Pesquisa de Mycobacterium bovis, micobactérias não tuberculosas e actinomicetos em queijo minas artesanal na microrregião do Serro em Minas Gerais

Abstract

The aim of this study was to estimate the occurrence of non-tuberculous Mycobacteria and other Actinomycetes in artisanal cheeses, named of “Queijo Minas Artesanal” (QMA), from Serro, a micro region of Minas Gerais state, Brazil. The presence of pathogens in cheeses with ripening between 4 and 8 days at room temperature means cultivation and molecular speciation methods was evaluated. QMA has been certified or registered by “Instituto Mineiro de Agropecuária (IMA)”, which has endorsed its interstate trade over the country. Of the samples collected (n = 55), 4 (7.27%) showed positive results (4/55) for fast-growing micro-organisms by means of bacterial culture. These isolates from cheeses positive samples were submitted to DNA amplification by PCR, DNA sequencing and its comparison with the sequences deposited in “Basic Local Alignment Search Tool Nucleotide” (BLASTn) database, not restricting the search to genus or species. The sequences identified presented higher similarity with Mycobacterium novocastrense (a sample), nontuberculous mycobacteria (NTM) and Gordonia bronchiallis (three samples) species. All samples of cheeses were from herds subject to intradermal comparative test, as provided by Brazilian programme for the control and eradication of brucellosis and tuberculosis, performed by private accredited veterinarian, showing negative results. Finally, the presence of DNA of Mycobacterium novocastrense and Gordonia bronchiallis in cheeses suggests a supposed disability in the current control of pathogens program, as well as the need for identification measures and stricter control, either at the level of flock as raw materials and the finished product. This gap in the legislation would be something for reflection, given the importance of NTM and other Actinomycetes to public health, especially when aimed at specific groups such as patients with immunosuppression.