The classification of coliform bacteria

Abstract

A study of the biological characters of 1636 cultures of coliform bacteria, isolated from milk and bovine faeces, shows that the coliform group consists of a large number of different types. These types are so closely interlinked in characters and in relations to environment as to justify their inclusion in one genus. Nevertheless, to facilitate the identification of types, the group may be subdivided into subgroups, the Voges-Proskauer, Koser, inositol and indole reactions being reliable and outstanding criteria for this purpose. These characters show almost perfect correlations with various other characters. Thus Voges-Proskauer-negative types have a low CO2to H2ratio and are methyl-red-positive; Voges-Proskauer-positive types have a high CO2to H2ratio, are methyl-red-negative and Koser-positive. Koser-negative types are not highly resistant to brilliant green, are non-capsulated, do not form thick mucoid colonies and are Voges-Proskauer-negative, inositol-negative and indole-positive. Koser-positive types are highly resistant to brilliant green, and with the exception of group 2 and certain members of group 3, are frequently encapsulated and form thick, mucoid colonies. Non-inositol-fermenters are as a rule motile and adonitol-negative. Inositol-fermenters are Koser-positive, adonitol-positive, sucrose-positive and raffinose-positive; are frequently encapsulated and form thick, mucoid colonies; and as a rule are non-motile. Indole-negative types are Koser-positive, while indole-positive types are generally Koser-positive or negative according to whether the inositol reactions are positive or negative.

Fermentation of polysaccharides by Klebsielleae and other facultative bacilli

“…These results gave 68 and 94% positive at 7 and 21 days, respectively, for K. oxytoca and 5 and 14% positive at 7 and 21 days, respectively, for K. pneumoniae. These results are simnilar to those of Malcolm (83% of K. oxytoca and 15% of K. pneumoniae positive at 14 days [27] and of Lautrop (76% of K. oxytoca and none of K. pneumoniae at 30 days [24]). Malcolm (27) showed that 19% of his E. aerogenes strains and 6% of his E. cloacae strains were positive at 14 days.…”

The differentiation of Enterobacteriaceae infecting the urinary tract: A study in male paraplegics

“…MacConkey (quoted by Malcolm, 1938) used the fermentation of inositol and adonitol to distinguish 'B. coli' from 'B.…”

The Occurrence of Coli‐aerogenes Organisms on Plants

“…No. of specimens with coli-aerogenes organisms The grouping of the coli-aerogenes organisms isolated from vegetation and soil From the 407 positive specimens of vegetation and soil, 438 cultures were isolated and classified according to their V-P, citrate, inositol and indole reactions (see Malcolm, 1938) as follows: Exherichia coli (---+); intermediate (-+ **); Aerobacter cloacae (++--) and Aerobacter aerogenes (+++&I).…”

“…The inositol reaction has been used because the inositol-fermenters were not only citrate positive, but were frequently encapsulated, formed thick mucoid colonies and were as a rule non-motile. Species differentiation in Aerobacter has therefore been based on the fermentation of inositol (Malcolm, 1938) and not on gas production from glycerol, as in Bergey's Manual. The distribution of the various organisms according to their origin is given in Table 3, which shows that with the exception of grazed pasture the different kinds of vegetation and grain had generally similar coli-aerogenes floras.…”

“…For this reason they have been referred to frequently as 'non-faecal' or 'vegetation' types of coli-aerogenes bacteria. Aerobacter types, however, are apparently capable of a commensal existence as they have been found to be present normally in the human and animal intestine and in faeces (Ford, 1927;Cruickshank & Cruickshank, 1931 ;Hay, 1932 ; Bardsley, 1926;Sherman, 1935;Malcolm, 1938), but in smaller numbers thin Escherichia so that enrichment methods may be necessary for their isolation.…”