Mycoplasma and Epidemic Group A Meningococcal Meningitis-Reply

Abstract

In Reply. — As Drs Kenny and Foy point out, mycoplasma contamination of cell cultures is a common and insidious problem. We are confident that the M hominis isolated in our study came from the specimens and not the cell cultures due to the precautions taken to avoid and detect contamination. Ten uninoculated control cell cultures of each cell type were passaged in parallel with each batch of inoculated cultures; none of these controls became positive. As part of our quality assurance policies, each cell line is also tested monthly for mycoplasma at the Centers for Disease Control using an adenosine phosphorylase test (Mycotect, Gibco) and at the American Type Culture Collection (Rockville, Md) using both direct culture on Hayflick's medium and a DNA fluorescent staining test. 1,2 All three tests were consistently negative throughout the study period. Furthermore, when study specimens were positive for mycoplasma, all four cell types