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Methicillin Resistant Staph Infections and College Athletes

APBIO-JDE7HV

On a college campus, health services began using methicillin to treat S. aureus bacterial infections in its athletes. Within six months of starting this effective treatment method, 85% of all new infections were caused by methicillin-resistant S. aureus organisms.

Which of the following BEST explains this phenomenon?

A

Some drug-resistant bacteria were present at the beginning of the new treatment program, and the addition of the drug methicillin changed the environment so that natural selection increased their frequency.

B

S. aureus altered the structure of the protein targeted by methicillin in response to the drug's presence.

C

A student on the campus must have contracted a methicillin-resistant strain of S. aureus during an away game at another college.

D

S. aureus is unaffected by vaccines and can only be treated by antibiotics.