Atypical (slow) Lactose FermentingB. coli

Abstract

This paper deals with the culture characteristics of atypical colon bacilli frequently encountered in feces of cows with intestinal disorders. In laetose-agar plate cultures the organisms fail to change the reaction and for this reason may be mistaken for paratyphoid bacilli. It was established that in broth containing lactose there is a phase in which carbohydrate is utilized without changing the reaction, followed by a phase in which acid is slowly produced. Such organisms are not regarded as true mutants of Bacillus coli, since it is shown that no new qualitative differences had developed but that apparent culture and antigenic differences could be explained on quantitative grounds.