From the Centers for Disease Control and Prevention in Atlanta:

Mycoplasma pneumoniae usually causes symptoms resembling the common cold, which typically go away without treatment. Some people develop “walking pneumonia,” a mild form of pneumonia; sinusitis; or ear infections —all of which can be treated with antibiotics. Only in one-tenth of 1 percent of cases does a mycoplasma infection involve a central-nervous-system disorder such as encephalitis, a rare inflammation of the brain, or meningitis, an infection of the fluid surrounding the spinal cord or the fluid surrounding the brain.