細菌学および寄生虫学ジャーナル

概要

Molecular Approaches in the Detection and Characterization of Leptospira

Ahmed Ahmed, Martin P. Grobusch, Paul R. Klatser and Rudy A. Hartskeerl

Conventional diagnosis of leptospirosis and characterization of Leptospira spp. relies mainly on serology. A major drawback of serology in diagnosis is that it needs sufficient levels of anti-Leptospira antibodies, thus jeopardizing confirmation in the early acute phase of disease. The cross agglutinin absorption test (CAAT) that determines Leptospira serovars is a technically demanding and laborious method and therefore is only performed at a few laboratories. Novel molecular diagnostic tests mainly rely on the polymerase chain reaction (PCR). PCR perfectly complements serological testing, since it is especially sensitive in the first 5 days after onset of symptoms. Real time PCR is rapid and has been validated for their high clinical accuracy. The introduction of molecular techniques for defining Leptospira species revolutionized the categorization of strains in this genus, as species and serogroups appeared to show little correlation. The reference test in molecular speciation is based on determining DNA homology. This approach is tedious and user-unfriendly and therefore is increasingly replaced by other techniques. To date, a wealth of molecular typing methods is available. Most attractive are those techniques that provide direct digital and electronically portable data. Such techniques comprise fluorescent amplified fragment length polymorphism (FAFLP), array typing, multilocus variable number of tandem repeats analysis (MLVA) and sequence-based phylogeny, and to some extent pulsed field gel electrophoresis (PFGE). Multilocus sequence typing (MLST) is the most robust method for determining Leptospira strain diversity and in the future will probably only be surpassed by phylogeny on whole genome sequences.