Development of a selective medium for detection and enumeration of Actinomyces viscosus and Actinomyces naeslundii in dental plaque

Abstract

A selective medium (CFAT) was developed for the detection and enumeration of Actinomyces viscosus and Actinomyces naeslundii in dental plaque. Neutral acriflavin and potassium tellurite were used in combination with the known selective agents cadmium and fluoride to eliminate most of the competing plaque flora. Composition of CFAT per liter was as follows: Trypticase soy broth (BBL Microbiology Systems), 30 g; glucose, 5 g; agar, 15 g; cadmium sulfate, 13 mg; sodium fluoride, 85 mg; neutral acriflavin, 1.20 mg; potassium tellurite, 2.50 mg; basic fuchsin, 1.25 mg; defibrinated sheep blood, 50 ml. A. viscosus reference strains of human origin grew on CFAT without reduction in numbers under an atmosphere of 90% air-10% CO2. Animal strains of A. viscosus were inhibited at the level of cadmium in CFAT. Two of six A. naeslundii strains did not grow on CFAT. Improved recovery of A. viscosus and A. naeslundii from dental plaque occurred on CFAT, as compared with two other selective media which contained either cadmium sulfate or sodium fluoride, respectively, as selective agents. CFAT was more selective with regard to much of the extraneous gram-positive flora. Bacterionemia, Neisseria, yeasts, and streptococci were virtually eliminated.

Bacteria in supragingival plaque samples can be killed by low‐power laser light in the presence of a photosensitizer

“…Each series of bacterial suspensions obtained as described above was then plated, in duplicate, onto the following media : for Actinomyces spp. (Zylber and Jordan 1982).…”

Changes in subgingival microbiota during puberty A 4-year longitudinal study

“…This set of tests allowed the presumptive identification of some predominant bacteria of the subgingival plaque (Qadri & Johnson 1981, Laughon et al 1982a, b, Gusberti & Syed 1984, see Table 1. In addition, each plaque sample was plated onto CFAT (Zylber & Jordan 1982); Actinomyces naeslundii and A. viscosus were identified based on colony morphology and catalase activity. ETSA supplemented with 0.05% Kanamycin sulfate (Loesche et al 1971) was used Table 2.…”

Salivary conditions and cariogenic microorganisms in 55, 65, and 75‐year‐old Swedish individuals

“…Aliqtiots of 25 |il of the appropriate dilutions were placed in duplicate on mitis-salivarius-bacitracin (MSB) agar (19) to grovv mutans streptococci atid in Rogosa SL agar to grow lactobacilli. Duplicates of the plaque samples were also placed on the selective medium CEAT (20) to grow A. iiiscosus and A. naeslundii and on trypticase soy agar supplemented with 5% horse blood for the total viable count. The MSB and blood agar plates were incubated for 2 and 7 days respectively at 37°G iti an atmosphere of 95% N, and 5% COj.…”