A 24-year-old woman comes to the emergency department due to fevers and chills over the last 24 hours. Three weeks ago, she underwent a partial bowel resection for Crohn disease without complications. Since the surgery, the patient has had difficulty eating and has a peripherally inserted central venous catheter in place through which she is receiving parenteral nutrition. Her temperature is 38.2 C (101 F), blood pressure is 100/60 mm Hg, and pulse is 114/min. The surgical wound healed well, and her abdomen is soft and nontender. The catheter site on the left arm is mildly tender but shows no erythema. Chest x-ray reveals a properly positioned central venous line and is otherwise unremarkable. Admission blood cultures subsequently return positive for yeast. Which of the following is characteristic of the most likely organism causing this bloodstream infection?

Question

A 24-year-old woman comes to the emergency department due to fevers and chills over the last 24 hours.  Three weeks ago, she underwent a partial bowel resection for Crohn disease without complications.  Since the surgery, the patient has had difficulty eating and has a peripherally inserted central venous catheter in place through which she is receiving parenteral nutrition.  Her temperature is 38.2 C (101 F), blood pressure is 100/60 mm Hg, and pulse is 114/min.  The surgical wound healed well, and her abdomen is soft and nontender.  The catheter site on the left arm is mildly tender but shows no erythema.  Chest x-ray reveals a properly positioned central venous line and is otherwise unremarkable.  Admission blood cultures subsequently return positive for yeast.  Which of the following is characteristic of the most likely organism causing this bloodstream infection?

Quizplus · Accepted Answer

11ec160b_3814_c7bf_9249_e94cb5e8059a_MD0001_00 This patient who has a central venous catheter and is receiving parenteral nutrition has sepsis (fever, tachycardia) with blood cultures growing yeast. Patients receiving parenteral nutrition (through a central venous catheter) are at high risk for candidemia (Candida in the bloodstream). Candida can colonize the catheter, and the lipid emulsion in the parenteral nutrition solution is thought to promote the growth of some Candida species. The morphology of Candida includes branching pseudohyphae with blastoconidia. Most species are susceptible to echinocandins, and C albicans is nearly always susceptible to fluconazole. (Choice A) Broad-based budding is characteristic of Blastomyces. This organism can cause pulmonary infection and occasional dissemination, but bloodstream infection in the setting of a vascular catheter is unlikely. (Choice B) Coccidioides is a dimorphic fungi endemic to the southwestern United States. This organism is inhaled and can cause pulmonary infection with occasional dissemination, particularly among immunocompromised patients. (Choice C) Cryptococcus is a yeast with a thick capsule that does not absorb India ink, resulting in a clear halo that can aid in the diagnosis of cryptococcal infection. The most common cryptococcal infection is meningitis, particularly among immunocompromised patients. Fungemia in the setting of a vascular catheter is uncommon. (Choice E) Right-angle branching hyphae are characteristic of mucormycosis, a mold infection primarily due to Mucorales or Rhizopus species. These infections can cause invasive disease in immunocompromised patients, including angioinvasive infections, but the organisms do not grow in blood cultures and are not associated with intravascular catheters. Educational objective: The presence of a central vascular catheter and receipt of parenteral nutrition are risk factors for candidemia. Candida display a morphology of branching pseudohyphae with blastoconidia. __________ References: British Society for Medical Mycology best practice recommendations for the diagnosis of serious fungal diseases. (http://www.ncbi.nlm.nih.gov/pubmed/25771341) Epidemiology of invasive mycoses in North America. (http://www.ncbi.nlm.nih.gov/pubmed/20088682)

A 24-Year-Old Woman Comes to the Emergency Department Due to Fevers