tuberculosis in the index patient (total study period, 4 weeks). We carefully reviewed the batch number of each of these
isolates in order to pinpoint the day on which clinical specimens were handled for setting in culture, as well as any epidemiological 3-MA molecular weight links between patients. Multispacer sequence typing Isolates were identified using conventional methods [24] and, after proper inactivation [23], by sequencing of the ETR-D spacer, as previously described [18]. The MST genotyping, PCR amplification and sequence analysis of eight intergenic spacers were performed as described previously [17]. Two negative controls check details consisting of the PCR mix in the absence of the target DNA template were also performed. Purified PCR products were sequenced by use of the BigDye Terminator 1.1 Cycle Sequencing kit (Applied Biosystems, Courtaboeuf, France). Sequencing electrophoresis was performed using a 3130 Genetic Analyser (Applied Biosystems). Sequences were aligned using CLUSTAL W http://pbil.ibcp.fr and compared to each other and with a local database of M. tuberculosis spacer sequences that is freely available on our website http://ifr48.timone.univ-mrs.fr/MST_Mtuberculosis/mst. This study was approved by the local Ethics Committee, Marseille, France. Acknowledgements
The authors would like to acknowledge the technical expertise of Christian Fontaine. This study was supported by Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, Marseille, France and Œuvre Anti-tuberculeuse des Bouches du Rhône, Marseille, France.
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