A 28-year-old woman has seropurulent conjunctivitis and complains of painful urination. A conjunctival scrape was obtained for analysis. Microscopy shows inclusions in the cytoplasm of the epithelial cells. Inoculation of the pathologic material onto nutrient media produced no growth. However, inoculation of chicken embryos by the yolk sac route allowed obtaining the culture of the causative agent. What microorganism is the most likely causative agent?