Online database for Leptospira spp. launched
5 September 2008
Researchers studying Leptospira interrogans, the most common of the Leptospira species to cause leptospirosis in humans, can now unambiguously identify and access epidemiological information on the strain they are working on, thanks to the launch of a multilocus sequence typing (MLST) database for Leptospira ssp.
The database, which is free to access online, allows researchers to compare the sequence of a strain of L. interrogans with that of over 200 known isolates to discover if similar strains have been found previously. The information available for each isolate includes details on its geographical distribution, the date of isolation and host from which it was isolated.
Human leptospirosis is usually acquired following environmental exposure to Leptospira shed in the urine of an infected animal. It is an emerging disease worldwide, and is most commonly diagnosed during the rainy season in tropical regions. Infection causes an acute febrile illness that may include chills, headache, muscle pain, redness of the eyes and abdominal symptoms such as nausea, vomiting and diarrhoea. A minority of infections are severe (Weil’s disease) and may be fatal.
Over two-thirds of the isolates in the new database were collected from patients with leptospirosis in Thailand between 2000 and 2005, by a team of researchers including Dr Sharon Peacock, a Wellcome Trust Career Fellow in Clinical Tropical Medicine, together with Mrs Vanaporn Wuthiekanun, Dr Wirongrong Chierakul and colleagues from the Mahidol-Oxford Tropical Medicine Research Programme, Bangkok, Thailand.
Multilocus sequence typing (MLST) uses DNA sequence information from seven 'housekeeping genes' to unambiguously characterise different isolates of a given bacterial species. These housekeeping genes (generally those involved in metabolism) evolve much more slowly than some other bacterial genes (such as those that produce cell-surface proteins), and so are suitable for epidemiological studies.
Leptospira interrogans is the 25th organism to have a dedicated MLST database online at www.mlst.net, which was launched with the help of Dr David Aanensen. The Leptospira database will be curated by Dr Janjira Thaipadungpanit. MLST was developed in the laboratories of Martin Maiden, Dominique Caugant, Ian Feavers, Mark Achtman and Brian Spratt. The databases are hosted by Imperial College London and are funded by the Wellcome Trust.
Image: A scanning electron micrograph (SEM) showing a number of Leptospira bacteria on a polycarbonate filter; CDC/Rob Weyant
References
Thaipadungpanit J et al. Emergence of a virulent clone of Leptospira interrogans as the cause of an epidemic of human leptospirosis in Thailand. PLoS Negl Trop Dis 2007;1(1):e56.