Effects of carbon dioxide, urea, and ammonia on growth of Ureaplasma urealyticum (T-strain mycoplasma)

Abstract

Using a simple device for continuous CO2 gassing of U. urealyticum cultures growing in a liquid medium, some of the effects of urea, CO2, NH3, and pH on growth was separated. CO2 acted as a superior buffer in the pH 5.7-6.8, which is optimal for Ureaplasma growth. The effect of repeated additions of urea to the culture without alkalinization of the growth medium was observed. Repeated additions of urea did not enhance Ureaplasma growth, and the resultant accumulation of NH4+ (> 2000 .mu.g/ml) did not cause more rapid death under these conditions. By abruptly changing the gaseous environment from CO2 to N2, a rapid pH change occurred in the culture to > 8.0. This resulted in a more rapid death of the organisms.