Combination therapy

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Combination therapy

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Tiff
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01/29/08 - 10:52 PM

An 8 year old boy is brought to the emergency room with an infected wound. The choice of antibiotics o be given in combination therapy must be made. In which of the following combinations would one antibiotic prevent the action of the other antibiotic?

A. Bacitracin and polymyxin

B. Erythromycin and penicillin

C. Erythromycin and tetracycline

D. Neomycin and polymyxin

E. Sulfamethoxazole and trimethroprim

jean robert
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01/30/08 - 02:27 AM

B

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sataleees
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01/30/08 - 07:28 PM

C. Erythromycin and tetracycline

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sataleees
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01/30/08 - 07:35 PM

tetracyclines inhibit aa-tRNA binding to the acceptor site in the ribosome complex
Erythromycin inhibits the translocation of the polypeptide-tRNA of from the acceptor to the donor site, which would have occured if the 1st step (inhibited by tetracycline) is not inhibited.

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Tiff
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01/30/08 - 10:18 PM

Apparently the reasons mention by sataleees would make erythromycin and tetracyclin complimentary to each other instead of preventing the action of each other since they are both bacteriostatic and both inhibit the ribosome.

Tiff
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01/30/08 - 11:17 PM

jean robert is right. nod

B is the correct answer (erythromycin and penicillin). Erythromycin is bacteriostatic, it inhibits cell growth by acting on the ribosome. Penicillin requires cell growth to act on the bacterial cell.

sataleees
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01/31/08 - 05:19 PM

yeah right smiling face

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