Antibiotic failure.

There are many possible causes of antibiotic drug failure, but the most common are drug fevers, untreatable infectious diseases, noninfectious diseases, or problems with incorrect or inadequate spectrum. Failure to respond to antibiotics includes the emergence of resistant organisms, superinfections, and drug interactions. The most common mistake made with apparent antibiotic failure is to change or add additional antibiotics. The most important strategy is to analyze the cause of the antibiotic failure by careful evaluation and use of appropriate diagnostic tests to avoid needless, expensive, and potentially dangerous antimicrobial therapy.