What is a key principle of antibiotic use in ophthalmology to minimize resistance?

• A. Use the broadest spectrum to cover all possibilities.
• B. Use the narrowest effective spectrum and base therapy on culture when possible; avoid unnecessary prolonged use.
• C. Avoid culture testing to save time.
• D. Use combination therapy for all cases.

Answer: (B)

In ophthalmic practice, antibiotic stewardship means choose therapy that targets the pathogen as specifically as possible and tailor treatment to culture results whenever available, with as-short-as-necessary duration. Using the narrowest effective spectrum minimizes collateral damage to normal ocular flora and lowers the selective pressure that drives resistance. When you can obtain cultures, identifying the organism and its susceptibilities allows you to de-escalate from a broader agent to a drug with the appropriate activity, without sacrificing efficacy. Avoiding unnecessary prolonged use further reduces the chance that resistant strains will emerge and helps limit adverse effects and costs. In urgent, sight-threatening cases, starting with broader empiric coverage may be necessary, but the goal remains to switch to a targeted, narrow-spectrum regimen as soon as culture data permit. The other approaches promote resistance or unnecessary exposure: broad, all-the-time coverage increases selection pressure; skipping culture delays targeted therapy; and treating every case with combination therapy is not justified and can heighten resistance and toxicity.