Saliva From Subjects Harboring Actinobacillus actinomycetemcomitans Kills Streptococcus mutans In Vitro

Abstract

Aa-positive subjects had a salivary factor that significantly reduced survival of Sm, which may help to explain the fact that this group typically has minimal proximal decay.

A Lactotransferrin Single Nucleotide Polymorphism Demonstrates Biological Activity That Can Reduce Susceptibility to Caries

“…Two subjects were selected for screening for suspected anti-S. mutans activity, and two were selected as inactive controls. Based on prior evidence, two subjects susceptible to localized aggressive periodontitis (LAP) with minimal proximal decay were selected because previous research indicated that they might possess saliva with anti-S. mutans activity (13). In addition, two subjects who were caries susceptible and harbored elevated levels of S. mutans were selected as screening controls, since previous research suggested that they were unlikely to possess the anti-S. mutans factor in their saliva (13).…”

“…Based on prior evidence, two subjects susceptible to localized aggressive periodontitis (LAP) with minimal proximal decay were selected because previous research indicated that they might possess saliva with anti-S. mutans activity (13). In addition, two subjects who were caries susceptible and harbored elevated levels of S. mutans were selected as screening controls, since previous research suggested that they were unlikely to possess the anti-S. mutans factor in their saliva (13). All subjects selected for screening were medically healthy, willing to be subjected to an oral examination, and willing to contribute plaque and saliva for testing for anti-S. mutans activity.…”

“…In this manner, S. mutans already existing in the subject's saliva would not interfere with our ability to assess anti-S. mutans activity in whole saliva, because native S. mutans could not grow on rifampin-containing selective medium. A rifampin-resistant strain of S. mutans ATCC 33402 was created for testing by growing the parent strain in mitis salivarius (MS) agar containing 35 g/ml rif (13). Resistant colonies that grew on the agar were restreaked on MS agar containing 70 g/ml rif to obtain S. mutans 33402 rif, which was prepared for testing of salivary activity against S. mutans.…”

“…To identify saliva that had anti-S. mutans activity, we developed a disk diffusion assay as described previously (13). Briefly, 200 l of clarified saliva, at a protein concentration of 40 to 50 g/ml, was applied to the surface of a sterile 22-by 22-mm filter paper disk.…”

“…Briefly, 200 l of clarified saliva, at a protein concentration of 40 to 50 g/ml, was applied to the surface of a sterile 22-by 22-mm filter paper disk. The disk was placed in an incubator set at 37°C for 1 h so that the saliva was fully incorporated into the dried disk (13). For testing, S. mutans strain 33402 rif, obtained from a frozen stock, was grown under aerobic conditions overnight at 37°C in Trypticase soy broth (TSB) containing 70 g/ml rif.…”