Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)




Organisms referred to as "fecal streptococci" or "enterococci" have been studied as possible indicators of pathogenic bacteria of fecal origin since their· discovery. In Bergey's Manual of Determinative Bacteriology (1957), the "enterococci" are classified as Streptococcus faecalis, Streptococcus faecalis var. liquefaciens, Streptococcus faecalis var. zyrnogenes and Streptococcus durans. Streptococcus bovis and Streptococcus equinus do not meet all the criteria of the enterococcus group. However, they are found in great numbers in certain fecal material. These organisms, and the”enterococci" are collectively referred to as "fecal streptococci." The unavailability of satisfactory methods and of selective media has prevented the acceptance of these organisms for indicative purposes. Recently, media which give satisfactory results and methods which rapidly produce these results have been developed. Now, many have become interested in this area, and are suggesting reevaluation of this group as indicators. Standard Methods (APHA, 1965) has long utilized the Most Probable Number (MPN) multiple tube method to statistically determine the number of coliform organisms in a sample. These coliform organisms have found common usage as indicators of pathogens in the routine analysis of water for potability. The fecal coliform test, also described in Standard Methods, demonstrates the presence of an indicator known to be from the intestinal tract of warm-blooded animals. The enumeration of this organism is also an MPN procedure. The fecal streptococci could well become established as indicators concerned with detecting the source of contamination. These organisms might best be utilized as a supplementary test rather than a substitute for the other tests currently being used. In Great Britain, fecal streptococci are used routinely in the analysis of water for drinking purposes. The development of the membrane filter has provided this phase of bacteriology with an invaluable tool which allows the rapid, numerical quantification of organisms from variable amounts of water. It provides surface colonies as well as a differential test on a medium containing a reducible indicator. In this study, the distribution of the fecal streptococci in three types of surface water was studied using media currently recommended for biochemical characterization of isolates and the membrane filter technique. The differentiation of certain members of the fecal streptococci on the basis of colonial appearance on membrane filters was also studied, with the hope that the results of these studies would help investigators to estimate the sources of pollution by distinguishing between human and farm animal wastes.

Library of Congress Subject Headings

Water -- South Dakota




South Dakota State University