Gram-negative Enteric Bacteria — Practice

A 28-year-old laboratory technician handling cultures develops fever, cough and a maculopapular rash. The implicated organism is one of the most infectious bacteria known (inoculum <10 organisms), is an obligate intracellular Gram-negative coccobacillus, and uniquely does NOT require an arthropod vector for human transmission, spreading instead by aerosol from parturient livestock. Which is the most likely agent?