Intracellular DNA replication and long-term survival of pathogenic mycoplasmas

We examined intracellular survival and growth of pathogenic mycoplasmas (Mycoplasma penetrans, Mycoplasma pneumoniae and Mycoplasma genitalium) in cultured human cells. By using the eukaryotic nuclear DNA synthesis inhibitor, aphidicolin, we detected the selective synthesis of mycoplasma (My) and mitochondria (Mt) DNA, which could be further differentiated by restriction enzyme analyses. Also, intracellular M. pneumoniae and M. penetrans infectivity of human cells was detected over 6 months using subfractionation of infected cells and determination of mycoIplasma colony forming units (cfu). For M. genitalium, which we failed to re-grow from infected cells, species-specific PCR primers were used to implicate long-term mycoplasma survivability. Data indicated that pathogenic mycoplasmas reside and replicate intracellularly over extended periods in human cells, consistent with the ability of mycoplasmas to circumvent antibiotic therapy and immune surveillance and establish chronic infections.