RESUMO
Isolation of the smooth (Sm) morphotype of Peptostreptococcus micros, a suspected oral pathogen, is sometimes accompanied by isolation of a rough (Rg) morphotype of P. micros. The Rg type readily changes to a Sm-like variant (RgSm) in broth culture. Sm and Rg isolates and RgSm variants were compared to determine whether these three types are the result of phase variation. The RgSm variants resembled the Sm morphotype in colony morphology; furthermore, the Sm type and the RgSm type did not have the fibrillar surface structures characteristic of the Rg type, and the Sm and RgSm types were more hydrophobic than the Rg type. However, when we compared the sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns of whole-cell proteins, serotyping data, pyrolysis mass spectrometry data, 16S ribosomal DNA sequences, and hemolytic activities, the RgSm variants and the Rg isolates were very similar and were clearly distinct from the Sm isolates. These results suggest that the Rg and RgSm types form a cluster distinct from the Sm type and thus provide evidence that P. micros can be differentiated into two groups, one consisting of the Sm type and the other consisting of the Rg and RgSm types.
Assuntos
Peptostreptococcus/classificação , Sequência de Bases , Primers do DNA/genética , DNA Bacteriano/genética , DNA Ribossômico/genética , Humanos , Espectrometria de Massas , Dados de Sequência Molecular , Boca/microbiologia , Peptostreptococcus/genética , Peptostreptococcus/isolamento & purificação , Fenótipo , Filogenia , RNA Bacteriano/genética , RNA Ribossômico 16S/genética , SorotipagemRESUMO
Two selective media, malachite green-bacitracin (MGB) agar and tryptic soy-serum-bacitracin-vancomycin (TSBV) agar, were compared for the isolation of Actinobacillus actinomycetemcomitans. The highest recovery was found on TSBV agar plates cultured in air-5% CO2 both for plaque samples from periodontal pockets and for pure cultures.
