Infectious Diseases

A variety of patients present to the clinic and emergency department seeking care after high-risk infectious exposures. Match each clinical exposure scenario to the most appropriate post-exposure prophylaxis or preventive intervention.

Match each clinical presentation in a patient with advanced HIV infection to the most likely central nervous system etiology.

Match each clinical presentation of a zoonotic or vector-borne infectious disease with the most appropriate targeted antimicrobial therapy.

Match each clinical presentation of pneumonia or febrile respiratory illness to its most likely causative pathogen based on the provided epidemiological clues and distinct clinical findings.

During morning rounds in the intensive care unit, the medical team evaluates a patient recovering from a catheter-associated bloodstream infection. Empiric therapy with intravenous vancomycin and cefepime was initiated three days ago for suspected sepsis. The patient is currently afebrile and hemodynamically stable, and the offending central venous catheter has been removed. Final blood culture results from admission now reveal growth of *Enterococcus faecalis* in two out of two sets. The isolate demonstrates susceptibility to ampicillin, vancomycin, linezolid, and daptomycin. Which of the following is the most appropriate modification to this patient's antimicrobial regimen?

A $68$-year-old man is hospitalized due to a $4$-week history of fatigue, intermittent fevers, and unintentional weight loss. Two months ago, he underwent a cystoscopy for evaluation of hematuria. His temperature is $38.2^\circ\text{C}$ ($100.8^\circ\text{F}$), pulse is $92/\text{min}$, and blood pressure is $118/74\text{ mm Hg}$. Physical examination reveals small, linear, dark red streaks in the nail beds of both hands and a new grade $3/6$ holosystolic murmur heard best at the cardiac apex.

Echocardiography demonstrates a $1.2\text{-cm}$ mobile vegetation on the mitral valve with moderate mitral regurgitation.

Laboratory studies show:
Leukocyte count: $14,500/\text{mm}^3$
Serum creatinine: $2.2\text{ mg/dL}$ (baseline: $1.0\text{ mg/dL}$)

Three sets of blood cultures are drawn, and the patient is started empirically on intravenous vancomycin and piperacillin-tazobactam. Forty-eight hours later, all blood culture bottles grow *Enterococcus faecalis*. Susceptibility testing reveals:

Ampicillin: Susceptible
Vancomycin: Susceptible
Piperacillin-tazobactam: Susceptible
Gentamicin: High-level resistance

Which of the following is the most appropriate targeted pharmacotherapy for this patient?

A 52-year-old woman is hospitalized for induction chemotherapy for acute myeloid leukemia. On hospital day 12, she develops a new-onset fever of $38.7^\circ\text{C}$ ($101.7^\circ\text{F}$). Her blood pressure is 118/74 mm Hg, pulse is 98/min, and respirations are 16/min. Physical examination reveals no focal source of infection, and the exit site of her right internal jugular central venous catheter is clean without erythema or induration. Laboratory studies show an absolute neutrophil count of $150/\text{mm}^3$. She is hemodynamically stable and appears fatigued.

Arrange the following steps in the most appropriate chronological sequence for the management of this patient's neutropenic fever.

A 64-year-old female patient is currently hospitalized for the treatment of acute pyelonephritis. She initially presented to the emergency department three days ago with severe right-sided flank pain, dysuria, and a temperature of $39.2^\circ\text{C}$ ($102.6^\circ\text{F}$). Blood cultures were drawn, and empiric intravenous ceftriaxone was initiated. The admission blood cultures show no growth to date. However, the urine culture obtained prior to antibiotic administration has grown $>10^5$ colony-forming units/mL of *Escherichia coli*. The susceptibility report is as follows:

Today, the patient reports that her flank pain has nearly resolved. Her current temperature is $37.1^\circ\text{C}$ ($98.8^\circ\text{F}$), blood pressure is $122/78 \text{ mmHg}$, and heart rate is $78/\text{min}$. She is tolerating a regular diet without nausea.

Based on the culture results and the patient's clinical progress, which of the following is the most appropriate next step in the pharmacologic management of this patient?

Match each clinical infectious disease vignette with its most appropriate targeted pharmacotherapy or first-line treatment regimen.

For each of the following hospitalized patients presenting with severe, confirmed, or highly suspected infections, select the most appropriate definitive or targeted empiric intravenous antimicrobial therapy from the options provided.

Match each patient's clinical presentation with the most appropriate targeted antimicrobial therapy.

During morning rounds, a 52-year-old woman reports feeling chilled and fatigued. She is currently hospitalized on day 10 of induction chemotherapy for acute promyelocytic leukemia. Her temperature is $38.7^\circ\text{C}$ ($101.7^\circ\text{F}$), blood pressure is $122/76$ mmHg, heart rate is $94$/min, and respiratory rate is $16$/min. Pulse oximetry shows $98\%$ on room air. Physical examination reveals a right subclavian central venous port with a clean, dry, and intact dressing; there is no erythema, fluctuance, or tenderness around the site. The remainder of the examination, including thorough skin and mucosal evaluation, is unremarkable. Laboratory studies show a leukocyte count of $600/\text{mm}^3$ and an absolute neutrophil count of $120/\text{mm}^3$. Blood cultures are drawn from the central port and a peripheral vein. Which of the following is the most appropriate next step in pharmacotherapy?

A 54-year-old man with a history of end-stage renal disease on hemodialysis is currently hospitalized for management of suspected endocarditis. He presented three days ago with a two-week history of fatigue, severe night sweats, and intermittent fevers. His hemodialysis is accessed via a right internal jugular tunneled catheter. Vital signs today show a temperature of $39.4^\circ\text{C}$ ($102.9^\circ\text{F}$), blood pressure of $108/64\text{ mm Hg}$, pulse of $115/\text{min}$, and respiratory rate of $16/\text{min}$. Cardiac auscultation reveals a new high-pitched, blowing early diastolic murmur heard best at the left sternal border. Transesophageal echocardiography reveals a $1.5\text{-cm}$ oscillating vegetation on the aortic valve with severe aortic regurgitation. At the time of admission, empiric intravenous vancomycin and cefepime were initiated. Blood cultures drawn before the first antibiotic dose are now growing *Staphylococcus aureus*. The isolate is sensitive to oxacillin, cefazolin, and vancomycin, but resistant to penicillin. Which of the following is the most appropriate next step in the pharmacologic management of this patient?

A $64$-year-old man is admitted to the hospital with a $2$-week history of progressively worsening mid-back pain and low-grade fevers. He has a history of poorly controlled type 2 diabetes mellitus. His temperature is $38.2^\circ\text{C}$ ($100.8^\circ\text{F}$), blood pressure is $128/78\text{ mmHg}$, and pulse is $92\text{/min}$. Physical examination reveals point tenderness over the $T10-T11$ spinous processes. Neurologic examination of the lower extremities is completely normal. Laboratory studies show an erythrocyte sedimentation rate (ESR) of $85\text{ mm/h}$ and a C-reactive protein (CRP) level of $112\text{ mg/L}$. Magnetic resonance imaging (MRI) of the thoracic spine demonstrates abnormal marrow signal and enhancement of the $T10$ and $T11$ vertebral bodies with a small adjacent fluid collection, diagnostic of vertebral osteomyelitis. Two sets of blood cultures are obtained, and the patient is started on empiric intravenous vancomycin and piperacillin-tazobactam. On hospital day $3$, the patient's temperature is $37.4^\circ\text{C}$ ($99.3^\circ\text{F}$). Both sets of blood cultures are positive for Staphylococcus aureus that is susceptible to oxacillin, cefazolin, and vancomycin, but resistant to penicillin. Which of the following is the most appropriate next step in the pharmacologic management of this patient?

Match each HIV-positive patient's clinical presentation and neuroimaging or cerebrospinal fluid (CSF) finding with the most likely causative pathogen or etiology.

Match each patient's clinical presentation with the most appropriate initial or definitive targeted pharmacotherapy.

A 28-year-old surgical resident sustains a deep, bleeding puncture wound to her left index finger from a hollow-bore needle immediately after drawing arterial blood. The source patient is known to be HIV-positive with a high viral load and is concurrently infected with hepatitis C. The resident has previously received the complete hepatitis B vaccine series and has a documented positive surface antibody titer. Arrange the following steps in the most appropriate chronological order for managing this healthcare worker's occupational exposure.

Match each clinical presentation of a suspected or confirmed systemic fungal infection with its most appropriate first-line targeted therapy or initial empiric management strategy.

A 74-year-old man residing in a skilled nursing facility is evaluated on hospital day $3$ for a complicated urinary tract infection. He was initially brought to the emergency department for altered mental status and a new fever. On admission, his temperature was $38.9^\circ\text{C}$ ($102.0^\circ\text{F}$), and his long-term indwelling urinary catheter was found to be obstructed with purulent sediment. The catheter was promptly removed, and he was started empirically on intravenous vancomycin and piperacillin-tazobactam. Today, the patient is afebrile, his mental status has returned to baseline, and he is tolerating an oral diet. Blood cultures obtained on admission show no growth. A urine culture obtained via straight catheterization prior to antibiotic initiation grows $>100,000\text{ CFU/mL}$ of Escherichia coli. Susceptibility testing reveals the organism is susceptible to ceftriaxone, ciprofloxacin, and trimethoprim-sulfamethoxazole, but resistant to ampicillin. Which of the following is the most appropriate next step in management?

A 68-year-old man is brought to the emergency department by his family due to confusion, a severe headache, and high fever that began 24 hours ago. He has a history of type 2 diabetes mellitus and hypertension. His temperature is 39.2°C (102.6°F), blood pressure is 112/74 mm Hg, heart rate is 115/min, and respiratory rate is 22/min. Physical examination shows marked nuchal rigidity. Neurologic examination reveals lethargy and a mild left-sided hemiparesis. The physician suspects bacterial meningitis. Arrange the following management steps in the most appropriate chronological order for this patient.