Uso da Nested PCR em tempo real para o diagnóstico de tuberculose em carcaças bovinas

Abstract

Bovine tuberculosis (TB) is a zoonotic disease caused by Mycobacterium bovis. Its diagnosis is key to their control and eradication, being carried through the tuberculin test, with slaughter of animals in slaughterhouses reagents and surveillance, but this strategy can provide erroneous results. In the post mortem diagnosis, are traditionally used macroscopic examination and bacteriological culture often imprecise and slow respectively. An alternative that permits rapid diagnosis with increased sensitivity and specific identification of M. bovis in fragments of suspicious lesions of TB are molecular tests. Therefore, this study aimed to implement and evaluate the use of nested real-time PCR (nested q-PCR) in post mortem inspection of carcasses with suspicious lesions of bovine tuberculosis. To do so, followed the killing and post mortem examination of 41,193 cattle slaughtered in slaughterhouses holders of Federal Inspection Service (SIF), suspicious lesions were collected and sent for microbiological tests (culture) and molecular (multiplex PCR – m-PCR and nested q - PCR). Among the total number of carcasses examined, 198 (0.48%) showed lesions suspicious of TB according to the macroscopic examination. The nested q-PCR confirmed infection with M. bovis in 28% (56/198) of the lesions suspected tuberculosis, while in culture and m-PCR, it was possible to obtain 1.5% (3/198) and 7.0% (14/198) of infected injuries respectively. The nested q-PCR applied directly on the lesions suspicious of TB technique proved to be a sensitive, specific and rapid, which allows to detect the presence of M. bovis in just 10 hours, and can be used as a complementary method of inspection and contribute to the program of control and eradication of bovine tuberculosis in disease surveillance in slaughterhouses, in tracking and sanitation remaining foci.