Coliform Intermediates in Human Feces

Abstract

Although foundation for the recognition of coliform inter-mediates was laid by Brown (1921), he did not utilize his findings for their demonstration. Brown was interested in mediums con-taining citrated blood and attempted to determine the effect citrate might have on the growth of organisms likely to be encoun-tered in blood culture work. Koser (1923, 1924a, b, c, d, 1926) applied to coliform bacteria (Breed and Norton, 1937) tests involving utilization of organic acids and their salts. He found that Bacterium coli from feces could not utilize citrate as a sole carbon source in contrast to Bacterium aerogenes. Koser found, particularly in soil and water, organisms classed as coli by the criteria then used but which utilized citrate-carbon and, in this respect, resembled B. aerogenes. In 1924 Koser applied the term "intermediate " to these forms. Recognition of such intermediate forms should make possible a better theoretical understanding of the entire coliform group, than which few in bacteriology are more complex or confused. Any fundamental advance, such as the intermediate concept, should enable sanitary science to define more accurately such terms as "pollution " and "potability " and to answer numerous practical questions posed in this field in recent years. Parr (1936a, b, 1937) defined intermediates as coliform or-ganisms "which have one or more coli characters and one or more of those attributed to aerogenes, and some 'intermediates, ' includ-ing the typical fecal form, produce hydrogen sulphide. " This definition permits the inclusion as intermediates of organisms