European Society of Mycobacteriology - Instituto Nacional de Saúde ...

PP-2
68 SPACERS Mycobacterium tuberculosis COMPLEX SPOLIGOTYPING :
A STUDY USING A MICROBEAD-BASED HIGH THROUGHPUT FORMAT.
Zhang J 1 , Abadia E 1 , Refrégier G 1 , Ruimy R 2 , Boschiroli ML 3 , Guillard B 4 and C. Sola 1 .
1 - Institut de Génétique et Microbiologie, UMR8621, CNRS-Université Paris-Sud (Universud), Equipe IGEPE, bât. 400,
Centre scientifique d’Orsay, rue Gregor Mendel, 91405 Orsay-Cedex2 - APHP, Hôpital Bichat-Claude Bernard, Paris
3 - Agence française de sécurité sanitaire des aliments AFSSA, Maisons-Alfort
4 - Institut Pasteur du Cambodge
New captures probes for the microbead-based spoligotyping assay (Luminex) were designed to test for the presence/
absence of 25 spacers that are not used in routine spoligotyping. These spacers are expected to provide an improved
discriminatory power for Major Genetic Group I, including the « ancestral » TbD1+ MTC (Mycobacterium tuberculosis
complex) clinical isolates.
The new 68 spacers spoligotyping format developed on a Luminex platform was shown to give excellent results. Around
400 strains of MTC from 3 different centers (Bichat Hospital, AFSSA, Institut Pasteur of Cambodia) were studied. We
show that the 68 spacers format is more discriminant to study the strains of the East African Indian family (EAI) : among
86 strains of the EAI family, it could distinguish 44 clusters compared to 27 clusters by routine 43 spacers spoligotyping.
Whereas for a total of 210 clinical isolates of Mycobacterium bovis, we reported 31 types instead of 25, and for a total
of 30 “Beijing” clinical isolates, 4 clusters instead of 3 clusters were found. For Mycobacterium africanum, a total of 17
strains were assayed and 11 instead of 9 clusters were found. High-thr(East-African Indian - Indo-Oceanic clade) and
other Major Genetic Group I still-undefined spoligotyping signatures. This observation often concerns the first spacer
of a string of several missing spacers (border domains). These observations are currently under further investigation by
sequencing. Extended High-throughput spoligotyping is also a new mean to detect mutational events that could be diagnostics
of clade-specific MTC evolution.
76 ESM 2009