Genetic diversity of Mycobacterium avium sp paratuberculosis isolates from Buenos Aires, Argentina by MIRU-VNTR analysis

B R IMPERIALE; R D MOYANO; M A ROMERO; ALVARADO PINEDO MF; M P SANTANGELO; G TRAVERIA; ROMANO MI

Congreso; 13th International Colloquium on Paratuberculosis; 2016

Paratuberculosis (PTB) is an infectious gastroenteritis caused by M. avium subsp. paratuberculosis (Map) that affects mainly ruminants, and it has been postulated a potential zoonotic role in human Cohn?s disease. It has a significant impact on the economy. Control of PTB requires a better knowledge of the causative agent and of its epidemiology. Objective. The aim of this study was to determine the diversity of Map strains spreading in Argentina. Materials and Methods. This study included isolated strains obtained from faeces of cattle. Samples were decontaminated using hexadecyl pyridinium chloride and cultured in Herrold´s media supplemented with mycobactin. Mycobacteria were identified by Ziehl-Neelsen stain. IS1311 PCR was performed to identify M. avium complex (MAC) while the IS900 PCR was used to identify Map. Map isolates were classified as type C/S according to IS1311 PCR-REA. Genotyping was performed through the analysis of eight MIRU-VNTR loci (292, X3, 25, 47, 3, 7, 10, 32) previously described by Thibault et al 2007. The analysis was performed using unlabeled and fluorescent labeled primers. The patterns were assigned according with INMV database (http://mac-inmv.tours.inra.fr/) (INRA, Nouzilly). The allelic diversity and the Hunter and Gaston discriminatory index (HGDI) were determined through http://insilico.ehu.es/mini_tools/discriminatory_power/index.php. Results. A total of 61 Map isolates belonged to C type were analyzed. A total of 59 out of 61 (96.7%) isolates could be genotyped and 5 different INMV patterns were found: INMV 1 (42.4%), INMV 2 (28.8%), INMV 11 (20.3%), INMV 8 (5.1%) and INMV 5 (3.4%). The highest discriminatory power (D) was obtained for MIRU 292 and VNTR 7 (0.5 and 0.3 respectively) and the global HGDI for the MIRU-VNTR analysis was 0.7043.Discussion. Most of the isolates included in the study could be genotyped and the frequency of the INMV pattern found in Argentina are in concordance with those previously reported by other authors. INMV 1 and 2 are the main genotypes spreading worldwide. The HGDI was similar to others previous reports (HGDI 0.751, Thibault et al).