A 25-year-old woman with sickle cell disease presents with fever, localized pain, and swelling over the right tibia. Blood culture grows a gram-negative rod that is non-lactose fermenting and produces H2S on TSI agar. Which organism is most likely responsible?

• A Proteus mirabilis
• B Escherichia coli
• C Pseudomonas aeruginosa
• D Salmonella enterica ✓

Explanation

Salmonella is the most common cause of osteomyelitis in patients with sickle cell disease due to infarcted bowel seeding the bloodstream and subsequent localization to infarcted bone. The description of a non-lactose fermenting, H2S-producing gram-negative rod points to Salmonella. E. coli is lactose fermenter. Pseudomonas is non-lactose fermenter but H2S-negative.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.