I S . IDENTIFICATION OF MYCOPLASMAS
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T A B L E I
Taxonomy of class Mollicutes
Class : Mollicutes
Order I : Mycoplasmatales
Family I : Mycoplasmataceae
Genus I: Mycoplasma
1. Sterol required for growth
2. Sensitive to digitonin
3. Genome size 4.5 x los daltons
1. Sterol required for growth
2. Sensitive to digitonin
3. Urea catabolised
4. Genome size 4.5 x lo* daltons
Genus I I : Ureaplasnta
Family I1 : Acholeplasmataceae
Genus 1 : Acholeplasma
1. Sterol not required for growth
2. Resistant to digitonin
3. Genome size 1 .O x lo9 daltons
Family I I I : Spiroplasmataceae
Genus I : Spiroplasma
1. Sterol required for growth
2. Sensitive to digitonin
3. Helical morphology, rotational and undulating motility
4. Genome size 1 .O x lo9 daltons
Genera of uncertain afiliation
A. Anaeroplasnta
1. Some strains require sterols, some do not
2. Some strains are resistant to digitonin, some are sensitive
3. Strict anaerobes
4. Genome size: not determined
1. Sterol not required for growth
2. Sensitivity to digitonin: not determined
3. Optimum temperature about 59°C and optimum pH 1-2
4. Genome size 1 .O x lo9 daltons
B. Thermoplasma
the definition is intended to exclude from the Mollicutes the L-phase
variants and similar aberrant bacterial forms which are also characterised
by the absence of a complete cell wall and by a number of other properties
derived from this basic feature (Edward, 1967; Freundt, 1973). On the
practical level, classification of an organism as a member of the order
Mycoplusmatules, class Mollicutes, is based primarily on the following
criteria: absence of a cell wall, typical “fried egg” appearance of the
minute colonies, filterability through a membrane filter of 450nm pore