Susceptibility of Human Mycoplasmata to Ultraviolet and X Irradiations

Abstract

The minimal reproductive unit or elementary body of Mycoplasma pneumoniae is a single cell 150 mix in size, but colony-forming units in broth are usually clusters of elementary bodies. A method for obtaining single elementary body suspensions demonstrated that elementary bodies of M. pneumoniae are killed exponentially by UV light and X rays, with 99% being inactivated in 7.5 sec. by UV light and by 30,000 r of X ray, respectively. The rates of inactivation are independent of concentration. Broth cultures of M. pneumoniae are not killed exponentially confirming that they contain clusters of elementary bodies; M. fermentans and M. orale are also susceptible to UV. A technique for differentiating mycoplasmata from pseudocolonies by means of sensitivity to UV irradiation was desc ribed.