Strains of streptococci originally isolated from the dental plaque of monkeys () and designated as serotype h were compared with the other species of the mutans streptococcus group. Despite the close resemblance noted previously between these strains and , closer examination revealed several important differences. Strains of serotype h ferment mannitol but not sorbitol, melibiose, inulin, or raffinose, do not produce hydrogen peroxide, and are unable to grow in the presence of bacitracin at 2 units per ml. They exhibit a distinct polypeptide pattern by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and possess several antigens absent from as revealed by Western blotting (immunoblotting). Virtually identical polar lipid patterns were observed by two-dimensional thin-layer chromatography for both serotype h strains and , although on the basis of long-chain fatty acid analysis by capillary gas-liquid chromatography, the former could be distinguished by the presence of a peak tentatively identified as cyclopropane acid (-9, 10-methyleneoctadecanoate (ΔC 19:0). Deoxyribonucleic acid (DNA)-DNA hybridization studies by both the S1 nuclease and renaturation rate methods showed that serotype h strains differ from , and . On the basis of these data, we believe that serotype h strains represent a distinct species for which the name is proposed. The DNA base composition is 41 to 42 moles percent guanine plus cytosine. The type strain is strain MFe28 (NCTC 11391), which is cariogenic in monoassociated germfree rats.


Article metrics loading...

Loading full text...

Full text loading...


Most cited this month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error