Sialic acid, periodontal pathogens and Tannerella forsythia: stick around and enjoy the feast!


Graham Philip Stafford, Oral and Maxillofacial Pathology, School of Clinical Dentistry, University of Sheffield, Claremont Crescent, Sheffield S10 2TA, UK Tel.: +44 11 4271 7959; fax: +44 11 4271 7959; E-mail:
Ashu Sharma, Department of Oral Biology, School of Dental Medicine, University at Buffalo, The State University of New York, 311 Foster Hall, Buffalo, NY 14214, USA Tel.: +1 716 829 2759; fax: +1 716 829 3942; E-mail:


Periodontal pathogens, like any other human commensal or pathogenic bacterium, must possess both the ability to acquire the necessary growth factors and the means to adhere to surfaces or reside and survive in their environmental niche. Recent evidence has suggested that sialic acid containing host molecules may provide both of these requirements in vivo for several periodontal pathogens but most notably for the red complex organism Tannerella forsythia. Several other periodontal pathogens also possess sialic acid scavenging enzymes – sialidases, which can also expose adhesive epitopes, but might also act as adhesins in their own right. In addition, recent experimental work coupled with the release of several genome sequences has revealed that periodontal bacteria have a range of sialic acid uptake and utilization systems while others may also use sialic acid as a cloaking device on their surface to mimic host and avoid immune recognition. This review will focus on these systems in a range of periodontal bacteria with a focus on Ta. forsythia.