A 12-year-old boy with sickle cell disease presents with pain and swelling of the right lower extremity. A bone scan reveals osteomyelitis of the tibial diaphysis. An organism found more commonly than in the general population in these cases is:

Although S. aureus is the most common organism found in osteomyelitis associated with sickle-cell disease, nontyphoid salmonella species are often found. Salmonella bacteria are thought to escape from the colonized colon due to microvascular infarcts secondary to sickle-cell disease. They then seed the bone via hematogenous spread.