A 33-year-old woman with nausea, vomiting, and diarrhea after eating a chicken meal at a country picnic presents to the emergency department. Her serum electrolytes are within normal limits. She is placed on amoxicillin and given an antidiarrheal agent. She returns for follow-up in 1 week with worsening of diarrhea and abdominal pain. What is the most likely explanation for these findings?

A 33-year-old woman with nausea, vomiting, and diarrhea after eating a chicken meal at a country picnic presents to the emergency department. Her serum electrolytes are within normal limits. She is placed on amoxicillin and given an antidiarrheal agent. She returns for follow-up in 1 week with worsening of diarrhea and abdominal pain. What is the most likely explanation for these findings?

A 54-year-old man with a history of recurrent pulmonary tuberculosis is placed on a multidrug regimen, including isoniazid. Despite long-term therapy with this agent, the treating physician has concerns about resistance. The most likely mechanism for this to occur is which of the following?

A 54-year-old man with tuberculosis is maintained on a multidrug regimen including cycloserine. He complains of intermittent chest pressure and dyspnea but this does not limit his daily activities. On a cellular level, which of the following amino acids is blocked by this agent?

A 34-year-old man is hospitalized with seizures, headache, and vomiting. CT scan of the brain reveals cysticercosis. What is the most appropriate treatment for this patient?

A 45-year-old woman complains of facial wrinkles and lines. She heard of a drug for wrinkles from a friend that is a bacterial toxin and works by paralyzing skeletal muscles. What is the mechanism of action of this drug?