Iranian Journal of Pathology

Fluorescent Microscopy: A Useful and Adjunct Tool in Leprosy Diagnosis: A Cross Sectional Study

Document Type : Original Research

Authors

Swati A Jain 1
vaishali A Walke 2
Dinesh Asati 3
Anand Mourya 4
Sramana Mukhopadhyaya 2

1 Peoples College of Medical Sciences and Research Centre, Bhopal (MP), India

2 Path & Lab Medicine, All India Institute of Medical Science, Bhopal. India

3 Department of Dermatology, LN Medical College, Bhopal. India

4 Microbiology Department, All India Institute of Medical Science, Bhopal. India

https://doi.org/10.30699/ijp.2024.2023590.3263
Abstract
Background & Objective: Leprosy is a chronic infectious disease caused by Mycobacterium leprae. Fite-Faraco (FF) is the routine staining method used to demonstrate the presence of Mycobacterium leprae in tissue sections. Fluorescent microscopy (FM) can help visualize lepra bacilli better. The present study compares two methodologies, fluorescent microscopy, and Fite-Faraco, in detecting Mycobacterium leprae in tissue sections.
Methods: Histopathology of skin biopsies in 60 cases of Hansen's were evaluated with FF stain. The performance of Auramine- Rhodamine Fluroscencent stain was compared with conventional FF staining in identifying Lepra bacilli.
Results: A total of 60 clinically and histopathologically confirmed cases of Hansen’s disease were included in this ambispective study. The cases were sub-classified into various histological categories. Auramine-rhodamine fluorescent staining was performed and examined under a fluorescent microscope with an LED light illuminator. The bacteriological index (BI) was calculated under an oil immersion field for both Fite-Faraco (FF) staining and fluorescent microscopy (FM), graded from zero to six plus according to Ridley’s logarithmic scale. Lepra bacilli were identified in 70% of patients on FF staining, while fluorescent microscopy showed positivity in 80%. The mean BI calculated by FM (2.48) was significantly higher than that by the FF method (2.18), and more multibacillary disease was identified by fluorescent staining compared to FF staining.
Conclusion: It is advantageous to use fluorescent microscopy as an adjunct to conventional Fite-Faraco stain especially in cases where the latter fails to detect lepra bacilli and in a clinically suspected multibacillary disease.

Highlights

  • It is advantageous to use fluorescent microscopy as an adjunct to conventional Fite-Faraco stain, especially in cases where the latter fails to detect lepra bacilli and in clinically suspected patients of multibacillary disease.
  • Screening of Auramine- Rhodamine-stained section requires significantly less time and is effortless for the observer.
  • The presence of bacilli and assessment of bacillary load in tissue sections significantly impact treatment options.
  • Fluorescent microscopy's higher bacilli pick-up rate will avoid undertreatment of leprosy owing to its lower false negativity, thereby decreasing treatment failures and relapses.

Keywords

Auramine-rhodamine
Fite-Faraco
Fluorescent stain
Hansen’s Diseas

Subjects

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Iranian Journal of Pathology
Volume 20, Issue 1
Winter 2025
Pages 33-41

  • Receive Date 24 February 2024
  • Revise Date 24 March 2024
  • Accept Date 06 December 2024

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