What class of bacteria is most commonly associated with osteomyelitis in patients with sickle cell disease?

In patients with sickle cell disease, osteomyelitis is frequently associated with Gram-positive cocci, particularly Staphylococcus aureus, including Methicillin-resistant Staphylococcus aureus (MRSA). This association arises primarily due to the impaired immune response and splenic dysfunction commonly seen in individuals with sickle cell disease, which makes them more susceptible to infections.

The underlying pathophysiology involves the increased risk of avascular necrosis of the bone, bone infarction, and subsequent infection, which often involves these organisms. The lack of a properly functioning spleen, which normally filters bacteria and helps in the immune response, further predisposes these patients to infections by encapsulated organisms and opportunistic pathogens.

While other bacteria can cause osteomyelitis, they are less common in the context of sickle cell disease. Gram-negative rods can sometimes be involved, especially in certain scenarios or in the presence of other predisposing factors, but the predominant cause in this specific population remains Gram-positive cocci.