Case Presentation: A 66-year-old Caucasian man presented to his primary care physician with significant fatigue and night sweats associated with 30-pound weight loss, headaches, and dyspnea on exertion. He reported the onset of symptoms one week after returning from a hunting trip in Georgia where he caught and cleaned wild boar. After this initial outpatient visit in which his beta blocker dose was decreased and two separate emergency room visits, he was admitted to our hospital for fever of unknown origin. Aside from fever of 102.9 F and appearing fatigued, his physical exam was unremarkable with hemodynamic stability. Admission labs were fairly normal except for sodium of 130, WBC of 4.07, elevated inflammatory markers and an elevated protein gap. A full infectious work up ensued and he was started on doxycycline empirically. Malignancy, autoimmune, vasculitis, peripheral blood smears, and extensive imaging workup were unrevealing. During the early part of admission, the patient was persistently febrile, prompting broadening antibiotics to include IV vancomycin and ampicillin/sulbactam. Initial blood cultures and gram stain reports revealed bacteria resembling gram positive rods and possible anaerobes. However, seven days after collection these were identified as Brucella suis, a gram-negative coccobacillus from feral pigs. Antibiotics were narrowed to six weeks PO doxycycline and two weeks IM streptomycin with complete resolution of his symptoms.
Discussion: Brucella is a slow growing microorganism and frequently misidentified on gram stain. Despite being a gram-negative bacteria, it frequently appears as gram positive versus gram variable. Even advanced laboratory analysis techniques such as Matrix-assisted laser desorption/ionization time of flight (MALDI-TOF), which uses proteomics to identify isolates, frequently have trouble identifying the isolate correctly. In addition to identification woes, Brucella aerosolizes in the lab and frequently leads to laboratory-acquired infections, necessitating prophylactic antibiotics and serial monitoring of exposed lab technicians. In order to diagnose brucellosis more expediently and to improve lab technician safety, a clinician must have a high level of suspicion and relay their concerns to the lab promptly. This is undoubtedly challenging given the rarity of the disease and the nonspecific signs and symptoms of brucellosis.
Conclusions: Brucella is (1) one of the many rare causes of fever of unknown origin, (2) often a delayed diagnosis in part due to lack of clinician’s awareness and (3) is frequently misidentified in the laboratory leading to many laboratory-acquired infections. Lastly, this case exemplifies that even with today’s advancements in imaging and technology, oftentimes a clinician’s best tool is the ability to take a good history.