Infectious Diseases

During clinical rounds, the infectious disease service evaluates a 68-year-old male admitted with a two-week history of nocturnal sweats, generalized malaise, and a newly detected holosystolic murmur at the cardiac apex. Transesophageal echocardiography reveals a 1.4-cm mobile vegetation on the mitral valve along with moderate mitral regurgitation. The laboratory notifies the team that all four sets of blood cultures drawn upon admission are growing Enterococcus faecalis. The isolate demonstrates susceptibility to ampicillin, vancomycin, and daptomycin, but exhibits high-level resistance to gentamicin. Renal function is within normal limits. Which of the following is the most appropriate intravenous antibiotic regimen for this patient?

Zoonotic and vector-borne infections can present with diverse, overlapping systemic symptoms. Their management heavily depends on the specific pathogen, disease stage, and patient comorbidities. Based on the clinical features provided, which antimicrobial regimen is the most appropriate next step in management for each patient? Match each clinical scenario with its optimal targeted pharmacotherapy.

Match each patient's clinical scenario with the most appropriate antimicrobial management strategy, reflecting current infectious disease and antimicrobial stewardship guidelines.

A 42-year-old man presents to the emergency department with a 4-week history of a persistent productive cough, subjective low-grade fevers, drenching night sweats, and an unintentional 5-kg (11-lb) weight loss. He immigrated to the United States from Southeast Asia five years ago. His vital signs are temperature 38.1°C (100.6°F), blood pressure 118/76 mmHg, heart rate 92/min, and respiratory rate 18/min. A portable chest radiograph performed in the emergency department demonstrates a 3-cm cavitary lesion in the apical segment of the right upper lobe. The patient is currently resting in a standard emergency department examination room with the door closed.

Arrange the following interventions in the most appropriate chronological sequence for the comprehensive management of this patient.

For each of the following patients, select the most appropriate targeted antimicrobial therapy based on current clinical guidelines and stewardship principles.

A 42-year-old man is hospitalized for community-acquired pneumonia. On admission, he presented with a temperature of 38.9°C (102.0°F), a productive cough, and a right lower lobe infiltrate on chest radiograph. He was empirically started on intravenous ceftriaxone and azithromycin. On hospital day 3, his temperature is 37.1°C (98.8°F), blood pressure is 122/78 mm Hg, pulse is 78/min, and oxygen saturation is 97% on room air. He is tolerating a regular diet and states he is feeling much better. Sputum cultures collected on admission have grown Streptococcus pneumoniae. Susceptibility testing shows the isolate is sensitive to penicillin, amoxicillin, ceftriaxone, levofloxacin, and vancomycin. Which of the following is the most appropriate next step in management?

Emergency medical services bring an unresponsive 21-year-old university student to the emergency department. Her roommate reports she had been complaining of a severe headache, nausea, and photophobia for the past 24 hours. Vital signs show a temperature of 39.2°C (102.5°F), blood pressure of 90/60 mmHg, heart rate of 115/min, and respiratory rate of 22/min. Physical examination reveals marked nuchal rigidity and a diffuse non-blanching petechial rash on her lower extremities. Fundoscopic examination demonstrates bilateral papilledema.

Arrange the following diagnostic and therapeutic steps in the most appropriate chronological sequence for this patient's management.

A $71$-year-old man is evaluated on hospital day $3$ for ongoing management of acute pyelonephritis and concurrent bacteremia. At the time of admission, he presented with a temperature of $39.4^\circ\text{C}$ ($102.9^\circ\text{F}$), heart rate of $112 \text{ /min}$, and blood pressure of $88/54 \text{ mm Hg}$. Following aggressive fluid resuscitation, he was empirically started on intravenous ceftriaxone. He has demonstrated significant clinical improvement, currently reporting minimal flank pain. Today, his temperature is $37.5^\circ\text{C}$ ($99.5^\circ\text{F}$) and blood pressure is $122/78 \text{ mm Hg}$. Blood and urine cultures obtained prior to antibiotic initiation both demonstrate heavy growth of *Enterobacter cloacae*. The microbiology laboratory reports the following minimum inhibitory concentrations (MIC) and interpretations for the isolate:

Which of the following is the most appropriate next step in pharmacotherapy?

A 61-year-old female is evaluated in the hospital on day 4 of admission for a non-healing right foot ulcer. She has a 15-year history of type 2 diabetes mellitus complicated by severe peripheral neuropathy. On admission, she presented with localized erythema, warmth, and purulent drainage from a deep plantar ulcer. A probe-to-bone test was positive. She was hemodynamically stable with no signs of systemic inflammatory response syndrome. A deep bone biopsy was obtained for culture, and she was empirically started on intravenous vancomycin and piperacillin-tazobactam.

Today, her erythema has significantly improved. She remains afebrile and hemodynamically stable. The bone biopsy culture results are now available, demonstrating heavy growth of two organisms. Blood cultures show no growth.

The antimicrobial susceptibility report is as follows:

Based on these results, which of the following is the most appropriate next step in this patient's antimicrobial management?

A 68-year-old woman is brought to the emergency department by her daughter due to a high fever, severe diffuse headache, and progressive confusion over the past 24 hours. Her temperature is 39.2°C (102.6°F), blood pressure is 110/70 mm Hg, and heart rate is 115/min. She is lethargic but arouses to painful stimuli. Physical examination reveals marked nuchal rigidity. Ophthalmoscopic examination demonstrates bilateral blurring of the optic disc margins. Arrange the following steps in the most appropriate chronological order for the immediate management of this patient's condition.

Match each clinical presentation of an immunocompromised patient with the most appropriate primary pharmacotherapy for their underlying condition.

A 54-year-old woman is brought to the emergency department by her partner due to progressive confusion, a severe generalized headache, and fever for the past 14 hours. Her past medical history is significant for severe rheumatoid arthritis, for which she currently takes methotrexate and infliximab. Her temperature is $39.4^\circ\text{C}$ ($102.9^\circ\text{F}$), blood pressure is $105/65\text{ mmHg}$, pulse is $118/\text{min}$, and respiratory rate is $22/\text{min}$. On physical examination, she is lethargic but localizes to painful stimuli. She has marked nuchal rigidity and positive Kernig and Brudzinski signs. Fundoscopic examination reveals blurring of the bilateral optic disc margins.

Arrange the following management steps in the most appropriate chronological order for this patient.

During morning rounds on the hematology-oncology ward, a 45-year-old female patient is noted to have a temperature of $38.8^\circ C$ ($101.8^\circ F$). She was admitted two weeks ago for induction chemotherapy to treat acute myeloid leukemia. The patient reports moderate fatigue but denies any localizing symptoms such as cough, dysuria, abdominal pain, or skin changes. Vital signs show a blood pressure of $115/75$ mm Hg, a heart rate of $105$/min, and a respiratory rate of $16$/min. Physical examination demonstrates an indwelling central venous catheter with clean, non-erythematous margins and no tenderness to palpation. Her lungs are clear to auscultation, and her abdomen is soft and non-tender. Laboratory analysis reveals a leukocyte count of $400/\mu L$ with an absolute neutrophil count of $50/\mu L$. After drawing blood cultures from the catheter and a peripheral vein, which of the following is the most appropriate initial pharmacologic management?

During a visit to the student health clinic, a 20-year-old male describes a sudden onset of severe throat pain and subjective fever over the past 24 hours. He reports no cough or rhinorrhea. Vital signs reveal a temperature of 38.3°C (101.0°F). Physical examination demonstrates bilateral tonsillar erythema with purulent exudates and tender anterior cervical lymph nodes. A rapid antigen detection test for Group A Streptococcus is positive. Which of the following is the most appropriate antimicrobial regimen for this patient?

Match each clinical scenario involving a potential infectious exposure with the most appropriate post-exposure prophylaxis (PEP) or management strategy.

Match each classic infectious disease clinical presentation with its most appropriate first-line antimicrobial therapy.

An emergency medicine physician evaluates a 45-year-old immigrant male who complains of a 6-week history of productive cough, intermittent hemoptysis, drenching night sweats, and unintentional weight loss. The triage nurse notes a temperature of 38.2°C (100.8°F). The patient hands the physician a chest radiograph taken earlier today at an urgent care center, which reveals a prominent cavitary lesion in the right upper lobe. Arrange the following management steps in the most appropriate chronological order for this patient.

A 42-year-old man presents to the clinic with a 2-day history of a progressively spreading red, swollen, and tender area on his right lower extremity. He recalls scratching a mosquito bite in the same location a few days prior. He has no significant past medical history and takes no medications. Vital signs are temperature 37.3°C (99.1°F), blood pressure 124/76 mmHg, pulse 82/min, and respirations 14/min. Physical examination reveals a 10-cm area of diffuse erythema, warmth, and induration on the right shin. The borders of the erythema are indistinct. There is no palpable fluctuance, purulent drainage, ulceration, or crepitus. Peripheral pulses and distal sensation are intact. Which of the following is the most appropriate empiric pharmacotherapy for this patient?

A 26-year-old woman comes to the clinic reporting a 3-day history of a burning sensation with urination and increased urinary frequency. She has no fever, chills, flank pain, nausea, or vaginal discharge. Her temperature is $37.1^\circ C$ ($98.8^\circ F$), blood pressure is $118/76$ mm Hg, and pulse is $74$/min. Physical examination reveals mild suprapubic tenderness but no costovertebral angle tenderness. A urine dipstick test is positive for nitrites and leukocyte esterase. A urine pregnancy test is negative. Which of the following is the most appropriate empiric pharmacotherapy for this patient?

A 24-year-old primigravida at $18$ weeks gestation presents to the obstetric clinic with a painless, indurated ulcer on her right labium majus that appeared one week ago. She has bilateral inguinal lymphadenopathy. Rapid plasma reagin (RPR) testing is reactive at a titer of $1:32$, and fluorescent treponemal antibody absorption (FTA-ABS) testing is positive. The patient reports a well-documented history of anaphylaxis to amoxicillin in childhood, characterized by severe wheezing, facial swelling, and hypotension requiring epinephrine. She is otherwise healthy and takes a daily prenatal vitamin. Vital signs are within normal limits, and fetal heart tones are $145$/min.

Arrange the following interventions in the most appropriate chronological sequence for the management of this patient's infectious disease.