Comparative study on PCR and microbiological culture performance for identifying Mycobacterium tuberculosis complex and Mycobacterium bovis specie in bovine samples

ABSTRACT

The present study aimed at evaluating the concordance between PCR and microbiological culture techniques for analysing organs samples from cattle with suspected lesions of tuberculosis. Fifty-twosamples collected from slaughter houses were analyzed by microbiological culture, and the extracted DNA was amplified by PCR using NZ1 and NZ2 primers. These primers identify the mycobacteria belongingto M. tuberculosis complex, and the primers pair pncA differentiate the M . bovis from M. tuberculosis species. The colonies isolated from 30 samples were suspended, and the extracted DNA was amplifiedby PCR using the same primer pairs. Although the agreement has been considered weak (k = 0.175) between microbiological culture and PCR performed directly in clinical samples using NZ1 and NZ2 primers, the two pairs of primers could amplify the target genes when 100% of the extracted DNA from 30 isolated colonies were used. Thus, PCR employing pncA primer pair enabled to identify M.bovis in the isolated colonies at a short time when compared with the biochemical assays. The concomitant use of PCR and bacteriologic culture techniques hastens the confirmation of detected agent, which is essential inconducting the epidemiological studies and in taking preventive control measures.