistance in Staphylococcus aureus: clinical isolates that lack the PBP 2a gene and contain normal penicillin-binding proteins with modified penicillin-binding capacity
Périodique
Antimicrobial Agents and Chemotherapy
Auteur(s)
Tomasz  A., Drugeon  H. B., de Lencastre  H. M., Jabes  D., McDougall  L., Bille  J.
ISSN
0066-4804
Statut éditorial
Publié
Date de publication
11/1989
Peer-reviewed
Oui
Volume
33
Numéro
11
Pages
1869-74
Notes
Journal Article
Research Support, U.S. Gov't, P.H.S. --- Old month value: Nov
Résumé
Seventeen clinical isolates of Staphylococcus aureus (from the United States and Europe) selected for low (borderline)-level methicillin resistance (MIC of methicillin, 2 to 4 micrograms/ml; MIC of oxacillin, 0.5 to 8 micrograms/ml) were examined for their mechanisms of resistance. Five strains were typical of heterogeneous S. aureus: they gave positive reactions with a DNA probe specific for mec and contained a small fraction (10(-6] of highly resistant cells (MIC, greater than 100 micrograms/ml). The rest of the 12 strains were homogeneous with respect to their methicillin resistance: the MIC of methicillin for all cells was 2 to 4 micrograms/ml, and no cells for which MICs were 50 micrograms/ml or higher were detectable (less than 10(-9]. None of these strains reacted with the mec-specific DNA probe. One representative strain of each group was characterized in more detail. Strain CDC-1, prototype of heterogeneous methicillin-resistant S. aureus, contained penicillin-binding protein (PBP) 2a; its DNA could transform a methicillin-susceptible and novobiocin-resistant recipient to methicillin resistance with ca. 35% linkage to Novr. Introduction of the "factor X" determinant (K. Murakami and A. Tomasz, J. Bacteriol. 171:874-879, 1989) converted strain CDC-1 to high, homogeneous resistance. Strain CDC-6, prototype of the second group of isolates, showed completely homogeneous MICs of methicillin, oxacillin, and cefotaxime. The strain contained modified "normal" PBPs: PBPs 1 and 2 showed low drug reactivity (and/or cellular amounts), and PBP 4 was present in elevated amounts. No PBP 2a could be detected. DNA isolated from strain CDC-6 could transform the methicillin-susceptible and novobiocin-resistant strain to methicillin resistance in a multistep fashion, but this resistance showed no genetic linkage to the Nov marker. We suggest that staphylococci with borderline resistance may contain at least three different classes of mechanism: heterogeneous, methicillin-resistant S. aureus, PBPs of modified drug reactivities, and the previously reported hyperproduction of beta-lactamase (L.K. McDougal and C. Thornsberry, J. Clin Microbiol. 23:832-839, 1986).
Mots-clé
*Bacterial Proteins Carrier Proteins/*metabolism Cefotaxime/pharmacology DNA Probes *Hexosyltransferases Humans Methicillin/*pharmacology Muramoylpentapeptide Carboxypeptidase/*metabolism Oxacillin/pharmacology Penicillin Resistance Penicillin-Binding Proteins *Peptidyl Transferases Protein Binding Staphylococcal Infections/microbiology Staphylococcus aureus/*drug effects/genetics/metabolism Transformation, Bacterial
Pubmed
Web of science
Création de la notice
11/02/2008 13:40
Dernière modification de la notice
20/08/2019 17:23
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