All of the following statements regarding melioidosis are true, EXCEPT:: (A) It is caused by Burkholderia mallei, (B) It is caused by a gram negative aerobic bacteria, (C) Etiologic agent shows bipolar staining with methylene blue stain, (D) Pulmonary infection is the most common form of melioidosis
Answer is A. Melioidosis is caused by Burkholderia Pseudomallei. It is a free living small motile aerobic gram negative bacillary saprophyte normally found in soily ponds & rice paddies. Humans and animals are infected by inoculation, inhalation, or ingestion. It grows at 42 degree C & oxidize glucose, lactose & is oxidase positive. It is a facultative intracellular organism which replicates in neutrophils and macrophages with the help of a polysaccharide capsule. The organism also possesses elements of a type III secretion system that plays a role in its intracellular survival. Gram's stain of a specimen shows a small gram negative bacilli. Wright's stain or methylene blue staining shows a bipolar regularly staining (safety pin appearance). Positive culture is diagnostic. Ref: Harrisson's Principles of Internal Medicine, 18th Edition, Chapter 152