Bacteria — MCQs

A 29-year-old man presents to the clinic complaining of fatigue and loss of sensation in his lower legs. The patient notes no history of trauma or chronic disease but states that he spends a lot of time outside and often encounters wild animals. On examination, the patient has multiple dark lesions over the skin of his face and back, as well as a decreased sensation of fine touch and vibration bilaterally in the lower extremities. What is the morphology of the etiologic agent causing this patient’s symptoms?

A 31-year-old female presents to the emergency room complaining of fever and difficulty breathing. She first noticed these symptoms 3 days prior to presentation. Her past medical history is notable for well-controlled asthma. She does not smoke and drinks alcohol socially. Upon further questioning, she reports that her urine is tea-colored when she wakes up but generally becomes more yellow and clear over the course of the day. Her temperature is 100.8°F (38.2°C), blood pressure is 135/90 mmHg, pulse is 115/min, and respirations are 20/min. Lung auscultation reveals rales at the right lung base. Laboratory analysis is shown below: Hemoglobin: 9.4 g/dL Hematocrit: 31% Leukocyte count: 3,700 cells/mm^3 with normal differential Platelet count: 110,000/mm^3 Reticulocyte count: 3% A chest radiograph reveals consolidation in the right lung base and the patient is given oral antibiotics. Which of the following processes is likely impaired in this patient?

A 59-year-old woman comes to the emergency department because of abdominal pain and bloody diarrhea that began 12 hours ago. Three days ago, she ate undercooked chicken at a local restaurant. Blood cultures grow spiral and comma-shaped, oxidase-positive organisms at 42°C. This patient is at greatest risk for which of the following complications?

A 22-year-old woman comes to the urgent care clinic with sudden onset of severe vomiting. She had been at a picnic with her boyfriend a few hours earlier, enjoying barbecue, potato salad, and cake. Shortly thereafter, she began vomiting and has vomited 5 times in the last 3 hours. She has no prior history of symptoms. After a few hours of observation, her symptoms abate, and she is safely discharged home. Which of the following is the most likely cause of her vomiting?

A 55-year-old woman presents to her primary care physician for a worsening cough. She states that she has had a cough for 5 months. Over the past 2 weeks, the cough has become more frequent and produces yellow sputum. She has dyspnea on exertion at baseline, which she feels is also worsening. She denies fever, hemoptysis, or chest pain. She has chronic obstructive pulmonary disease and mild osteoarthritis. She uses inhaled ipratropium and takes ibuprofen as needed. She received the influenza vaccine 2 months ago. She smokes a half pack a day, and denies alcohol or recreational drug use. In addition to broad-spectrum antibiotics, which of the following is indicated?

Part of the success of the Streptococcus pyogenes bacterium lies in its ability to evade phagocytosis. Which of the following helps in this evasion?

A 55-year-old woman comes to the physician because of fevers for 2 weeks. She works as a nurse and recently returned from a charity work trip to India, where she worked in a medically-underserved rural community. A tuberculin skin test 3 months ago prior to her trip showed an induration of 3 mm. Physical examination is unremarkable. An x-ray of the chest shows right-sided hilar lymphadenopathy. A sputum culture shows acid-fast bacilli. Which of the following immunologic processes most likely occurred first?

A 78-year-old man presented to his primary physician with a 3-month history of weight loss, fever, fatigue, night sweats, and cough. He is a former smoker. A recent HIV test was negative. A CT scan of the chest reveals a 3 cm lesion in the lower lobe of the left lung and calcification around the left lung hilus. A sputum smear was positive for acid fast organisms. These findings are most consistent with which of the following:

A 70-year-old man with loose stools over the last 24 hours, accompanied by abdominal pain, cramps, nausea, and anorexia, was hospitalized. Previously, the man was diagnosed with a lung abscess and was treated with clindamycin for 5 days. Past medical history was significant for non-erosive antral gastritis and hypertension. He takes esomeprazole and losartan. Despite the respiratory improvement, fevers and leukocytosis persisted. Which of the following pathogenic mechanisms would you expect to find in this patient?

A previously healthy 25-year-old male comes to his primary care physician with a painless solitary lesion on his penis that developed 4 days ago. He has not experienced anything like this before. He is currently sexually active with multiple partners and uses condoms inconsistently. His temperature is 37.0°C (98.7°F), pulse is 67/min, respirations are 17/min, and blood pressure is 110/70 mm Hg. Genitourinary examination shows a shallow, nontender, firm ulcer with a smooth base along the shaft of the penis. There is nontender inguinal adenopathy bilaterally. Which of the following is the most appropriate next step to confirm the diagnosis?