Leprosy in a low-incidence setting : Case report relevant to metagenomic next generation sequencing applications

Leprosy is a disease caused by Mycobacterium leprae that results in disability. In 2000 the World Health Organization announced that leprosy had been eradicated. In nonendemic areas diagnosing leprosy is becoming a challenge for inexperienced clinicians. This case involves a male patient suffering from chronic numbness, hand deformity and recurrent erythema. Skin biopsy revealed granuloma and acid-fast staining of short-rod bacteria. Peripheral venous blood was subjected to metagenomic next generation sequencing and bioinformatics analysis, which revealed 3 unique sequence reads of M. leprae. Paraffin-embedded tissue and fresh samples scraped from skin lesions were subjected to in-house PCR targeting 16S rRNA, hsp65, rpoB, rpoT, ribF-rpsO, and mmaA. Sanger sequencing of amplicons from fresh samples and paraffin-embedded tissue verified the presence of M. leprae. For inexperienced clinicians in nonendemic areas nucleic acid amplification tests, such as in-house PCR, are helpful for diagnosing leprosy but sequence reads from metagenomic next generation sequencing may also provide evidence when interpreted cautiously.