• Brucellosis is a chronic granulomatous zoonotic infection transmitted to humans though infected animals, consumption of raw meat or unpasteurized dairy products, or by inhalation. Brucella species most frequently causing infections are B. melitensis (sheep and goats), B. abortus (cattle), B. suis (pigs), and, rarely, B. canis (dog). The disease occurs in shepherds, abattoir workers, veterinarians, and dairy industry professionals.
• Brucellosis is one of the most common infections that can be acquired in microbiology laboratories though routine workup of cultures outside of biologic safety cabinets (BSCs). Procedures that place microbiologists at high risk of contracting the infection include aerosol-generating procedures, such as vortexing, centrifuging, mouth pipetting, catalase testing, or sniffing culture plates.
• Brucella-exposed individuals that are classified as high risk are advised to receive postexposure prophylaxis, which consists of a regimen of doxycycline and rifampin for 21 days. The 2012 postexposure recommendations for frequency of serologic testing at the Centers for Disease Control and Prevention (CDC) on all workers exposed to Brucella include at baseline and at 6, 12, 18, and 24 weeks postexposure.
• Symptom surveillance of postexposure events includes daily fever checks for febrile illness and symptom watch over a 24-week period after the last known exposure.
• Slow-growing coccobacillary gram-negative rods can be considered presumptive Brucella species when the patient history and symptoms, particularly when coupled with travel to an endemic area, are consistent with brucellosis. An isolate can be considered as presumptive Brucella when there is slow, scant growth on chocolate and blood agar and no growth on MacConkey agar.
• Suspicious Brucella isolates test positive for oxidase, urease, and catalase, and these procedures must be performed in a BSC. Timely notification of the clinician and public health officials is mandated when a Brucella isolate is suspected. Automated identification systems must not be used with when Brucella is suspected. Polymerase chain reaction (PCR) technology for identification at the species level is available at public health laboratories.
