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Biology-Related Homework Help Medicine Topic started by: lpooziee on Jan 24, 2018



Title: A child with otitis media has had three ear infections in the past year. The child has just ...
Post by: lpooziee on Jan 24, 2018
A child with otitis media has had three ear infections in the past year. The child has just completed a 10-day course of amoxicillin (Amoxil) with no improvement.
 
  The parent asks the nurse why this drug is not working, because it has worked in the past. What will the nurse tell the patient?
  a. Amoxicillin is too narrow in spectrum.
  b. The bacteria have developed a three-layer cell envelope.
  c. The bacteria have developed penicillin-binding proteins (PBPs) that have a low affinity for penicillins.
  d. The bacteria have synthesized penicillinase.


Title: A child with otitis media has had three ear infections in the past year. The child has just ...
Post by: ahmedtalaat1976 on Jan 24, 2018
ANS: D
Beta-lactamases are enzymes that cleave the beta-lactam ring and render the PCN inactive. This resistance is common with organisms that cause ear infections. Amoxicillin is a broad-spectrum antibiotic. A three-layer cell envelope occurs in gram-negative bacteria. Some bacterial strains, including methicillin-resistant Staphylococcus aureus (MRSA), develop PBPs with a low affinity for penicillins. MRSA is not a common cause of otitis media.