Poster communication in 31st Annual Congress of the European Society of Mycobacteriology (ESM 2010)

July 4^th, 2010

Castellanos E., de Juan L., Rodriguez-Campos S., Alvarez J., Alende T., Gutierrez A., Mateos A., Aranaz A. and Dominguez L.

Mycobacterium avium subspecies paratuberculosis is a world-wide microorganism that causes paratuberculosis or Johne’s disease in many animal species, mainly ruminants. The role of this agent in the development of Crohn’s disease in humans has been discussed although this hypothesis still remains controversial.
M. a. paratuberculosis is difficult to isolate due to long time incubation periods and culture requirements and it has been divided into three groups or clusters: Type I (‘sheep’ or ‘S’ type), Type II (‘cattle’ or ‘C’ type) and Type III (‘intermediate’ or ‘I’). This classification has been achieved by means of different molecular techniques such as IS900-RFLP, PFGE, PCR-REA of gyrB, PCR-REA of inhA, PCR and denaturing gradient gel electrophoresis (DGGE) of MAP1506, PCR-sequencing of recF, PCR-sequencing of IS900, comparative genomic hybridization comparison (CGH), and high resolution melt analysis (HRM). However, in occasions the most slow-growing phenotypes (types I and III) are not typable by some of the above techniques (PFGE and IS900-RFLP) due to DNA requirements. In addition, these two tools are complex and difficult to apply as a routine test to characterize M. a. paratuberculosis.
For this reason, the techniques that are recommended in order to divide M. a. paratuberculosis strains are dependent on the capabilities of each laboratory. Thus, to avoid further steps such as gel electrophoresis or sequencing, HRM would be the first choice due to the obtention of rapid results and its reproducibility. However, for those groups with no HRM technology available, the use of the PCRs specific for each type, derived from the CGH data would be another option. Therefore, by targeting MAV4125 or MAV4126, specific for types I and III and MAP3584 or MAP1435, type III-specific, strains could be easily differentiated. As a result, type I strains would show amplification for both genes, type II for just MAP3584 gene and type III strains just for genes MAV4125 or MAV4126.

	Servicio de Micobacterias (MYC). Centro de Vigilancia Sanitaria Veterinaria (VISAVET). Universidad Complutense (UCM).
	Departamento de Sanidad Animal. Facultad de Veterinaria. Universidad Complutense (UCM).