The Sanitary Significance of Pectin-Fermenting, Lactose-Fermenting, Gram-Negative, Non-Spore-Forming Bacteria in Water

Abstract

Pectin-fermenting strains were detected by the production of acid in a synthetic medium to which alcohol-sterilized pectin had been added aseptically. No visible fermentation occurred in a similarly prepd. extract broth medium. Of 507 strains of coliform organisms which were isolated on eosin methylene-blue agar from the feces of 56 persons, 68 from the feces of 3 horses and 118 from the feces of 6 fowls, none fermented pectin. Of 92 strains from the feces of 7 cows, 3 fermented pectin; of 44 from the feces of 3 mules, 7 fermented pectin, and of 115 from the feces of 7 dogs, 38 fermented pectin. Of 259 strains which were isolated from water following enrichment in Standard Methods lactose broth or in pectin enrichment broth, 71 fermented pectin. 28 strains possessed typical Aerobacter aerogenes characteristics, 32 possessed the characteristics of intermediate coliform organisms and 4, all of which were isolated from water, possessed typical Escherichia coli characteristics. Since relatively more pectin-fermenting coliform organisms were found in water than in the feces of animals, some of them at least were probably not of fecal origin and might even have been members of the genus Erwinia or non-pectin-fermenting strains of Serratia.