Comparisons of subgingival microbial profiles of refractory periodontitis, severe periodontitis, and periodontal health using the human oral microbe identification microarray.

Background: This study compared the subgingival microbiota of subjects with refractory periodontitis (RP) to those in subjects with treatable periodontitis (GRs = good responders) or periodontal health (PH) using the Human Oral Microbe Identification Microarray (HOMIM).

Methods: At baseline, subgingival plaque samples were taken from 47 subjects with periodontitis and 20 individuals with PH and analyzed for the presence of 300 species by HOMIM. The subjects with periodontitis were classified as having RP (n = 17) based on mean attachment loss (AL) and/or more than three sites with AL >or=2.

Bacterial diversity in necrotizing ulcerative periodontitis in HIV-positive subjects.

Background: Necrotizing ulcerative periodontitis (NUP) is a painful and potentially debilitating affliction that affects about 2% to 6% of HIV-positive subjects. NUP may be caused by specific microorganisms that are presently unknown or by microbial species not usually thought to cause periodontal infections. The purpose of this study was to define the bacterial species associated with NUP in HIV-positive patients.

Two paralogous families of a two-gene subtilisin operon are widely distributed in oral treponemes.

Certain oral treponemes express a highly proteolytic phenotype and have been associated with periodontal diseases. The periodontal pathogen Treponema denticola produces dentilisin, a serine protease of the subtilisin family. The two-gene operon prcA-prtP is required for expression of active dentilisin (PrtP), a putative lipoprotein attached to the treponeme's outer membrane or sheath.

Molecular analysis of bacterial species associated with childhood caries.

Although substantial epidemiologic evidence links Streptococcus mutans to caries, the pathobiology of caries may involve more complex communities of bacterial species. Molecular methods for bacterial identification and enumeration now make it possible to more precisely study the microbiota associated with dental caries. The purpose of this study was to compare the bacteria found in early childhood caries (ECC) to those found in caries-free children by using molecular identification methods.