Research article

High resolution, on-line identification of strains from the Mycobacterium tuberculosis complex based on tandem repeat typing

Philippe Le Flèche^1,2 , Michel Fabre³ , France Denoeud² , Jean-Louis Koeck⁴ and Gilles Vergnaud^1,2

¹  Centre d'Etudes du Bouchet BP3, 91710 Vert le Petit, France

²  GPMS, Bât. 400, Institut de Génétique et Microbiologie, Université Paris Sud, 91405 Orsay cedex, France

³  Laboratoire de Biologie Clinique, HIA Percy, 92141 Clamart, France

⁴  Département de biologie médicale, HIA Val-de-Grâce, 75230 Paris, France

author email corresponding author email

BMC Microbiology 2002, 2:37doi:10.1186/1471-2180-2-37

Published:	27 November 2002

Abstract

Background

Currently available reference methods for the molecular epidemiology of the Mycobacterium tuberculosis complex either lack sensitivity or are still too tedious and slow for routine application. Recently, tandem repeat typing has emerged as a potential alternative. This report contributes to the development of tandem repeat typing for M. tuberculosis by summarising the existing data, developing additional markers, and setting up a freely accessible, fast, and easy to use, internet-based service for strain identification.

Results

A collection of 21 VNTRs incorporating 13 previously described loci and 8 newly evaluated markers was used to genotype 90 strains from the M. tuberculosis complex (M. tuberculosis (64 strains), M. bovis (9 strains including 4 BCG representatives), M. africanum (17 strains)). Eighty-four different genotypes are defined. Clustering analysis shows that the M. africanum strains fall into three main groups, one of which is closer to the M. tuberculosis strains, and an other one is closer to the M. bovis strains. The resulting data has been made freely accessible over the internet http://bacterial-genotyping.igmors.u-psud.fr/bnserver webcite to allow direct strain identification queries.

Conclusions

Tandem-repeat typing is a PCR-based assay which may prove to be a powerful complement to the existing epidemiological tools for the M. tuberculosis complex. The number of markers to type depends on the identification precision which is required, so that identification can be achieved quickly at low cost in terms of consumables, technical expertise and equipment.