Synthetic cathelicidin offers new antibacterial options against resistance

Steps:

• Statement 1 is incorrect because synthetic compounds can still face bacterial resistance through evolution.
• Statement 2 is correct as substituting cathelicidin for tetracycline reduces selective pressure, allowing sensitive bacteria to outcompete resistant ones.
• Statement 3 is inaccurate since bacteria could resist via other mechanisms like efflux pumps, not just lipid changes.
• Statement 4 is correct because cathelicidin targets resistant strains lacking effective treatments.

Why D is correct:

• It pairs mechanisms reducing resistance spread (via substitution) with direct treatment of resistant bacteria, per evolutionary principles of antibiotic stewardship.

Why the others are wrong:

• A: Includes false claim in 1 that bacteria cannot resist synthetics.
• B: Relies on invalid 1, ignoring resistance potential.
• C: Features misleading 3 limiting resistance pathways unrealistically.

Final answer: D