29th Annual Congress of European Society of Mycobacteriology

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Health Surveillance Centre (VISAVET). Complutense University

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29th Annual Congress of European Society of Mycobacteriology

VISAVET function: participant

Organizer: European Society of Mycobacteriology (ESM).

City: Plovdiv

Country: Bulgary

Date: July 6th-9th, 2008

Abstract book


Investigate mechanisms for variability in Mycobacterium avium subsp. paratuberculosis
Methods: A 60mer oligonucleotide microarray (MAPAC) covering both genomes of Mycobacterium avium subspecies paratuberculosis (MAP) and Mycobacterium avium subspecies avium strain 104 was used to perform comparative genomic studies on a panel of MAP isolates with variant morphologies isolated from a variety of hosts.
Results: The MAPAC microarray was able to define a set of large sequence
polymorphisms (LSPís) diagnostic for each of the three major 84 European Society of Mycobacteriology types of MAP and deleted LSPís associated with attenuation in MAP vaccine strains.
In addition, some strains contained up to 17 genomic regions (VSPís) giving signals suggestive of a series of large genomic regional duplications. VSPís were predominantly subsets of LSPís, with significantly low GC% regions and immediately flanked by insertion sequences or integrases. VSPís were present in only a proportion of any one culture. Confirmation of MAPAC differential signal increases was made using quantitative PCR of a selection of genes within VSPís (including several
virulence determinants and the rrn operon). Associations could be made between VSP duplications and colony growth rate / morphology. An increase in expression of transposase associated with VSPís and active transposition resulting in significant alteration of the MAP proteome was demonstrated after infection into a human macrophage cell line.
Conclusion: The control of transposase activity, possibly associated with host
cell entry, may be a mechanism for variation in genome plasticity and
phenotype switching in MAP

European Society of Mycobacteriology

29th Annual Congress of European Society of Mycobacteriology