Genetic and serologic relatedness between Mycoplasma fermentans strains and a mycoplasma recently identified in tissues of AIDS and non-AIDS patients.

A mycoplasma previously identified in the tissues of both AIDS and non-AIDS patients dying of an acute fatal disease was earlier shown to share some biologic and genetic properties with a strain of Mycoplasma fermentans, an organism occurring infrequently in the human lower urogenital tract. More extensive genetic and serologic comparisons using DNA/DNA hybridization, DNA base composition (guanine + cytosine), restriction endonuclease DNA analysis, cellular protein patterns and metabolism inhibition serologic procedures confirm that the organism previously designated as "Mycoplasma incognitus" (Mi) is indeed very closely related to strains of M. fermentans. While the genetic and serologic features observed among the newly isolated mycoplasma and two M. fermentans strains suggest a species relationship, it now seems useful to re-examine the biological activities of other freshly isolated M. fermentans strains from man.