Question

multiple choice question
one important reason that antibiotic treatment can result in a colon infection by clostridium difficile is that
antibiotics dont reach the colon when taken by mouth
c. difficile is becoming resistant to most antibiotics used clinically
many patients dont complete the entire course of antibiotic that is prescribed
antibiotics alter the normal microbiota, allowing c. difficile to proliferate
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Explanation:

To determine the correct answer, we analyze each option:

• Option "antibiotics don't reach the colon when taken by mouth": Oral antibiotics do reach the colon (though some may be absorbed earlier), so this is incorrect.
• Option "C. difficile is becoming resistant to most antibiotics used clinically": While resistance is a concern, the main reason for C. difficile infection after antibiotic treatment is disruption of normal microbiota, not primary resistance of C. difficile to most clinical antibiotics.
• Option "many patients don't complete the entire course of antibiotic that is prescribed": Not completing antibiotics can lead to other issues, but the key for C. difficile is microbiota disruption, not incomplete courses as the main reason.
• Option "antibiotics alter the normal microbiota, allowing C. difficile to proliferate": Antibiotics kill beneficial gut bacteria (normal microbiota), which normally keep C. difficile in check. When this balance is disrupted, C. difficile can overgrow and cause infection. This matches the known mechanism.

Answer:

The correct option is "antibiotics alter the normal microbiota, allowing C. difficile to proliferate" (the fourth option in the list).