A 42-year-old dairy farm worker presents with intermittent fever, night sweats, back pain, and weight loss over several weeks. Blood culture is performed in a biosafety cabinet due to aerosol risk. BAP shows small, smooth, convex colonies after 6 days; CHOC shows enhanced growth; Gram stain shows small GNB; Oxidase and Catalase tests are positive; Urea is pink within 2 hours. Which organism is suspected?

Prepare for the CAMLPR Microbiology Test. Utilize flashcards and engaging multiple-choice questions, each equipped with descriptions and explanations. Ready yourself for an excellent performance!

Brucellosis from livestock exposure is being tested here. The story fits brucellosis: a dairy farm worker with systemic illness—fever, night sweats, weight loss, and back pain—consistent with dissemination to bone or joints. The lab clues reinforce Brucella: gram-negative coccobacilli that are oxidase- and catalase-positive, with rapid urease activity turning urea pink within a couple of hours. Growth is slow but occurs on routine media like blood and chocolate agar, producing small, smooth, convex colonies that become more evident after several days; chocolate agar often enhances growth. The need for biosafety precautions due to aerosol risk also matches Brucella, a pathogen known for posing inhalation risk in the lab. The species context points to Brucella abortus, which is associated with cattle and dairy settings; Brucella suis would be more typical with swine exposure. Other organisms listed would not fit the combination of cattle exposure, the specific growth and biochemical profile, and the clinical presentation as well.