Antibiotics — MCQs

A 27-year-old woman comes to the physician because of a 2-day history of severe burning pain with urination, and urinary frequency. She has no history of serious illness. The patient and her husband are currently trying to conceive a child. Her only medication is a prenatal multivitamin. Her temperature is 36.5°C (97.7°F), pulse is 75/min, and blood pressure is 125/78 mm Hg. Examination shows mild tenderness to palpation over the suprapubic region. There is no costovertebral angle tenderness. The remainder of the examination shows no abnormalities. Laboratory studies show: Hemoglobin 14.8 g/dL Leukocyte count 8,200/mm3 Platelet count 230,000/mm3 Urine pH 7 WBC 52/hpf RBC 17/hpf Protein negative Nitrites positive Leukocyte esterase positive A urine pregnancy test is negative. Which of the following is the most appropriate next step in management?

A 25-year-old G1P0 woman at 33 weeks gestation presents to the obstetrician for an episode of postcoital spotting. The patient’s pregnancy is complicated by diet-controlled gestational diabetes. She has no other medical conditions. She takes prenatal vitamins. She denies tobacco, alcohol, or recreational drug use. She is currently sexually active with her boyfriend of 1 year, but prior to her current relationship, she states she had multiple male partners. On physical examination, no vaginal bleeding is appreciated. The cervix is closed, and there is no leakage of fluid or contractions. Fetal movement is normal. Fundal height is 33 cm. Fetal pulse is 138/min. The patient’s temperature is 37.0 °C (98.6°F), blood pressure is 112/75 mm Hg, and pulse is 76/min. A urine dipstick is negative for glucose and protein. Chlamydia trachomatis nucleic acid amplification testing is positive. Which of the following is the mechanism behind the first-line treatment for this patient’s condition?

A 27-year-old man presents to the emergency department with loss of consciousness. The patient was brought in 20 minutes ago by the supervisor at a homeless shelter who found him passed out next to a bottle of acetaminophen. The patient has a past medical history of HIV, hepatitis C, IV drug abuse, alcohol abuse, suicide attempt, and constipation. He takes methadone daily but is notably non-compliant with his anti-retroviral therapy. His temperature is 104°F (40°C), blood pressure is 85/40 mmHg, pulse is 180/min, respirations are 18/min, and oxygen saturation is 90% on room air. The patient is started on IV fluids, N-acetylcysteine, and 100% oxygen. Blood cultures are obtained, and lab work is sent off. The patient is then started on broad spectrum antibiotics and given norepinephrine. Repeat vitals demonstrate hypotension and tachycardia. Serum toxicology returns and is positive for alcohol. The patient is transferred to the medicine floor and managed further. Two days later, the patient's vitals have improved. Repeat lab values are ordered and return as follows: Hemoglobin: 11 g/dL Hematocrit: 30% Leukocyte count: 6,500 cells/mm^3 with normal differential Platelet count: 245,000/mm^3 Serum: Na+: 138 mEq/L Cl-: 100 mEq/L K+: 4.1 mEq/L HCO3-: 22 mEq/L BUN: 30 mg/dL Glucose: 145 mg/dL Creatinine: 1.4 mg/dL Ca2+: 9.6 mg/dL AST: 1,440 U/L ALT: 1,350 U/L Which of the following is the best explanation for this patient’s laboratory abnormalities?

A 60-year-old man with a history of coronary artery disease and hyperlipidemia presents to his internist for a follow-up visit 3 weeks after visiting an urgent care center for symptoms of cough, fever, and difficulty breathing. He had been prescribed erythromycin in addition to his usual regimen of rosuvastatin and aspirin. With which potential side effect or interaction should the internist be most concerned?

An investigator is studying a strain of bacteria that retains a blue color after crystal violet dye and acetone are applied. The bacteria are inoculated in a petri dish containing hypotonic saline. After the addition of an antibiotic, the bacteria swell and rupture. This antibiotic most likely belongs to which of the following classes?

A 61-year-old woman comes to the physician because of a 6-day history of cough, shortness of breath, and fever. She also reports that she has had 4 episodes of watery diarrhea per day for the last 3 days. She has chronic bronchitis. She has smoked one pack of cigarettes daily for the past 30 years. Her temperature is 39°C (102.2°F) and pulse is 65/min. Examination shows diffuse crackles over the left lower lung field. Laboratory studies show: Hemoglobin 13.8 g/dL Leukocyte count 16,000/mm3 Platelet count 150,000/mm3 Serum Na+ 131 mEq/L Cl- 102 mEq/L K+ 4.7 mEq/L An x-ray of the chest shows consolidation of the left lower lobe. A Gram stain of induced sputum shows numerous neutrophils but no organisms. Which of the following is the most appropriate pharmacotherapy?

A 14-year-old boy is brought to the emergency department by his parents for joint pain following the acute onset of a diffuse, pruritic rash for the past 24 hours. A week ago, he was diagnosed with pharyngitis after returning home from summer camp and is currently taking antibiotics. There is no family history of serious illness. His temperature is 38.5°C (101.3°F), pulse is 90/min, and blood pressure is 110/70 mm Hg. Physical examination shows periorbital edema, generalized lymphadenopathy, and well-circumscribed, erythematous, confluent skin lesions of variable sizes up to several centimeters in width over his entire body. There is pain on passive movement of wrists and ankle joints bilaterally. Urine dipstick shows 1+ proteinuria. There is no hematuria. Which of the following is the most appropriate next step in management?

A 26-year-old female who is 12 weeks pregnant presents to her primary care physician because she is concerned about her acne. While she has struggled with acne for most of her adult life, the acne has become more severe in the past few months. She has used benzoyl peroxide, salicylic acid, and topical antibiotics in the past but these treatments have had little effect. The patient would like to try minocycline, which worked for a friend of hers. The physician responds that this drug cannot be given to pregnant women, and offers to start the patient on the drug after she delivers the baby. Minocycline may be toxic to the fetus through which mechanism?

A 32-year-old pregnant woman presents to the clinic with complaints of cramping, abdominal pain, and severe watery diarrhea for the past 3 days. She also is nauseous and complains of fever and malaise. She was started on a 7-day course of amoxicillin after being admitted to the hospital for pyelonephritis 5 days ago. The vital signs include heart rate 98/min, respiratory rate 16/min, temperature 38.9°C (102.0°F), and blood pressure 92/56 mm Hg. Physical examination reveals abdominal distention with diffuse tenderness. Laboratory studies show a peripheral white blood cell (WBC) count of 15,000/mm3 and stool guaiac positive for occult blood. Which of the following is the best pharmacotherapy for her condition?

Five days after being admitted to the hospital for a scald wound, a 2-year-old boy is found to have a temperature of 40.2°C (104.4°F). He does not have difficulty breathing, cough, or painful urination. He initially presented one hour after spilling a pot of boiling water on his torso while his mother was cooking dinner. He was admitted for fluid resuscitation, nutritional support, pain management, and wound care, and he was progressing well until today. He has no other medical conditions. Other than analgesia during this hospital stay, he does not take any medications. He appears uncomfortable but not in acute distress. His pulse is 150/min, respirations are 41/min, and blood pressure is 90/50 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 99%. Examination shows uneven, asymmetrical scalding covering his anterior torso in arrow-like patterns with surrounding erythema and purulent discharge. The remainder of the examination shows no abnormalities. His hemoglobin is 13.4 g/dL, platelet count is 200,000/mm3, and leukocyte count is 13,900/mm3. Which of the following is the most appropriate initial pharmacological treatment for this patient?