In suspected cases of brucellosis, what is the most sensitive specimen to submit for culture?

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

Answer: (A)

Brucella is an intracellular organism that concentrates in the reticuloendothelial system, so the bone marrow often harbors a higher bacterial load than other sites. This makes bone marrow culture the most sensitive option for detecting Brucella in suspected brucellosis; it often yields the organism even when cultures from other sites fail.

Nasopharyngeal swabs, sputum, and stool are not reliable sources for Brucella culture because the organism is not typically present in high numbers in those specimens, except in specific contexts like pulmonary involvement for sputum, which does not generally offer the best overall sensitivity.