Exploring the oral bacterial flora: current status and future directions

Abstract

Oral Diseases (2010) 16, 136–145 Objective: The oral cavity forms an indispensable part of the human microbiome, for its unique and diverse microflora distributed within various niches. While majority of these organisms exhibit commensalism, shifts in bacterial community dynamics cause pathological changes within oral cavity and distant sites. The aim of this review was to appraise the current and emerging methods of detecting bacteria of the oral cavity paying particular attention to the cultivation independent methods. Design: Literature pertaining to cultivation based and cultivation independent methods of oral bacterial identification was reviewed. Methods: The specific advantages and disadvantages of cultivation based, microscopic, immunological and metagenomic identification methods were appraised. Results: Because of their fastidious and exacting growth requirements, cultivation based studies grossly underestimate the extent of bacterial diversity in these polymicrobial infections. Culture independent methods deemed more sensitive in identifying difficult to culture and novel bacterial species. Conclusion: Apart from characterizing potentially novel bacterial species, the nucleic acid sequence data analyzed using various bioinformatics protocols have revealed that there are in excess of 700 bacterial species inhabiting the mouth. Moreover, the latest pyrosequencing based methods have further broadened the extent of bacterial diversity in oral niches.

Exploring Bacterial Diversity of Endodontic Microbiota by Cloning and Sequencing 16S rRNA

“…The assessment of the human microbioma by metagenomic approaches revealed that these techniques are sensitive and specific (6,11) to evaluate the bacterial diversity of root canal infections (10,(12)(13)(14)(15). These studies have shown that the prevalence of yet non-cultivable bacteria remarks over 50% of the microbiota in primary endodontic infections (10,14), in persistent periradicular lesions (15), or in mixed endodontic infections (16).…”

“…Most data on the endodontic microbiota were obtained by culture approaches (3)(4)(5), but culture-dependent methods grossly underestimate the extent of bacterial diversity in polymicrobial infections (6). Furthermore, phenotypic profiles variations and methodological bias also limit the conclusions drawn from culture studies (7).…”

Protective Mechanisms of Respiratory Tract Streptococci against Streptococcus pyogenes Biofilm Formation and Epithelial Cell Infection

“…Therefore, the skin and the upper respiratory tract are the primary GAS contact sites on new human hosts (18). Both anatomic sites are physiologically inhabited by several dozen (skin) to several hundred (respiratory tract) different bacterial species (19)(20)(21)(22)(23), of which the majority can only be demonstrated by molecular techniques (24,25). Many of these species have probiotic potential that could be exerted by biofilm formation on anatomical sites serving as targets for pathogenic bacteria.…”

Bacterial Leakage Along the Implant-Abutment Interface

“…However, an inherent limitation of microbiological cultures is that the difficulties to identify strict anaerobes, frequently associated with periodontal and peri-implant diseases, as well as fastidious species Roças et al, 2010). It is estimated that 50% of the oral microbiota is not cultured by conventional methods and several of these species are directly related to infectious processes in the oral cavity (Arank et al, 1969;Paster et al, 2001;Parahitiyawa et al, 2010). Furthermore, non-viable cells, still able to produce aggressive compounds against peri-implant tissues are not detected by culture methods.…”