Background: Borderline methicillin resistance in Staphylococcus aureus is due to β-lactamase overproduction and/or specific methicillinases. Methods: β-Lactamase activity in culture supernatants and in cytoplasmic membrane fractions was estimated by bioassay and by SDS-PAGE combined with nitrocefin assay. Results: During the investigation of borderline methicillin-resistant Staphylococcus aureus (BORSA) strains VU94 and 822 two β-lactamases were detected in the membranes, with molecular weights of 13 and 30 kDa. The latter could be found in the culture supernatants, too. In the presence of globomycin, this enzyme disappeared from the membrane, and the oxacillin-hydrolyzing activity of the membrane decreased to the level of susceptible strains. Both β-lactamases were detected in the methicillin-resistant Staphylococcus aureus strain studied, but the susceptible strains possessed only the first enzyme. Conclusions: The 30-kDa β-lactamase proved to be a methicillinase, and it can be one of the main causes of the borderline phenotype of BORSA strains. The other enzyme is one of the smallest β-lactamases published to date.

This content is only available via PDF.
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.