Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Biology and Microbiology


The importance of the fecal streptococci as indicators of water pollution has come under increasing scrutiny. in the past decade. This has been due in part to improved methods of detection of fecal streptococci. Also, the fecal coliform and total coliform tests and· their significance have been questioned. The fecal streptococci may furnish a more reliable means of identifying sources of pollution. The fecal streptococci are those gram-positive cocci which occur in the intestinal tract of man and animals. The Sherman criteria for identification of the fecal streptococci are used in Bergey's Manual of Determinative Bacteriology to differentiate the viridans and enterococci from the other streptococci. The enterococcus group includes Streptococcus faecalis, S- faecium, and S- faecium var. durans. The viridans group includes two species of interest in this study, Streptococcus bovis and S. equinus . All of the above mentioned species of Streptococcus contain Lancefield's group D antigen and occur in nature in the intestinal tract of man and animals. Like the fecal coliforms, the fecal streptococci are indicators of pollution in water. The characteristics of an indicator include: (1) the organism must be found in feces and sewage, (2) the organism is found in polluted water, (3) the organism is not found in pure water sites away from man and animals, and (4) the organism does not multiply outside the host in water or soil. The usefulness of the fecal streptococci does not end here, however. The fecal streptococci can be used to identify either human or an animal source of pollution. This is illustrated by the fact that S. faecalis strains are found predominantly in the normal flora of the human intestinal tract. · In contrast, S.equinus and S. bovis are found predominantly in the caecum of horses and the rumen of cattle, respectively. Although S. bovis has been isolated, identified, and reported by various authors, an improved method for isolating this particular species was not devised until Koupal modified existing methods of isolating fecal streptococci. Koupal's method of isolating S. bovis was relatively crude, in that it requires many steps and a refined substrate was never utilized. It is the purpose of this investigation to develop a new method of isolating S. bovis and to evaluate the usability of these improvements in tracing ruminant water pollution. These improvements would include a rapid method for detection and enumeration of S. bovis for quantitation of this organism from surface waters as an indicator of bovine fecal pollution.

Library of Congress Subject Headings


Water -- Pollution


South Dakota State University Theses



Number of Pages



South Dakota State University