Study on possibility of using dry milk as cholesterol source instead of horse serum for cultivation of Ureaplasma urealyticum

Ureaplasma urealyticum is an opportunistic bacteria which is able to cause some human diseases, such as: urethritis, abortion, respiratory dysfunction syndrome in infants and infertility. Culture of clinical specimen is the main diagnosis method of U. urealyticum which is not normally done in clinical laboratories due to unreasonable costs. One of the important reasons for difficulty and costly of U. urealyticum culture is presence of normal horse serum in its media as a source of cholesterol. In this study, it was tried to reduce the rate of expenses and difficulty of U. urealyticum cultivation with proposing an inexpensive and suitable complement instead of horse serum. In this research dry milk was examined as an alternative complement.

Vaginal specimen sampling and cultivation on PPLO broth and PPLO agar was used for isolation U. urealyticum. Different concentrations of dry milk (20, 10, 5, 2/5, 1/25%) was added into PPLO Broth medium before autoclaving. PCR was used for confirmation of presence of U. urealyticum in vaginal specimen (and also confirmation of growth of U. urealyticum on media with dry milk) as well as attention to colony shape and using of MnCl2.

This study showed that U. urealyticum can grow on a media with dry milk as a cholesterol source complement. Media containing less concentration of dry milk showed more to provide U. urealyticum growth. The maximum growth was found in a medium with 1.25% of dry milk while a medium with 20% dry milk did not show any growth of U. urealyticum.

U. urealyticum can grow on media that horse serum is replaced by dry milk as a cholestrol source.