Studies on the activity of Obioactin with acetylspiramycin on mice infected with Toxoplasma gondii.

In acutely infected mice, acetylspiramycin (ASPM) administered in combination with Obioactin , or sulfamethoxypyrazine ( SMPZ ), prevented Toxoplasma organisms from encysting in the brain and heart tissues. When administered alone, ASPM prevented these organisms from encysting in the heart but not in the brain. All the regimens used failed to reduce the bulk of parasites in the brain and heart tissues of chronically infected mice. Treatment with an ASPM- Obioactin combination, however, brought about the most remarkable reduction, or 52.4%, of the cyst count in the brain of all the methods of treatment applied. Light and electron microscopy of the mice with chronic Toxoplasma infection revealed no changes in the brain or heart tissue of the ASPM- Obioactin treated mice and degenerative changes in the cyst wall and bradyzoites and a remarkable increase of microglias with cysts in the brain in some of these mice.