Klebsiella pneumoniae bacterium. Coloured scanning electron micrograph (SEM) of a Klebsiella pneumoniae bacterium in a mouse lung. It is caught in a neutrophil extracellular trap (NET, green), a web of extruded chromatin that contains antimicrobial components that kill the bacterium. Neutrophils are the most abundant cell of the immune system. Klebsiella pneumonia is a Gram-negative, rod-shaped (bacillus) bacterium that is part of the normal flora of the skin and intestines. However, in those w
The genus Klebsiella belongs to the tribe Klebsiellae, a member of the family Enterobacteriaceae. The organisms are named after Edwin Klebs, a 19th century German microbiologist. Klebsiellae are nonmotile, rod-shaped, gram-negative bacteria with a prominent polysaccharide capsule. This capsule encases the entire cell surface, accounts for the large appearance of the organism on gram stain, and provides resistance against many host defense mechanisms.