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Oxidative Medicine and Cellular Longevity
Volume 2012, Article ID 717843, 10 pages
Review Article

The Role of Hydrogen Peroxide in Environmental Adaptation of Oral Microbial Communities

1Department of Periodontics, College of Dentistry, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
2Department of Microbiology and Immunology, College of Medicine, University of Oklahoma Health Sciences Center, BMSB 907, 940 Stanton L Young Boulevard, Oklahoma City, OK 73104, USA

Received 10 April 2012; Accepted 11 May 2012

Academic Editor: Ivan Spasojevic

Copyright © 2012 Lin Zhu and Jens Kreth. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Oral streptococci are able to produce growth-inhibiting amounts of hydrogen peroxide (H2O2) as byproduct of aerobic metabolism. Several recent studies showed that the produced H2O2 is not a simple byproduct of metabolism but functions in several aspects of oral bacterial biofilm ecology. First, the release of DNA from cells is closely associated to the production of H2O2 in Streptococcus sanguinis and Streptococcus gordonii. Extracellular DNA is crucial for biofilm development and stabilization and can also serve as source for horizontal gene transfer between oral streptococci. Second, due to the growth inhibiting nature of H2O2, H2O2 compatible species associate with the producers. H2O2 production therefore might help in structuring the initial biofilm development. On the other hand, the oral environment harbors salivary peroxidases that are potent in H2O2 scavenging. Therefore, the effects of biofilm intrinsic H2O2 production might be locally confined. However, taking into account that 80% of initial oral biofilm constituents are streptococci, the influence of H2O2 on biofilm development and environmental adaptation might be under appreciated in current research.