Abstract
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.
Highlights
Leprosy is a chronic infectious disease that most commonly affects the skin, peripheral nerves, eyes and nose
The results indicated that M. leprae strains circulating among Sudanese patients harbor mutations previously reported at position 55 (Ser) and position 53 (Glu)
The 91 slit skin smears were examined by the conventional ZN stain; thirty two (35.2%) were positive, while 50 (54.9%) were positive by PCR (Table 2)
Summary
Leprosy is a chronic infectious disease that most commonly affects the skin, peripheral nerves, eyes and nose. It causes disfigurement of the eyes, nose, feet and hands.[1] The disease can present a wide spectrum of symptoms and signs depending on the balance between the infectious organisms and the immune status of the patient.[2] Changes in the patient’s immune status over time have a direct effect on the number of bacteria detected and this in turn can affect the detection of the organism by routine histopathologic and staining methods leading to false negative results. Dapsone is commonly used in combination with rifampin and clofazimine to treat leprosy as an antibacterial drug The introduction and use of the polymerase chain reaction for the detection of M. leprae in suspected cases is expected to increase the sensitivity of laboratory diagnosis; leading to an accurate and definitive diagnosis.[3]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
