Submitted to: International Virtual Conference on Infectious Diseases of Animals
Publication Type: Abstract Only
Publication Acceptance Date: 4/20/1997
Publication Date: N/A
Technical Abstract: A presumptive diagnosis of tuberculosis is based on the finding of characteristic histopathologic lesions and acid-fast organisms. Definitive diagnosis, however, requires culture and identification of the causative mycobacterium, a process that takes several weeks. The purpose of work reported here was to determine if formalin-fixed paraffin-embedded tissues could be tested by polymerase chain reaction (PCR) to provide a more rapid diagnosis. Paraffin sections of nondecalcified tissue from 99 culture-positive cases of tuberculosis were examined. Primers used for the PCR amplified a 123 bp fragment of IS6110, an insertion sequence that identifies organisms in the M. tuberculosis complex (M. tuberculosis, M. bovis, M. microti, and M. africanum). The IS6110 sequence was detected in 92 (93%) of the paraffin sections tested. In 80 cases the positive results were obtained using material prepared by a simplifed extraction method that eliminated several traditional steps (paraffin removal, enzyme digestion, and DNA purification). Specificity of the IS6110 PCR test was demonstrated by examining paraffin sections from 31 nontuberculous lesions (granulomas caused by other mycobacteria and nonmycobacterial granulomas), all of which gave negative results.