- Volume 28, Issue 4, 1978

Spirosomaceae fam. nov. is proposed for the curved, coil- and filament-forming, pigmented, strictly aerobic organisms in the genera Spirosoma Migula 1894, Flectobacillus Larkin et al. 1977, and Runella Larkin and Williams 1978. The type genus is Spirosoma.

Due to the close systematic relationships within the tribe Escherichieae, definition of the taxon Shigella should be based primarily on the potential enteropathogenicity of the dysentery types. Immobile and anaerogenic dysentery bacilli possessing biochemical activities exceeding the established Shigella norm could be included in Shigella subgroup D, to which should be given the name S. metadysenteriae to avoid misunderstandings resulting from lipopolysaccharide phase designations I and II of S. sonnei. S. sonnei, serotypes 792 and serotype 147, and S. guanabara are proposed to be listed as serotypes 1 to 4 of S. metadysenteriae. Regularly aerogenic and/or motile dysentery types of the tribe Escherichieae—E. coli O124, O136, O143, O144, and O152—could be placed for the present into a provisional taxon Escherichia dysenteriae.

The guanine-plus-cytosine (G+C) contents of the deoxyribonucleic acids (DNA) from ureaplasmas (T-mycoplasmas) isolated from several animal species were determined. The values obtained indicate that the G+C content of ureaplasmas is within a range from 26.9 to 31.6 mol%. The distinctness of the DNA G+C content of bovine isolates from that of Ureaplasma urealyticum (the human isolates) is confirmed. The values found for the DNA from canine and feline strains did not distinguish them from U. urealyticum. The caprine and ovine strains have DNA G+C contents similar to but slightly higher than those of the bovine strains. Although the strain isolated from a marmoset has a G+C content that is within the range observed for bovine isolates, the strain isolated from a squirrel monkey has a G+C content that falls between the ranges observed for human and bovine isolates. The results support the suggestion that more than a single species or subspecies exists within the genus Ureaplasma, but more evidence is needed before proposals for new taxa can be made.

On the basis of a study of the effect of trimethoprim on the growth of 131 rapidly growing mycobacteria identified at the species level, it was found that two of the stains were possibly misidentified. This suspicion was confirmed by checking the salient phenotypic characters of the strains. It was found that strain TMC 1523 is not a strain of Mycobacterium phlei but of M. smegmatis and that strain SN40, previously identified as a member of M. smegmatis, is a strain of M. fortuitum.

A definition of a microbial species, slowly evolved during years of work with many strains, is presented and explained.

The status of the genus Torulopsis Berlese is discussed. An amendment of the diagnosis of the genus Candida Berkhout is proposed to allow for nonhyphal species. In accordance with the amended description, the species currently classified in Torulopsis are transferred to the genus Candida.

Serotypes B and C of Cryptococcus neoformans are described as a separate species, C. bacillisporus sp. nov. C. bacillisporus could be distinguished from C. neoformans by creatinine metabolism. Serotype B and C isolates utilized creatinine much more readily than A and D, resulting in increased ammonia production and alkaline pH. Based on these findings, a creatinine-dextrose-bromothymol blue agar medium (pH 5.7) was developed as a single-step culture method for separation of the two species. Isolates of C. neoformans can be distinguished from C. bacillisporus with 97% accuracy by 48 h.