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Genotyping and screening of phenotypic and genetic resistance to rifampicin and isoniazid in Mycobacterium bovis strains isolated from bovine lymph nodes from slaughterhouse in Midwestern region of São Paulo State

Grant number: 14/04929-7
Support type:Scholarships in Brazil - Doctorate
Effective date (Start): July 01, 2014
Effective date (End): August 31, 2016
Field of knowledge:Agronomical Sciences - Veterinary Medicine - Preventive Veterinary Medicine
Cooperation agreement: Coordination of Improvement of Higher Education Personnel (CAPES)
Principal researcher:Antonio Carlos Paes
Grantee:Marília Masello Junqueira Franco
Home Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

Tuberculosis is a chronic infectious disease, caused by M. tuberculosis complex bacteria. The disease has a worldwide distribution, affecting humans, domestic and wild animals. Although tuberculosis caused by M. bovis (bTB) has a broad host range, it primarily affects cattle and can be transmitted to humans by the consumption of milk or dairy products without heat treatment, as well as the inhalation of infectious aerosols, mainly in immunosuppressed individuals. Currently, in developed countries bTB corresponds to 1-2% of tuberculosis cases in humans. In contrast, in developing countries, it is estimated that 10-15% of human TB cases are caused by M. bovis. In Brazil, the situation of the bTB is not well known because there are no recent epidemiological studies that objectively provide the frequency of M. bovis infection in the human population. In the national territory, bovine tuberculosis is still a major problem in animal health, data from official reports indicate average prevalence of 1.3% in the period 1989-1998. So far the Ministry of Agriculture, Livestock and Supply has not released the latest official epidemiological data on the disease. The worldwide emergence of multidrug resistant (MDR-TB) and extreme drug resistant (XDR-TB) strains of mycobacteria, and the re-emergence of bTB sets an alert condition to the international scientific and medical community. International studies have reported strains of M. bovis resistant to isoniazid (INH) and rifampicin (RMP) isolated from infected cattle. There were not found national studies that show the presence of INH and RMP resistance in strains of M. bovis isolated from Brazilian herds. The present study aims to characterize the genotypic diversity of M. bovis strains in the enrolled area, as well as to investigate the phenotypic profile of resistance of these strains to two of the first-line drugs in tuberculosis treatment and to detect possible genetic basis of such resistance. Will be collected 100 lymph nodes that shows lymphadenitis, from different carcasses, inspected during slaughter line in a slaughterhouse supervised by the Federal Inspection Service. After decontamination by the Petroff method, samples will be cultivated in Stonebrink and Lowenstein-Jensen media. The bacteria characterized as acid-fast bacilli Will be classified by molecular techniques. Genotyping techniques (spoligotyping and MIRU-VNTR) will be performed in the isolates classified as M. bovis, as well as the phenotypic resistance assay to INH and RMP by REMA method. The strains of M. bovis that show phenotypic resistance to the antimicrobials tested (one or both), will be submitted to DNA sequencing of inhA, katG, ahpC and rpoB genes for the identification of resistance-associated mutations. A thorough understanding of the molecular epidemiology of M. bovis infections in cattle may contribute to the control and eradication of bovine tuberculosis. The investigation of drug resistance in these bacteria provides subsidies for the implementation of more effective therapeutic measures in zoonotic tuberculosis, to optimize the use of public financial resources in health systems and consequently to decrease the risk of transmission between humans. (AU)

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Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
JUNQUEIRA FRANCO, MARLIA MASELLO; RIBEIRO, MARCIO GARCIA; PAVAN, FERNANDO ROGERIO; MIYATA, MARCELO; HEINEMANN, MARCOS BRYAN; DE SOUZA FILHO, ANTONIO FRANCISCO; CARDOSO, ROSILENE FRESSATTI; DE ALMEIDA, ARYADNE LARISSA; SAKATE, RICARDO ICHIRO; PAES, ANTONIO CARLOS. Genotyping and rifampicin and isoniazid resistance in Mycobacterium bovis strains isolated from the lymph nodes of slaughtered cattle. TUBERCULOSIS, v. 104, p. 30-37, MAY 2017. Web of Science Citations: 6.
Academic Publications
(References retrieved automatically from State of São Paulo Research Institutions)

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