Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)




Micrococcus pyogenes var. aureus (Rosenbach) Zoph has been known to man for some time, for it was back in 1878 that Koch noted the presence of micrococci in pus from wounds. in all probability these organisms were Micrococcus pyogenes var. aureus or their very closely related type species Micrococcus pyogenes var. albus. It is very interesting to note relatively small amount of attention paid to this genus after the early taxonomic work was completed, and it was for this reason that this study was undertaken. In the fall of 1953 cases of tonsillitis, laryngitis, or sore throats were quite prevalent on the campus of South Dakota State College. The Health Service on the campus co-operated by providing fresh material. This material was obtained by swabbing the patient’s (student’s) throat, nasopharynx, and tonsillar crypts. The swabs were prepared by twisting a small piece of absorbent cotton on the end of the six inch wood applicator. Two of these swabs were placed in a six inch test tube and the tube was then cotton plugged and autoclaved. One swab was used for the patient’s throat and the other for the nasopharynx. In the laboratory each swab was streaked on Nutrient, Champan Stone, and Blood Agar plates (6) and incubated at 37 degrees C for 12 to 18 hours. Immediately after streaking the plates, direct slides were prepared by rolling the swab on a clean slide. These were then gram stained and examined under oil immersion. Direct microscopic examination revealed that the predominating organism was a gram positive micrococcus .8 to 1.0 microns in diameter, appearing singly and in small clumps. Other organisms present to a lesser degree included short-chain streptococci and diphtheroids. After 12 to 18 hours of incubation the plates were examined, and it was easily discernible that the predominating organisms were micrococci. These micrococci were actively hemolytic, producing a clear, well defined zone of beta hemolysis on the blood agar plate. They were also most abundant on the nutrient agar plate and here grew with a somewhat yellowish to golden sheen. Since Champan Stone is a selective medium for micrococci, they grew well, exhibiting a definite golden pigament. Therefore, from the isolation and growth characteristic studies, it was concluded that in all probability this organism was responsible for the small endemic outbreak of “sore throat” on this campus. Appropriate biochemical tests and taxonomic procedures were applied to this organism to properly classify it as Micrococcus pyogenes var. aureus (Rosenbach) Zoph (2). The cultures obtained from seven patients were not mixed but were carried on separate nutrient agar and Chapman Stone slants and in Kracke Blood Culture Medium (6). The organism used for subsequent investigational purposes was the author’s own particular isolate. Since all seven strains isolated had very similar characteristics, no particular reason or provocation can be given for picking this one from the rest, outside of a probable hypochondrial tendency on the part of the investigator. This also aided in making the work a little more stimulating.

Library of Congress Subject Headings

Pathogenic microorganisms


Includes bibliographic references



Number of Pages



South Dakota State University


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