Molecular Detection of Mycobacterium leprae in Stained Slit Skin Smear from leprosy Patients and Comparison of Molecular and Histopathological Findings with Clinical Data
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Date
2017-06
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Addis Ababa University
Abstract
Background:Mycobacterium leprae is a causative agent of leprosy which is a chronic infectious disease. The disease mainly involves the skin and peripheral nerves. Leprosy is endemic in tropical countries especially in developing countries.Globally theprevalence of leprosy at the end of 2015 was 210,758 cases (3.2 cases per 100, 000 populations)and the number of new cases reported globally in the same year was 199,992. The Aim of this study was to improve the sensitivity of leprosy laboratory diagnosisusing PCR on Archival ZN Stained Slide of Skin Smear and to compare with other tests.
Objective: To evaluate the diagnostic performance of PCR to detect M. leprae on stained Slit Skin Smear collected from clinically confirmed leprosy patients.
Methodology:Retrospective cross sectional study was conducted on 60 clinically confirmed leprosy patients of 42MB and 18PB leprosy cases and Archival sample ZN stained slides on SSS and archival data of H&E and FF on biopsy stained slides of the sixty leprosy patients were collected from the AHRI histopathology laboratory.
Results: The PCR on SSS was positive in 6 (10.00%) PB patients and in 23 (38.67%) MB patients. Among the 23 MB cases detected by PCR 3, and among PB cases detected 2 were from AFB negative slides. Histopathological findings were graded according to Ridley and Jopling scale where most common histological type was BT seen in 14(23.33%) cases followed by BL
8(13.33%) cases, LL 8(13.33%), BB 7 (11.67%), TT 5 (8.33%), and IL 3 (5%). Majority (71.67%) of the cases was MB type and the rest (28.33%) were PB. Faite-Faraco staining was positive in 37 (61.7%) cases.
Conclusion: The PCR on SSS detected a total of 29 out of 60 samples indicating its potential for diagnosis. Although PCR on SSS showed low detection as compared to H&E and FF staining (staining on punch biopsy samples), it detected more positive samples than ZN staining. Therefore, by improving some technical procedures in sample collection and handling, it can be used for diagnosticswhere PCR machines are available. XIII
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Histotechnology;Pathology