Ureaplasma urealyticum gen. nov., sp. nov.: Proposed Nomenclature for the Human T (T-Strain) Mycoplasmas

Abstract

The biological properties and special characteristics of the human T mycoplasmas have been reviewed and summarized. The T mycoplasmas are distinguished from all other known mycoplasmas by their production of urease, and, therefore, by their ability to hydrolyze urea. This singular property significantly sets the T mycoplasmas apart from all other members of the order Mycoplasmatales. In consideration of this distinguishing property, it is reasonable to propose establishing a new, separate genus in the family Mycoplasmataceae in which t o classify the T mycoplasmas isolated from man and lower animals. The name Ureaplasma is proposed for this new genus, which at present contains a single human species of at least eight different serotypes. The name Ureaplasma urealyticum is proposed for this new species. The type strain of U. urealyticum is human strain 960-(CX8), serotype VIII (Black); it has been deposited in the American Type Culture Collection as ATCC 27618.T mycoplasmas were first recognized and identified in 1954 in primary agar cultures of urethral exudates from male nongonococcal urethritis patients. They were called "tiny-form PPLO" (pleuropneumonia-like organisms) and "T-form colonies of PPLO" after the minute size, distinctive characteristics, and morphology of their agar colonies. The first published reference to these unusual mycoplasmas was a brief description accompanying two photomicrographs of "T" colonies in a primary agar culture of urethral exudate (53). Subsequent studies confirmed that T mycoplasmas were new, previously undescribed members of the human mycoplasma group. Their distinctive morphology and cultural characteristics were described and illustrated in detail in 1956 (54).The original minute colony size (10 * 5 pm) was the result of nutritionally inadequate culture media of distinctly unfavorable alkaline reaction (pH 7.8 to 8.0) resulting in near threshold performance in supporting growth of T mycoplasmas. Some of the early failures of other investigators t o isolate T mycoplasmas from clinical exudates may also be explained by the incorporation by these investigators of thallium acetate in the medium in accordance with standard classical mycoplasma methodology. This antibacterial agent is almost completely inhibitory t o many strains of T mycoplasmas in primary agar cultures in alkaline media of pH 7.8 t o 8.0. Thallium acetate was never employed in Shepard's laboratory , where only penicillin was incorporated as an antibacterial agent (1,000 U/ml).Prior to 1966, identification of T mycoplasmas in primary cultures was limited exclusively to characteristic minute size, morphology, and staining reaction of agar colonies. The subsequent development of improved agar culture media made identification based upon the above-mentioned criteria less reliable, since T colonies were no longer really "tiny." Identification was especially difficult under conditions of crowding in mixed mycoplasma cultures since classical mycoplasma colonies often completely lost the ability to produce the surface...

Production of Mastitis in Mice With Human and Bovine Ureaplasmas (T-Mycoplasmas)

“…CD408, M126/68 and CD573, have been described previously . Strain CD591 (Johnson) was isolated from the human oropharynx (Taylor-Robinson and Purcell, 1966) and strain T960 is the type strain of Ureaplasma urealyticum (Shepard et al, 1974). Strains A417, Vic9, Bu2 and BlOl were isolated from cattle (Howard et al, 1973).…”

Ureaplasma canigenitalium sp. nov., Isolated from Dogs

“…Ureaplasmas have been isolated from a variety of animal species, including humans (23), cattle (28), nonhuman primates (29), goats (7), sheep (19), dogs (29), cats (27), mink (6), raccoon dogs (16), pigs (26), and fowl (25). Previously the following five species of the genus Ureaplasma have been described: Ureaplasma urealyticum (type strain, T960 [= ATCC 27618]), isolated from a patient with nongonococcal urethritis (24); Ureaplasma diversum (type strain, A417 [= ATCC 43321]), isolated from cattle with pneumonia (10); Ureaplasma gallorale (type strain, D6-1 [= ATCC 43346 = NCTC 11707]), isolated from the oropharynx of a chicken (17); and Ureaplasma felinum (type strain, FT-2B [= ATCC 49229 = NCTC 117091) and Ureaplasma cati (type strain, F2 [= ATCC 49228 = NCTC 11710]), both of which were isolated from the oral cavities of cats (8). There are at least 14 serovars of U. urealyticurn and three serovars of U. diversum.…”

Some Characteristics of Ureaplasma urealyticum. Urease Activity in a Simple Buffer: Effect of Metal Ions and Sulphydryl Inhibitors

“…The ability to hydrolyse urea is given as the major differentiating characteristic of Ureaplasma urealyticum (Shepard et al, 1974). Recently, this urealytic activity was studied using a crude cytoplasmic preparation from U. urealyticum (Masover et al, 1976).…”