Which of the following microorganisms is most likely to cause a life-threatening infection in a patient admitted with diabetic ketoacidosis?

• A. Staphylococcus epidermidis
• B. Rhizopus species (a type of Mucorales fungus)
• C. Escherichia coli
• D. Candida albicans

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the clinical context—diabetic ketoacidosis (DKA) is a condition that predisposes patients to certain infections due to high blood sugar, acidic blood pH, and impaired immune function.
2. Step 2: Review the characteristics of each microorganism listed: Staphylococcus epidermidis is usually a skin commensal and less likely to cause severe infections in DKA; Escherichia coli is a common cause of urinary and bloodstream infections but not specifically linked to DKA-related life-threatening infections; Candida albicans is a fungal pathogen causing opportunistic infections but typically not the most aggressive in DKA.
3. Step 3: Recognize that Rhizopus species, a member of the Mucorales order, is known to cause mucormycosis, a rapidly progressing and life-threatening fungal infection especially in patients with DKA due to their impaired ability to handle iron and acidic environment favoring fungal growth.
4. Step 4: Connect the pathophysiology of DKA with the susceptibility to mucormycosis by understanding that elevated free iron in acidic conditions promotes Rhizopus growth, making it the most likely cause of a life-threatening infection in this scenario.
5. Step 5: Conclude that among the options, Rhizopus species is the microorganism most likely to cause a life-threatening infection in a patient admitted with diabetic ketoacidosis.