Identification of two novel Mycobacterium avium allelic variants in pig and human isolates from Brazil by PCR-restriction enzyme analysis

Mycobacterium avium complex (MAC) is composed of environmental mycobacteria found widely in soil, water, and aerosols that can cause disease in animals and humans, especially disseminated infections in AIDS patients. MAC consists of two closely related species, M. avium and M. intracellulare, and may also include other, less defined groups. The precise differentiation of MAC species is a fundamental step in epidemiological studies and for the evaluation of possible reservoirs for MAC infection in humans and animals, In this study, which included 111 pig and 26 clinical MAC isolates, two novel allelic M. avium PCR-restriction enzyme analysis (PRA) variants were identified, differing from the M. avium PRA prototype in the HaeIII digestion pattern. Mutations in HaeIII sites were confirmed by DNA sequencing, Identification of these isolates as M, avium was confirmed by PCR with DT1-DT6 and IS1245 primers, nucleic acid hybridization,vith the Accu-Probe system, 16S ribosomal DNA sequencing, and biochemical tests. The characterization of M. avium PRA variants can be useful in the elucidation of factors involved in mycobacterial virulence and routes of infection and also has diagnostic significance, since they can be misidentified as M. simiae II and M. kansasii I if the PRA method is used in the clinical laboratory for identification of mycobacteria.Univ Fed Sao Paulo, Escola Paulista Med, Disciplina Microbiol, Dept Microbiol Immunol & Parasitol, BR-04023062 Sao Paulo, BrazilUniv Sao Paulo, Dept Med Vet Prevent & Saude Anim, Fac Med Vet & Zootecn, Sao Paulo, BrazilCtr Nacl Pesquisa Suinos & Aves, Empresa Brasileira Pesquisa Agropecuaria, Concordia Santa Catarina, BrazilUniv Fed Sao Paulo, Escola Paulista Med, Disciplina Microbiol, Dept Microbiol Immunol & Parasitol, BR-04023062 Sao Paulo, BrazilWeb of Scienc