Image source: http://www.theguardians.com/Microbiology/Coxiella_burnetii.png
Bacteria; Proteobacteria; Gammaproteobacteria; Legionellales; Coxiellaceae; Coxiella; Coxiella burnetii
Chromosome: 1,995,275 bp
Plasmid pSAP1: 94,287 bp
Coxiella burnetti is a gram-negative, non-sporing short, rod-like, non-motile, aerobic micro-organism that is the causal agent of Q fever, a zoonotic disease considered notifiable in the USA. This pathogen was discovered in 1937 in people working in a slaughter-house, in Queensland, Australia.
Coxiella are capable of inducing acute infections in humans resulting in isolated bouts of fever, pneumonia, granulomatous hepatitis (the most frequent form in France), abortion or meningoencephalitis.
Coxiella burnetti can induce abortion in domestic mammals (cat, dog, rabbit) and ruminants, and these animals represent their main reservoir. The danger posed by Coxiella is that they can be excreted by animals exhibiting no apparent clinical signs of the disease, whether following natural infection or because the animals have been vaccinated with an ineffective vaccine. This can then be tranported to humans via inhalation or tick bite.
There is uncertainty with regards to what the “Q” stands for: it may mean Queensland Fever since that it where the fever was first identified, or it may used to designate ‘unknown fever’, since Q is the equivalent of the French “X".
The bacterium has been difficult to study because it cannot be cultured on artificial media, and it grows slowly. The microbe replicates about every ten hours (compared to a half hour for E. coli ), which means it can take two weeks to grow enough for some experiments.
Coxiella burnetti is considered by the US government as a possible agent for bioterrorism as it is highly infectious and resistant to heat and drying. It can become airborne and inhaled by humans. A single Coxiella burnetii organism may cause disease in a susceptible person.
The Institute for Genomic Research, 9712 Medical Center Drive, Rockville, MD 20850, USA.
Seshadri R, Paulsen IT, Eisen JA, Read TD, Nelson KE, Nelson WC, Ward NL, Tettelin H, Davidsen TM, Beanan MJ, Deboy RT, Daugherty SC, Brinkac LM, Madupu R, Dodson RJ, Khouri HM, Lee KH, Carty HA, Scanlan D, Heinzen RA, Thompson HA, Samuel JE, Fraser CM, Heidelberg JF., Proceedings of the National Academy of Sciences of the United States of America 100(9):5455-60 (2003 Apr 29).