INTRODUCTION

Mycoplasmas, Acholeplasmas, and Ureaplasmas are small prokaryotes, all belonging to the Mollicutes class—a class of bacteria lacking a cell wall and surrounded by a deformable membrane. Mycoplasmas are contaminants found in biopharmaceutical, biologic, and mammalian cell culture processes that may infect eukaryotic cells, and, as such, they are less likely to contaminate small-molecule pharmaceutical processes and products. Mycoplasmas can be associated with microbiological growth media such as Soybean–Casein Digest Medium (SCDM). Mycoplasmas are easily inactivated by heat and radiation and are therefore not a concern where process streams are terminally sterilized. However, where sterilizing filtration is employed, the presence of mycoplasmas must be considered in designing filter validation studies. The small size (0.15–0.3 µm) and flexibility of the organism allows its passage through the 0.2-µm-rated microporous membrane filters commonly used to sterilize liquid pharmaceutical process streams.