Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 1929 Sep 30;50(4):463-9.
doi: 10.1084/jem.50.4.463.

DIFFERENTIATION OF HEMOLYTIC STREPTOCOCCI OF HUMAN AND OF DAIRY ORIGIN BY METHYLENE BLUE TOLERANCE AND FINAL ACIDITY

R C Avery  1
Affiliations

DIFFERENTIATION OF HEMOLYTIC STREPTOCOCCI OF HUMAN AND OF DAIRY ORIGIN BY METHYLENE BLUE TOLERANCE AND FINAL ACIDITY

R C Avery. J Exp Med. .

Abstract

A grouping of 138 strains of hemolytic streptococci based on differences in dye-sensitiveness and in final hydrogen-ion concentration of cultures is presented. Three groups are distinguished; (1) human parasitic strains, defined by a final pH range of 5.2 to 5.0 and by failure to reduce methylene blue (1:5000) in milk, (2) bovine strains parasitic in the udder, characterized by a final pH range of 4.5 to 4.2 and by failure to reduce methylene blue (1:5000) in milk, (3) saprophytic strains, characterized by a final pH range of 4.5 to 4.2 and by ability to reduce methylene blue. Methylene blue was bactericidal for the strains of hemolytic streptococci that fail to reduce it, but neither bacteriostatic nor bactericidal for the strains that caused its reduction.

PubMed Disclaimer

References

    1. J Bacteriol. 1918 Mar;3(2):153-74 - PubMed
    1. J Exp Med. 1919 Jan 31;29(2):215-34 - PubMed
    1. J Exp Med. 1921 Jan 1;33(1):13-24 - PubMed