A Comparative Study Of Ziehl-Neelsen & Modified Fite-Faraco With Auramine Rhodamine Staining In Detection Of Mycobacterium Leprae In Tissue Sections

Abstract

BACKGROUND: Leprosy is a chronic infectious disease caused by mycobacterium leprae. In leprosy, histopathological examination of skin offers the correct diagnosis. We evaluate fluorescent microscopy which is increasingly used for rapid screening. OBJECTIVES: 1. To compare the efficacy of auramine rhodamine stain (FS) with ZiehlNeelsen(ZN) and modified Fite-faraco(FF) staining in the diagnosis of leprosy in tissue sections. 2. To assess the role of auramine rhodamine staining method in grading of Hansen’s disease. METHODOLOGY:Skin biopsies of sixty clinically diagnosed leprosy patients received in the department of pathology were subjected to ZN stain, FF stain and FS. Each case was evaluated for presence of bacilli as well as bacillary index (BI). RESULTS: Sensitivity of FS for indeterminate, borderline tuberculoid leprosies were 100% each. Positivity rates and mean BI with FS was higher as compared to that of ZN and Fite-faraco when the bacillary load was less (BI <3). There was significant correlation between the three staining types at lower bacillary load. There was a higher mean BI with fluorescent stain as well as detection of an additional multibacillary case. CONCLUSION: Fluorescent method is more sensitive than modified fite-faraco method in detecting lepra bacilli in tissue sections especially in cases with BI<3. It has an additional role in grading of Hansen’s disease based on BI. Hence it can prove valuable in tissue sections with lower bacillary load where other methods fail.