Taxonomy of the Family Enterobacteriaceae

Abstract

Current knowledge of the organisms commonly grouped in the family Enterobacteriaceae is not reflected adequately in taxonomic systems. Consequently, certain workers propose to ignore one or more generic distinctions of practical value while others magnify differences between strains to a significance that results in an absurdly complex multiplicity of species. Applied bacteriology suffers from the ensuing confusion. Based upon recent studies, including those of the authors, a revision of the family is proposed along lines which will mitigate this confusion and will direct attention to studies needed to produce results of taxonomic significance. Tribes are eliminated and genera are defined primarily upon chromogenesis, avidity for lactose and ability to hydrolyze urea with special emphasis upon other biochemical characteristics and anti-genic structure where required. 8 genera are suggested including Ser-ratia, Erwinia, Proteus, Salmonella and Shigella with emended circumscriptions as well as 3 genera of coliform and allied organisms as follows: COLOBACTRUM, rapid producers of gas from lactose; PARACOLOBACTRUM, consistently slow gas producers; and PROSHIGELLA, forms anaerogenic in all carbohydrates. Speciation within the genera is accomplished by broad criteria with certain concessions to convention. Stress is laid upon the use of varietal designations to meet practical needs. A uniform varietal terminology is discussed.