In suspected brucellosis, which specimen is most sensitive for culture?

• A. Bone marrow
• B. Nasopharyngeal swab
• C. Sputum
• D. Stool

Answer: (A)

Brucella organisms preferentially localize in reticuloendothelial tissues, so the bone marrow often harbors a high bacterial load. Because of this, bone marrow aspirate yields the highest chance of recovering Brucella on culture, even when blood cultures are negative or only intermittently positive. Nasopharyngeal swabs, sputum, and stool are not reliable sources for Brucella culture since the organism is not typically present in high numbers in those sites. Thus, bone marrow culture provides the greatest sensitivity for isolating Brucella in suspected brucellosis.