Management of mycoplasma contamination in in vitro culture of Plasmodium falciparum without antibiotic treatment – a preliminary report

The presence of foreign contamination, especially of mycoplasmas, is a major hindrance in long term in vitro cultivation of Plasmodium falciparum and may be a source of false-positive results. Efforts have been made to control mycoplasma contamination by trypsinization of P. falciparum culture. Samples of accidentally contaminated cultures were used for this study. The presence of Mycoplasma orale in contaminated culture was ascertained by a species-specific PCR-based mycoplasma detection kit (Takara; Cat. No.6601). Trypsinization was carried out using trypsin-EDTA and the growth profile of P. falciparum was monitored for more than three weeks post-trypsinization. The studies were carried out with four different P. falciparum strains, various serum supplements and human erythrocytes belonging to different blood groups. It was interesting to observe that, irrespective of the different strains of P. falciparum and the variety of serum supplements and erythrocytes, mycoplasma contamination can successfully be removed from P. falciparum culture by trypsinization. No antibiotic except gentamicin, which is routinely used, was added to the medium. Results of this study indicate that the frequent appearance of mycoplasma in continuous long-term cultures of P. falciparum can be managed by trypsinization.