For which of the following indications is clindamycin FDA-approved?

Clindamycin is an antibiotic that is specifically FDA-approved for the treatment of bacterial infections. It works by inhibiting protein synthesis in bacteria, making it effective against a variety of gram-positive bacteria, including some strains of Staphylococcus and Streptococcus. Clindamycin is particularly useful for treating skin and soft tissue infections, respiratory tract infections, and certain dental infections.

The other options do not align with the approved uses of clindamycin. Viral infections, fungal infections, and parasitic infections are not susceptible to clindamycin as they require different types of treatments, such as antiviral medications, antifungals, or antiparasitics, respectively. Thus, the indication for bacterial infectious diseases correctly reflects clindamycin's intended use in clinical practice.