Estudio de Mycobacterium bovis en leche mediante métodos bacteriológicos y reacción en cadena de la polimerasa / [Study of Mycobacterium bovis in milk using bacteriological methods and the polymerase chain reaction]

The frequency of Mycobacterium bovis detection in milk samples obtained from infected animals was explored in an intensive dairy area in Argentina. To this end, an [quot ]in house[quot ] polymerase chain reaction (PCR) method was developed using Mycobacterium tuberculosis Complex specific INS1-INS2 primers, and its performance was compared with that of bacteriological methods. The decontamination procedures previous to culture reduced M. bovis viability. The pathogen was identified in milk samples from 1 of 143 infected cows and in none of 43 uninfected ones. Even though PCR sensitivity was found to be 2-20 times higher than that of bacteriology in experimentally inoculated milk samples, all 186 field samples resulted negative by PCR, including the bacteriologically-confirmed one. In spite of the high prevalence of bovine tuberculosis in Argentinian dairy herds, the detection of M. bovis in milk is an unusual finding.