A veterinary doctor had pyrexia of unknown origin. His blood culture in special laboratory media was positive for gram-negative sho bacilli which was oxidase positive. Which one of the following is the likely organism grown in culture?

Ans. (d) Brucella spp Oxidase positive gram-negative organism producing pyrexia of unknown origin in veterinary doctor is pointing towards Brucella (coccobacilli or sho rods). Brucella is the causative agent of Brucellosis (Malta fever, undulant fever). Other options: Pasturella spp. (P. multocida) It is also sho bacilli and oxidase positive, but it can grow over normal media and does not present with pyrexia of unknown origin. It is nonmotile and produces indole. Manifestation of pasturella: Local suppuration, Meningitis, Respiratory tract infection. Francisella (Casuative agent of Tularemia): It is also sho bacilli with fastidious growth requirement. But it is oxidase negative. Remember: Brucella is oxidase and catalase positive except B. neotomae and B. ovis. Risk factors for Brucellosis (Zoonotic disease). Occupational--Farmers, shepherds, Veterinarians, Goats herds, Slaughter-house workers. Domestic--family members of individual in animal husbandry. Laboratory workers--involved in handing cultures. Travellers and Urban dwellers. Brucella can grow over normal media but growth is improved by addition of serum or liver extract.