Fluorescent Hybridization of Mycobacterium leprae in Skin Samples Collected in Burkina Faso

Abstract

Leprosy is caused by Mycobacterium leprae, and it remains underdiagnosed in Burkina Faso. We investigated the use of fluorescent in situ hybridization (FISH) for detecting M. leprae in 27 skin samples (skin biopsy samples, slit skin samples, and skin lesion swabs) collected from 21 patients from Burkina Faso and three from Côte d'Ivoire who were suspected of having cutaneous leprosy. In all seven Ziehl-Neelsen-positive skin samples (four skin biopsy samples and three skin swabs collected from the same patient), FISH specifically identified M. leprae, including one FISH-positive skin biopsy sample that remained negative after testing with PCR targeting the rpoB gene and with the GenoType LepraeDR assay. Twenty other skin samples and three negative controls all remained negative for Ziehl-Neelsen staining, FISH, and rpoB PCR. These data indicate the usefulness of a microscopic examination of skin samples after FISH for first-line diagnosis of cutaneous leprosy. Accordingly, FISH represents a potentially useful point-of-care test for the diagnosis of cutaneous leprosy.

Keywords: Mycobacterium; Mycobacterium leprae; fluorescent hybridization; leprosy; skin.

FIG 1

Fluorescent in situ hybridization (FISH) of Mycobacterium leprae in skin biopsy specimens collected from patients suspected of having cutaneous leprosy in Burkina Faso. Rows 1, 2, and 3 show positive skin biopsy specimens from patients P2, P4, and P5, respectively (Table 1); row 4 shows a negative-control skin biopsy specimen from patient 8111270308 (Table 1). (A) Ziehl-Neelsen staining; (B) FISH-DAPI staining; (C) results of the GenoType LepraeDR test and PCR amplification of the rpoB gene. +, positive; −, negative. Bar, 10 μm.