A 48-year-old man comes to the emergency department due to fever. He returned from a vacation in Southeast Asia a week ago and began having symptoms toward the end of his trip. He has also had headaches and abdominal discomfort; he initially had constipation but has had loose stools for the past several days. Temperature is 40 C (104 F), blood pressure is 114/68 mm Hg, and pulse is 62/min. No oropharyngeal lesions, cervical lymphadenopathy, or neck rigidity is present. Lungs are clear on auscultation, and heart sounds are normal. Physical examination reveals a faint, erythematous, macular skin rash over the trunk and abdomen. Blood culture grows non-lactose fermenting gram-negative rods. Which of the following best explains the prolonged and severe disease course from this pathogen compared to the patient's previous bacterial infection?

Question

A 48-year-old man comes to the emergency department due to fever.  He returned from a vacation in Southeast Asia a week ago and began having symptoms toward the end of his trip.  He has also had headaches and abdominal discomfort; he initially had constipation but has had loose stools for the past several days.  Temperature is 40 C (104 F), blood pressure is 114/68 mm Hg, and pulse is 62/min.  No oropharyngeal lesions, cervical lymphadenopathy, or neck rigidity is present.  Lungs are clear on auscultation, and heart sounds are normal.  Physical examination reveals a faint, erythematous, macular skin rash over the trunk and abdomen.  Blood culture grows non-lactose fermenting gram-negative rods.  Which of the following best explains the prolonged and severe disease course from this pathogen compared to the patient's previous bacterial infection?

Quizplus · Accepted Answer

Eductional Objective: Typhoid strains of Salmonella contain a capsular antigen (Vi) that inhibits neutrophil phagocytosis, neutrophil recruitment, and macrophage-mediated destruction.  Therefore, typhoid strains are able to undergo extensive replication within the intracellular space of macrophages with subsequent spread through the lymphatic and reticuloendothelial system, leading to a widespread systemic disease (typhoid fever).

A 48-Year-Old Man Comes to the Emergency Department Due to Fever