Molecular Detection of Mycobacterium tuberculosis in Tissues Showing Granulomatous Inflammation Without Demonstrable Acid-Fast Bacilli

Abstract

Early diagnosis of tuberculosis (TB) is important for early medical intervention and prevention of spread of the bacteria. It is not uncommon to observe granulomatous inflammation but without demonstrable acid-fast bacilli (AFB) on Ziehl-Neelsen (ZN) staining in tissues sent for histologic examination, and the definitive diagnosis of TB cannot be made because no concurrent tissue is sent for TB culture. In this study, the authors explored the feasibility of using polymerase chain reaction (PCR) for early detection of Mycobacterium tuberculosis (Mtb) in formalin-fixed, paraffin-embedded tissues where a definite diagnosis of TB cannot be made. One hundred fifteen patients (131 paraffin blocks of biopsy specimens) with granulomatous inflammation but ZN-negative for AFB were studied. DNA was extracted from paraffin sections and amplified by PCR with the IS6110 primers (specific for the Mtb complex) and the specific 122-base pairs (bp) PCR product was detected by agarose gel electrophoresis. Sixty-eight of the 115 (59%) patients were TB-PCR positive, thus enabling definite diagnosis of TB in significant numbers of these patients in 3 days. The authors conclude that molecular diagnosis by PCR is useful for early detection of TB in histologic material where morphologic features are suggestive but not confirmatory because of negative staining for AFB.

Nested PCR in lung tissue for diagnosis of pulmonary tuberculosis

“…Many prior studies have reported on the performance of PCR on various types of formalin-fixed, paraffin-embedded human tissues [11,[19][20][21]. In these reports, the sensitivity of the PCR ranged 66-100% and varied according to the method of PCR, target sequence and characteristics of the tissue specimens.…”

Detection of Mycobacterium tuberculosis Complex in Formalin-Fixed, Paraffin-Embedded Tissue Specimens with Necrotizing Granulomatous Inflammation by Strand Displacement Amplification

“…Previous studies have described the use of PCR on human FFPE specimens for detection of MTC DNA with promising results, but almost all of them used in-house PCR methods. [15][16][17][18][19] The BDProbeTec ET Direct Detection assay (Becton Dickinson, Sparks, MD, USA) is commercially available for the detection of MTC in clinical specimens. This assay is based on simultaneous strand displacement amplification of MTC-specific IS6110 target DNA of 95 bp and real-time detection by fluorescentlabeled probes.…”

Eficacia del diagnóstico diferencial de tuberculosis mediante reacción de polimerasa en cadena en lesiones granulomatosas de tejidos fijados en formalina e incluidos en parafina

“…Se han publicado diversos estudios en los que se reporta el uso de RPC en muestras de TFFP 26,[34][35][36][37] ; sin embargo, este es el primer estudio en el que se analiza una gran cantidad de muestras y en el que se incorpora una clasificacion del tipo de granuloma.…”