Effects of manganese on the growth and morphology of Ureaplasma urealyticum.

All of the 14 serotype standard strains of Ureaplasma urealyticum were inhibited to varying degrees by manganese. A 1 mM concentration of this cation either stopped growth or reduced the rate of growth in liquid medium. The presence of manganese also altered colonial morphology and cellular ultrastructure. Inhibition was dose dependent and strain specific. This differential response allowed the serotype strains to be divided into two broad biotypes. For the first biotype (serotypes 1, 3, 6, and 14), inhibition of growth in broth was temporary. For the second biotype (serotypes 2, 4, 5, 7, 8, 9, 10, 11, and 12), inhibition was permanent. Serotype 13 gave an intermediate response and was not classified. The effect of manganese could be at least partially blocked by magnesium but not by calcium, cobalt, copper, iron, potassium, sodium, or zinc. The concentration of magnesium yielding the maximum blocking effect was directly related to manganese sensitivity. Wild-type isolates of ureaplasma and Mycoplasma hominis also showed a differential response to manganese. Laboratory-adapted strains representing species of the genus Mycoplasma (M. hominis, M. fermentans, and M. pneumoniae) were inhibited by 5 but not by 1 mM manganese. The latter concentration inhibited the growth of Acholeplasma laidlawii and Staphylococcus aureus, and 5 mM manganese had no effect on Escherichia coli.