Antibiotics — MCQs

A typically healthy 27-year-old woman presents to the physician because of a 3-week history of fatigue, headache, and dry cough. She does not smoke or use illicit drugs. Her temperature is 37.8°C (100.0°F). Chest examination shows mild inspiratory crackles in both lung fields. An X-ray of the chest shows diffuse interstitial infiltrates bilaterally. A Gram stain of saline-induced sputum shows no organisms. Inoculation of the induced sputum on a cell-free medium that is enriched with yeast extract, horse serum, cholesterol, and penicillin G grows colonies that resemble fried eggs. Which of the following is the most appropriate next step in management?

A 76-year-old man comes to the physician for a follow-up examination. One week ago, he was prescribed azithromycin for acute bacterial sinusitis. He has a history of atrial fibrillation treated with warfarin and metoprolol. Physical examination shows no abnormalities. Compared to one month ago, laboratory studies show a mild increase in INR. Which of the following best explains this patient's laboratory finding?

A 26-year-old woman comes to the physician because of a 3-day history of redness, foreign body sensation, and discharge of both eyes. She reports that her eyes feel “stuck together” with yellow crusts every morning. She has a 3-year history of nasal allergies; her sister has allergic rhinitis. She is sexually active with 2 male partners and uses an oral contraceptive; they do not use condoms. Vital signs are within normal limits. Visual acuity is 20/20 in both eyes. Ophthalmic examination shows edema of both eyelids, bilateral conjunctival injection, and a thin purulent discharge. Examination of the cornea, anterior chamber, and fundus is unremarkable. The remainder of the examination shows no abnormalities. Which of the following is the most appropriate pharmacotherapy?

A 24-year-old woman presents to her physician's office complaining of a worsening cough with large volumes of mucoid sputum every morning and thick, foul-smelling sputum almost every time she coughs. She says that this cough started about one month ago and has been increasing in intensity. Over-the-counter medications are ineffective. Past medical history is significant for cystic fibrosis diagnosed at the age of 6 years, and pneumonia twice in the past 2 years. Other than a cough, she has no fever or any other concerns. A sputum sample grows aerobic, non-lactose fermenting, oxidase-positive, gram-negative bacillus. Which of the following treatment regimens is the most beneficial for her at this time?

A 27-year-old woman comes to the emergency room because of fever and severe left knee pain for the past week. She has not sustained any trauma or injury to the area, nor has she traveled or taken part in outdoor activities in the recent past. She is sexually active with one male partner, and they use condoms inconsistently. She appears ill. Her temperature is 38°C (100.4°F), pulse is 98/min, respirations are 17/min, and blood pressure is 106/72 mm Hg. Physical examination shows multiple painless pustular lesions on her ankles and the dorsum and soles of her feet bilaterally, as well as a swollen, erythematous, exquisitely tender left knee. Her wrists are also mildly edematous and tender, with pain on extension. X-ray of the knees shows tissue swelling. Arthrocentesis of the knee shows yellow purulent fluid. Gram stain is negative. Analysis of the synovial fluid shows a leukocyte count of 58,000/mm3 with 93% neutrophils and no crystals. Which of the following is the most appropriate pharmacotherapy?

An 11-year-old girl is brought to the emergency department because of high-grade fever, headache, and nausea for 3 days. She avoids looking at any light source because this aggravates her headache. She has acute lymphoblastic leukemia and her last chemotherapy cycle was 2 weeks ago. She appears lethargic. Her temperature is 40.1°C (104.2°F), pulse is 131/min and blood pressure is 100/60 mm Hg. Examination shows a stiff neck. The pupils are equal and reactive to light. Neck flexion results in flexion of the knee and hip. Muscle strength is decreased in the right upper extremity. Deep tendon reflexes are 2+ bilaterally. Sensation is intact. Extraocular movements are normal. Two sets of blood cultures are obtained. Which of the following is the most appropriate next step in management?

A 62-year-old woman has been receiving amoxicillin for acute sinusitis for 12 days. She develops a macular rash on her neck, back, and torso. The amoxicillin is therefore changed to cephalexin for an additional week. The rash resolves, but she returns complaining of fatigue, flank pain, and fever that has persisted despite the resolution of the sinusitis. She has a history of essential hypertension, hyperlipidemia, and gastric reflux. She has been on a stable regimen of lisinopril, simvastatin, and omeprazole. Today, her vital signs reveal: temperature 37.9°C (100.2°F), blood pressure 145/90 mm Hg, regular pulse 75/min, and respirations 16/min. The physical examination is unremarkable. Serum urea and creatinine are elevated. Urinalysis shows leukocyturia, but urine bacterial culture is negative. A urine cytospin stained with Hansel’s solution reveals 3% binucleated cells with eosinophilic, granular cytoplasm. Which of the following is the most likely diagnosis?

A 27-year-old man presents to the emergency department after a dog bite. The patient was intoxicated and pulled the dog’s tail while it was eating. The dog belongs to his friend and is back at his friend’s house currently. Physical exam is notable for a dog bite on the patient’s right arm. The wound is irrigated and explored with no retained bodies found. A tetanus vaccination is administered. Which of the following is appropriate management of this patient?