A Novel RNA In Situ Hybridization Method for the Detection of Mycobacteria in Clinical FFPE Samples - Presented at: USCAP 2019

Acid fast staining (AFS) for the detection of mycobacteria and other acid-fast organisms provides a rapid way of identifying pathogenic organisms in FFPE tissue in contrast to culture methods, which require weeks to perform. While rapid and straightforward, there are several issues with AFS. First, AFS can be challenging and time-consuming to interpret. Second, standard tissue fixatives and processing alters the lipid-rich cell wall of acid-fast organisms which reduces the detection sensitivity in FFPE samples. Last, AFS does not allow for discrimination between various acid-fast organisms, such as mycobacteria tuberculosis (MTB) vs. non-tuberculous mycobacteria (NTM). To address these issues with AFS, we have developed a highly sensitive and specific RNA in situ hybridization (RISH) assay using the RNAscope technology for the detection of mycobacteria rRNA in FFPE tissues and distinction of MTB and NTM.