Which two topical antibiotics used for typical surface infections offer Gram-positive coverage?

• A. Moxifloxacin and erythromycin.
• B. Ciprofloxacin and gentamicin.
• C. Neomycin and polymyxin B.
• D. Vancomycin and rifampin.

Answer: (A)

The main idea is recognizing antibiotics that provide strong Gram-positive coverage for surface eye infections. Moxifloxacin is a fourth‑generation fluoroquinolone with robust activity against Gram-positive cocci such as Staphylococcus and Streptococcus, and it’s widely used topically for conjunctivitis and other surface infections. Erythromycin is a macrolide that primarily targets Gram-positive organisms and has long been used as an ophthalmic topical agent for similar infections. Together, they cover the common Gram-positive pathogens encountered on the ocular surface.

The other options lean more toward Gram-negative activity (ciprofloxacin, gentamicin, polymyxin B) or include items not typically used together as a standard topical ophthalmic pair (vancomycin with rifampin). Hence, moxifloxacin and erythromycin best fit the goal of Gram-positive coverage for typical surface infections.