PLE Category: Microbiology

PLE-3587

A 23-year-old male with a month-long history of nonproductive cough, intermittent fever, and night sweats came in for a consult. A sputum sample was sent to the local health center and tested positive for AFB. Which of the following virulent factors of the etiologic agent allow it to inhibit leukocyte migration, disrupting mitochondrial respiration, and oxidative phosphorylation in cells?

PLE-3588

Septicemic shock is primarily due to which bacterial structure in Gram-negative organisms?

PLE-3586

A 22-year-old male initially complains of bilateral foot and hand tingling. The symptoms then rapidly progressed over a week to include lower extremity weakness. He is brought to the clinic because he is no longer able to ambulate. On physical examination, motor strength is 0/5 on both lower extremities, reflexes are decreased, and the rest of the neurological examination was unremarkable. Lumbar puncture revealed mildly elevated protein with no cells and normal glucose. A few weeks prior, the patient reported having stomach flu. What is the most likely infectious trigger of the patient’s condition?

PLE-3584

A 30-year-old male who was in a vehicular crash underwent exploratory laparotomy and splenectomy. He would require immunizations against which of the following pathogens?

PLE-3585

A recent study by Albert et al. in the NEJM made the case for the use of Azithromycin in the prevention of exacerbations of COPD. This is because Azithromycin is active against the most common bacterial cause of COPD, which is:

PLE-3583

A 1/M infant consults for paroxysms of violent coughing. You note cyanosis around his lips during coughing. Parents note that the patient had symptoms of the common colds for a few weeks prior. Patient has not had any immunizations since birth. To identify the etiologic organism, you take a nasopharyngeal aspirate. On which culture medium would the most likely etiologic agent grow?

PLE-3580

A 57-year-old man with multiple myeloma comes to the physician because of a 12-hour history of fever, sharp chest pain with deep inspiration, and cough productive of blood-tinged sputum. His temperature is 38.3 C (101 F), blood pressure is 120/78 mm Hg, pulse is 112/min, and respirations are 28/min. Crackles are heard at the right lung base. His hemoglobin level is 9.2 g/dL, leukocyte count is 2600/mm3, and platelet count is 6,000/mm3. Which organisms should empiric antibiotics be directed against?

PLE-3581

An 82-year-old man comes to the physician because of a 3-day history of low back pain that radiates to the right leg. He also has had a lesion over the right shin and weakness of the right foot. He began taking prednisone 2 weeks ago for acute bronchitis. He has chronic obstructive pulmonary disease, benign prostatic hypertrophy, and glaucoma. Examination shows numerous papular and vesicular lesions over the right anterior and posterior shin. There is weakness of right knee flexion, ankle dorsiflexion, plantar flexion, eversion, and inversion; the right ankle reflex is absent. Sensation to pinprick and cold is decreased over the right lower extremity. What is the most likely causal organism?

PLE-3582

Gram staining of a sample sent to the laboratory revealed Gram-positive lancet-shaped cocci in pairs. Colonies exhibited partial hemolysis on blood agar. Biochemical testing reveals that the bacterium is optochin sensitive. What is the most common cause of the isolated bacterium?