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H A Linke

Publications and source records attributed to H A Linke.

3 recordsLinked to original sources
PubMed1977

New method for the isolation of Streptococcus mutans and its differentiation from other oral streptococci.

A new, improved agar medium for the isolation of Streptococcus mutans, the etiological agent of dental caries, was developed. In contrast to mitis-salivarius agar, this medium not only recovers a greater number of S. mutans strains from most oral specimens but, because of its mannitol and sorbitol content, it also facilitates the differentiation of S. mutans from other oral streptococci, e.g., S. salivarius, S. mitis, and S. sanguis, which do not grow or produce scanty growth only after 10 days of incubation. The medium is easy to prepare because of its simple and unique composition, is characterized by the presence of an acid indicator, and can be utilized under aerobic and anaerobic conditions as well. The medium cannot be used to distinguish among the eight serotypes, a to g and SL-1, of S. mutans. Mannitol-utilizing bacteria such as streptococci (e.g., S. faecalis) and other microorganisms (e.g., Staphylococcus aureus) are able to grow on this medium and can be distinguished from S. mutans by their unique colony morphology.

Aerobiosis↗
PubMedDate not supplied

Physiological effects of sucrose substitutes and artificial sweeteners on growth pattern and acid production of glucose-grown Streptococcus mutans strains in vitro.

The synergistic effects of four sucrose substitutes, polysorbate and five artificial sweeteners were studied in vitro on growth pattern and acid production of seven glucose-grown Streptococcus mutans strains, representing the five serological groups after Bratthall. Four distinct growth patterns during glucose fermentation were observed: high rate of growth with low acid production, moderate growth rate with moderate acid production, moderate growth rate with high acid production, and slow rate of growth with moderate acid production. Depending on the strain used, the final OD at 546 nm ranged from 0.55 to 0.99 and the final pH of the medium varied between 4.65 and 4.15. While added sucrose substitutes, with exceptions, usually enhanced growth rate, most artificial sweeteners suppressed or, at higher concentrations, even inhibited growth of S. mutans; addition of polysorbate to the medium always increased growth rate of S. mutans significantly. The presence of sucrose substitutes during glucose fermentation had no effect on final pH of the medium, but addition of artificial sweeteners, especially sodium saccharin, elevated final pH up to 1.8 units. The observed physiological patterns and differences within the several strains of S. mutans during glucose fermentation in vitro do not necessarily relate to the five serological groups of the species.

Fructose↗