MILK CONTAMINATION BY Mycobacterium tuberculosis complex, IMPLICATIONS FOR PUBLIC HEALTH IN AMAZONAS, BRAZIL

Abstract

In Brazil, contamination of raw milk with Mycobacterium tuberculosis complex (MTC) has been reported in several states. In Amazonas, the rate of consumption of raw milk and its derivatives is the highest in the country. The state has the highest prevalence of tuberculosis in both humans and livestock. Therefore, we assessed the contamination of cattle and buffalo milk with MTC in the state of Amazonas, focusing on Mycobacterium bovis (M. bovis) , the species most commonly originating in cattle and buffalo. In 2019, 250 samples of raw milk (91 cattle; 159 buffalo) were collected from three milk plants, before the processing, in the state of Amazonas. The samples were placed into 21 pools then analyzed using Shotgun Metagenomic Sequencing and taxonomic classification by Kraken-2 and MegaBLAST. To confirm the identity of Mycobacterial species found, BLASTN was used to identify specific genomic positions at the TbD1 and RD1 regions and flanking RD4 region. MTC species genetic material were identified in all pools of raw milk. Genetic material consistent with M. bovis were identified in seven pools of raw milk (1 cattle and 6 buffalo). Milk from buffalo presented significantly higher MTC reads than milk from cattle. The common practice of consumption of raw milk and its derivatives in Amazonas presents an imminent risk to public health. Urgent measures to prevent transmission of foodborne tuberculosis are needed in the Amazon region. Greater efforts and resources should also be directed towards elimination of bovine tuberculosis disease in cattle and buffalo herds in the state of Amazonas and all of Brazil.