Variations of Streptococci With a Note on Hemolysin Production
Year: 1928
Type: article
Abstract: 1910), Jungman (1921), and others in which hemolytic strepto-cocci (S. hemolyticus) have changed either spontaneously, or as a result of certain definite cultural procedures, into green producing streptococci (S. viridans). It is the object of this paper to show how error may arise from failure to recognize the true nature of a strain of streptococcus at the start of such investigations. Strains of Streptococcus viridans are frequently found which, in rabbit-blood agar, pour plates, incubated aerobically for twenty-four to forty-eight hours, at 37°C., produce zones of hemolysis 2 to 4 mm. in width about the deep colonies. A photograph of such a blood agar culture is reproduced in figure 1. Such a strain of streptococci might be reported as Streptococcus hemolyti-cus. Certainly, if one regards as S. hemolyticus any strain show-ing a wide zone of hemolysis in blood agar pour plates (and it appears likely that this has been done in the past) then this strain would be regarded as of that type. Production of a zone of hemol-ysis of any width, however, is not the differential point. Streptococci are of three main types as regards action in 5 per
Source: Journal of Bacteriology
Authors: M. Frobisher, E. R. Denny
Institutions: Johns Hopkins University, Johns Hopkins Hospital
Language: English
Subfield: Infectious Diseases
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W110488634