When selecting antibiotics, what principle helps prevent resistance and adverse effects?

• A. Use the narrowest effective spectrum and tailor therapy to culture results; avoid unnecessary broad-spectrum use
• B. Start with broad-spectrum antibiotics for all infections
• C. Always choose the newest antibiotic
• D. Use antibiotics only for viral infections

Answer: (A)

The principle at work here is antibiotic stewardship: start with the narrowest spectrum that will effectively cover the pathogen and tailor therapy to culture or susceptibility results, avoiding unnecessary broad-spectrum use. This approach minimizes the selective pressure that antibiotics place on the broader microbial community, which is what drives resistance. It also reduces disruption to normal flora, lowers the risk of adverse effects and superinfections like Clostridioides difficile, and generally improves safety and cost.

In practice, you often begin empirically with a regimen that covers the most likely pathogens based on the clinical scenario, but as soon as culture data are available, you de-escalate to a narrower agent that targets the identified organism. This step-down strategy preserves effectiveness for future infections by keeping a diverse reservoir of susceptible bacteria and curbs resistance development.

Other options don’t fit as well: using broad-spectrum antibiotics for all infections drives resistance and increases toxicity; always choosing the newest antibiotic isn’t guaranteed to be better and can worsen resistance and costs; and using antibiotics for viral infections is inappropriate because viruses are not affected by antibiotics.