Analysis of pH–Driven Disruption of Oral Microbial Communities in vitroBradshaw D. · Marsh P.D.
Research Division, CAMR, Salisbury, Wiltshire, UK
Do you have an account?
- Rent for 48h to view
- Buy Cloud Access for unlimited viewing via different devices
- Synchronizing in the ReadCube Cloud
- Printing and saving restrictions apply
Rental: USD 8.50
Cloud: USD 20.00
Previously, a mixed culture chemostat system was used to demonstrate that the pH generated from carbohydrate metabolism, rather than carbohydrate availability per se, was responsible for the shifts observed in the oral microflora which are associated with high carbohydrate diets and the development of dental caries. The aim of this study was to determine more accurately the microbially generated pH at which such shifts occurred. Nine oral bacteria were grown in three independent chemostats, and pulsed with glucose on 10 consecutive days. In one chemostat, pH control was discontinued for 6 h, and the pH fall was restricted to a minimum value of pH 5.5; the pH fall was arrested in the other two chemostats at either pH 5.0, or at pH 4.5. When the pH was allowed to fall, the numbers and proportions of Streptococcus mutans and Lactobacillus rhamnosus increased; this increase was directly related to the magnitude of the pH fall. Veillonella dispar was the most numerous organism following all glucose pulsing regimes, especially at low pH. The increase in proportions of acidogenic bacteria was accompanied by a fall in the proportions of acid–sensitive species (Fusobacterium nucleatum, Prevotella nigrescens, Streptococcus gordonii and Streptococcus oralis). The counts of these species were relatively stable between pH 5.5 and 4.5, but were markedly reduced when the pH fell below pH 4.5; Neisseria subflava could not persist in the culture at pH 4.5 or below. The data suggest that the disruption of communities associated with glucose metabolism and low pH can be explained in terms of a two–stage process. A fall in pH to a value between pH 5.5 and 4.5 may allow the enrichment of potentially cariogenic species, whilst permitting species associated with health to remain relatively unaffected. A further reduction in pH (
Article / Publication Details
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 or, in the case of photocopying, direct payment of a specified fee to the Copyright Clearance Center.
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.