ATP measurements obtained by luminometry provide rapid estimation of Ureaplasma urealyticum growth.

ATP content obtained by luciferin-luciferase luminometry with commercially available reagents provided rapid estimates of Ureaplasma urealyticum populations. Each cell contained about 4.7 X 10(-18) mol of ATP. We could detect 10(4) CCU50 (color change unit50) per 100 microliters. We correlated urease activity with growth and confirmed the differential response of ureaplasma strains to Mn2+.

Growth characteristics of ureaplasmas from animal and human sources.

Ureaplasma strains isolated from man, nonhuman primates, and canine, feline and avian hosts had less demanding nutritional requirements than did strains obtained from bovine and ovine sources. One millimolar Mn+2 inhibited the growth of most of the ureaplasmas examined, but had a stimulatory effect for at least one strain. The response to Mn+2 appeared to be a characteristic of the individual isolate, rather than of the host from which it was isolated. While two strains of U. urealyticum isolated from man were able to degrade human IgA into two fragments, 13 strains from seven animal species were not.

Immunoglobulin A protease activity of Ureaplasma urealyticum.

All of 14 serotype standards and 34 of 35 wild-type strains of Ureaplasma urealyticum isolated from humans demonstrated an immunoglobulin A (IgA) protease activity. This activity degraded radiolabeled human IgA including IgA1 but not IgG or azocasein. The IgA fragments were detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, followed by radioautography, and they had molecular weights of about 110,000 and 50,000. The IgA protease activity persisted in 25 mM EDTA but was sensitive to trypsin; it was presumed to be protein. This is the fourth microbial genus and the first myocoplasma species in which an IgA protease activity has been identified. Such activity was absent in Mycoplasma pneumoniae, Mycoplasma hominis, and Acholeplasma laidlawii.