ABSTRACT
A test based on amplification of 169 bp DNA specific to Mycobacterium tuberculosis was evaluated in a trial, on 50 coded samples which included 25 sputum specimens from radiologically, clinically and bacteriologically proven patients of pulmonary tuberculosis and 25 control specimens. At the end of the trial the code was broken and the results of PCR test were compared with those obtained with Ziehl Neelsen staining and culture test. The test appeared highly sensitive reacting 100 per cent in either of the hands with concordance rate of 76 per cent; 3 of 25 control samples gave false positive results.
Subject(s)
Evaluation Studies as Topic , Humans , Mycobacterium tuberculosis/isolation & purification , Polymerase Chain Reaction , Specimen Handling/methods , Sputum/microbiologyABSTRACT
A recombinant genomic clone was isolated from a lambda gt 11 library of M. tuberculosis on the basis of lack of hybridization with M. avium and M. kansasi. The specificity and sensitivity of M. tb DNA probes, 2.5 and 2.3 kb in size, were assessed by Southern blot and dot blot hybridization. These did not cross hybridize to DNA of mycobacteria other than members of M. tb complex, nor with DNA of non mycobacterial origin. Sensitivity was determined to be 200 pg which is equivalent to 10(4) bacilli. Genomic Southern hybridization indicated single copy nature of the probes.