Eijkman Relationships of the Coliform and Related Bacteria

Abstract

Ability of several genera of the Enterobacteriaceae to grow, produce acid, or to produce gas in the modified Eijkman medium at 45.5[degree]C was detd. The more primitive genera, Serratia and Erwinia, were frequently killed by a temp. of 45.5[degree]C. 3059 normal coliform organisms, isolated from various sources, were tested at 45.5[degree]C in Eijkman lactose broth. The majority of Aerobacter cultures, with the exception of indole-producing types, showed growth, and of 894 cultures only 1.9% produced gas. Of 882 intermediate cultures 0.3% produced gas in contrast to 97.3% of 1283 Escherichia cultures, thus indicating a much closer relationship of the intermediates to Aerobacter. In Eijkman dextrose broth at 45.5[degree]C Pr. mirabilis generally produced acid or gas whereas Proteus vulgaris and P. morganii generally failed to do so. Salmonella strains usually produced acid and some produced gas from broth inoculations, and E. typhosa produced acid from agar-slant inoculations. In the genus Shigella, alkalescens and sonnei produced acid readily at 45.5[degree]C while the paradysenteriae strains generally failed to grow. A simplified grouping of the coliform organisms is proposed correlating their IMVIC reactions, Eijkman reactions, and probable origin. This grouping is proposed for convenience and carries no taxonomic recommendations.