Case of the Month - October 2019 Case of the month archive A 32-year-old woman with no significant medical history went to the Emergency Room with one week of headaches, fevers, fatigue and night sweats. She had no nausea, diarrhea, abdominal pain, cough, or shortness of breath. During the previous three months she had been to Mexico, the Pocono Mountains in Pennsylvania, and the Bronx Zoo. She did not drink raw milk, or eat unpasteurized cheeses or raw meat. Physical exam was normal except for fever. Routine bloods were drawn. When the initial blood results came back as normal, she was sent home with a presumed diagnosis of viral infection. She was called back three days later when two blood culture sets turned positive. Gram stain demonstrated tiny Gram-positive coccobacilli. The organism grew on both blood and chocolate agar, but not on MacConkey agar. They were pinpoint at 24 hours, but easily visible as white, non-hemolytic colonies at 48 hours, and were oxidase, catalase, and urease positive. What is it? Figure 1: Gram-positive coccobacilli (Gram stain from blood culture at 72 hours). Figure 2: small white non-homolytic colonies after 48 hours of incubation on blood agar.