RETRACTED: Mycobacterium leprae folP1 gene mutations among dapsone resistant patients in Sudan (Retracted article. See vol. 93, pg. 177, 2022)

Objectives Leprosy is a chronic disease that may cause irreparable deformities. Early diagnosis and proper treatment are crucial. This study examines the reliability of molecular diagnostic methods and their use in monitoring the presence of mutations in the Mycobacterium leprae folP1 gene as an indicator for dapsone resistance among Sudanese leprosy patients. Methods Ninety one skin slit smears were collected from clinically suspected leprosy patients. Modified ZN stain was used as the routine method for diagnosis and as a means to follow-up the response to dapsone therapy among leprosy patients. Two sets of specific primers were used for detecting M. leprae and for amplification of the folP1 gene, followed by sequencing the PCR product. Samples from patients with persistently positive ZN smears were suspected to have dapsone resistance and were therefore examined to study mutations at amino acid codon positions 53' and 55' of the folP1 gene. Results Of 91 smears, only 32 (35.2%) were found positive by ZN stain, while 50 (54.9%) were positive by PCR, showing PCR to be a more sensitive diagnostic method compared to ZN. Of the 32 ZN positive smears, five were found repeatedly positive by ZN after completion of dapsone treatment. Those five samples were subjected to amplification of the folP1 gene and the sequence analysis of the folP1 gene showed various mutations. Three samples showed dual mutations that were previously reported; while two samples demonstrated newly discovered, unreported mutations. The impact of such mutations should be considered in future studies of dapsone therapeutic failure in the region. Conclusions The results indicated that M. leprae strains circulating among Sudanese patients harbor mutations previously reported at position 55 (Ser) and position 53 (Glu). Further research is required to elucidate the effect of other mutations.