An Ecological Study of the Coliform Bacteria

Abstract
6577 strains of coliform organisms from milk, water, soil, grains, barn dust and cow hides, and human and bovine feces were typed by means of the IMViC (indol, methyl-red, Voges-Proskauer, citrate, and cellobiose) reactions. Statistical analysis of the results indicated that Aerobacter and intermediate strains are normal inhabitants of non-fecal environments, and Escherichia are normal in feces. Occurrence otherwise was considered adventitious. Studies of strains varying in IMViC reactions indicated that indol production, by virtue of its greater stability, is preferable to citrate utilization for use in conjunction with the Voges-Proskauer reaction in determination of the sections of the coliform group. The advisability of speciation within the genus Aerobacter, and the significance of aberrant lactose fermentation are discussed.