A 19-year-old college freshman living in a university residence hall develops severe headache, neck stiffness, and fever. When he cannot be aroused, he is transported to the hospital where a Gram stain of a centrifuged cerebral spinal fluid shows Gram-negative diplococci. A latex particle agglutination test confirms the etiological cause of the bacterial meningitis. Which causative agent is most likely?
A 19-year-old Iowan dirt bike racer, who raced for the first time in the desert southwest 3 weeks ago, presents in September with cough, malaise, low-grade fever, myalgias, and chest pain. Rales are heard and respiratory infiltrates are noted on radiograph. Sputum stained with calcofluor white and viewed on an ultraviolet microscope shows large blue-white fluorescing spherical structures (with a wall) and with numerous small round cells inside. What is the most likely causative agent?
A 19-year-old male college student came to the Student Health Services complaining of a sore throat, fatigue, and difficulty in swallowing. A physical examination showed an enlarged spleen; a palpable, tender liver; and swollen cervical lymph nodes. His blood is positive for heterophile antibody. What would you expect to see in a blood smear?
A 15-year-old girl has symptoms that include a low-grade fever, chills, headache, muscle aches, and malaise. A physical examination indicates an enlarged spleen. A Monospot test is negative. The laboratory finding that would confirm a diagnosis would be
A 15-year-old man who recently returned from camping in Canada presents with fatty diarrhea and acute abdominal pain following many meals. How does the most likely agent cause the diarrhea?
A 16-year-old boy on antibiotics to clear up a community-acquired methicillin-resistant Staphylococcus aureus has clindamycin added to his treatment regimen to slow the production of the various toxins including Panton-Valentine leukocidin. He recovers but develops Clostridium difficile diarrhea. Why does C. difficile cause diarrhea?
A 16-year-old develops Neisseria meningitidis meningitis. What was the first event?
A 15-year-old boy presents at your office with a sore throat, fever, and enlarged lymph nodes. His tonsils are enlarged, the pharynx is inflamed, and splenomegaly is observed. He complains of severe fatigue. Confirmation of the causative agent is best done by observing.
A 12-day-old neonate has been brought to his pediatrician because the infant has developed a sharp cough. Physical examination also reveals a mild conjunctivitis with some pus; a chest film confirms pneumonia. No organisms are seen on Gram stain of the pus. What is the most likely causative agent?
A 14-month-old child living in a religious community that does not vaccinate their children develops meningitis. A Gram-negative rod is seen in the cerebrospinal fluid. What is the most likely causative agent?