Coxiella burnetii, bacterium, SEM

Coloured scanning electron micrograph (SEM) of Coxiella burnetii, gram-negative, rod, bacterium that causes Q fever. The outer cell membrane contains a lipopolysaccharide (LPS, endotoxin) which is important for the pathogenicity of the bacterium. Coxiella burnetii lives in domestic and wild animals (sheep, goats, cattle) and ticks. Bacteria are excreted in milk, urine, and faeces of infected animals. The bacteria are resistant to heat, drying, and many common disinfectants; thus the bacteria survive for long periods in the environment. Coxiella burnetii can be contracted by coming into contact with materials that have been contaminated by faeces and inhaled or ingested (zoonosis). It causes an influenza-like pneumonia (Q fever) but is usually not fatal. A complication of Q fever is chronic endocarditis. Magnification: x2,200 when shortest axis printed at 25 millimetres.