A 50-year-old man presents with fever, confusion, and hypotension one week after a camping trip. His family reports that he had a rash starting on his wrists and ankles, but it has now become purpuric and widespread. Lab tests show thrombocytopenia, hyponatremia, and elevated liver enzymes. Despite treatment, his condition worsens, and he develops renal failure and respiratory distress. Which of the following is the most likely cause of his worsening condition?
