berculosis, Mycobacterium africanum, Mycobacterium canetti, Mycobacterium microti, Mycobacterium caprae

online | memorias.ioc.fiocruz.br Bovine tuberculosis (BTB) is an infectious disease primarily caused by Mycobacterium bovis, which affects a wide range of mammals, including humans (Amanfu 2006). M. bovis is a member of the Mycobacterium tuberculosis complex (MTBC), which also includes M. tuberculosis, Mycobacterium africanum, Mycobacterium canetti, Mycobacterium microti, Mycobacterium caprae and Mycobacterium pinnipedii (Cataldi & Romano 2007) and the recently described species Mycobacterium mungi (Alexander et al. 2010) and Mycobacterium orygis (van Ingen et al. 2012). In Argentina, the rate of condemnation of carcasses exhibiting lesions consistent with BTB dropped from 6.7% to 0.7% between 1969-2011 (de Kantor et al. 2012). The last national screening for purified protein derivative (PPD) reactors was performed in 1972 (Nader & Husberg 1988). Therefore, the current prevalence of PPD reactors is unknown, but it may be higher than 0.7% and even higher in dairy cattle. The control strategies are based on the caudal fold skin test, which is used primarily in dairy herds and slaughter surveillance. M. bovis has been isolated from tuberculin-positive bovines after a post mortem inspection of reactors in the slaughterhouse. Although there are no reports of a phenotypic method to distinguish between different M. bovis isolates, genotyping methods have achieved some distinction. Among the molecular methods available for genotyping, the most convenient are spoligotyping (a reverse line probe assay) and genotyping by variable number of tandem repeats (VNTR). At present, the methods for genotyping M. bovis and other MTBC species include restriction fragment length polymorphism (Otal et al. 1991, Collins et al. 1993) and VNTR (Haddad et al. 2001). However, until now, spoligotyping has been the best option for large-scale screening studies on the distribution of M. bovis strains (Kamerbeek et al. 1997). The theories of molecular fingerprinting suggest that epidemiologically related isolates will have similar fingerprints, which are expected to be different from epidemiologically unrelated strains (Maslow et al. 1993). Desirable characteristics for a typing method are related to the stability of the strain and the diversity within the species (Skuce & Neill 2001). Although spoligotyping may fulfil these characteristics in some cases, other typing methods such as VNTR must be performed to discriminate among isolates, especially in settings where one spoligotype is largely predominant or has been used to investigate a recent transmission. doi: 10.1590/0074-0276140292 Financial support: National Agency of Research Promotion of Argentina (PICT 1114) KC and AC are career members of CONICET. + Corresponding author: [email protected] Received 31 May 2013 Accepted 27 November 2013 Genotyping Mycobacterium bovis from cattle in the Central Pampas of Argentina: temporal and regional trends