Detection of mycobacteria in paraffin-embedded Ziehl-Neelsen-Stained tissues using digital pathology.

Abstract Introduction Early diagnosis of paucibacillary tuberculosis represents a challenge, even with direct tissue examination. Digital pathology allows the digital analysis of tissues to identify microorganisms. We aim to develop a program to detect and quantify typical and atypical mycobacteria in paraffin-embedded Ziehl–Neelsen-stained tissues. Material and methods Program development: The building of the program, named Pat-Scan, included pathology, systems engineering, and scientific applications. The iScan Coreo Au scanner® was used, and 9 variables were adjusted. Ten Ziehl–Neelsen-stained samples were fragmented into 2,000 images and analyzed to validate the reproducibility of the bacilli images in the tissue, as detected by the software. Results Pat-Scan included software and a scanner that were used to detect and quantify bacilli in paraffin-embedded Ziehl–Neelsen-stained tissues. All samples containing mycobacteria were successfully analyzed by the scanner, and the bacilli could be detected; these results were validated by expert pathologists by microscopy examination, and the presence of bacilli was confirmed in all cases. Conclusions Pat-Scan allowed the identification and quantification of mycobacteria in paraffin-embedded Ziehl–Neelsen-stained tissues, offering a reproducible diagnostic method that reduces the time for diagnosis and does not affect precision. Further validation is needed for application in the clinical setting.