Ruwandi Kariyawasam1, Braulio M Valencia2,3, Rachel Lau4, Eric Shao5, Courtney A Thompson6,7,8, Michael Stevens9, Leah Kincaid10, Ana Luz Quispe Del Castillo2, Lloysi O Cruz-Arzapalo11, Alejandro Llanos-Cuentas2,12, Andrea K Boggild13,14,15. 1. Institute of Medical Science, University of Toronto, Toronto, ON, Canada. 2. Instituto de Medicina Tropical "Alexander Von Humboldt", Lima, Peru. 3. Kirby Institute, University of New South Wales, Sydney, Australia. 4. Public Health Ontario Laboratory, Toronto, ON, Canada. 5. Department of Microbiology and Immunology, Western University, London, ON, Canada. 6. Department of Medicine, University of Toronto, Toronto, ON, Canada. 7. Tropical Disease Unit, Toronto General Hospital, 200 Elizabeth Street, 13EN-218, Toronto, ON, M5G 2C4, Canada. 8. Markham-Stouffville Hospital, Markham, ON, Canada. 9. Division of Clinical Dermatology and Cutaneous Science, Department of Medicine, Dalhousie University, Halifax, NS, Canada. 10. Alliance Dermatology Associates, Lawrenceville, NJ, USA. 11. Hospital de Apoyo Pichanaki, Direccion Regional de Salud, Junin, Peru. 12. Facultad de Ciencias, Universidad Peruana Cayetano Heredia, Lima, Peru. 13. Institute of Medical Science, University of Toronto, Toronto, ON, Canada. andrea.boggild@utoronto.ca. 14. Department of Medicine, University of Toronto, Toronto, ON, Canada. andrea.boggild@utoronto.ca. 15. Tropical Disease Unit, Toronto General Hospital, 200 Elizabeth Street, 13EN-218, Toronto, ON, M5G 2C4, Canada. andrea.boggild@utoronto.ca.
Abstract
PURPOSE: Overlapping clinical features of cutaneous leishmaniasis (CL) with ulcers caused by fungi and mycobacteria necessitate confirmatory diagnostic testing. We evaluated a handheld battery-operated device for detection of CL and common fungal and mycobacterial causes of ulcers. METHODS: We validated Palm PCR™ for detection of common ulcerative skin pathogens using ATCC® reference and clinical strains of Leishmania, mycobacteria, and fungi in the lab and field. Amplified products were Sanger sequenced. Performance characteristics were calculated using conventional PCR as a reference standard. RESULTS: Palm PCR™ detected 100% of ATCC® strains of Leishmania, fungi, and mycobacteria, with sensitivity and specificity of 90% and 91.7%, respectively. In the field, the sensitivity for detection of Leishmania in patients with suspected CL was 100%. In 61% of CL patients, co-colonization with genera such as Malassezia, Aspergillus, Candida, and Cladosporium was detected. In 50% of CL patients with an inflammatory (secondarily infected) phenotype, detected fungal species had known associations with human cutaneous disease. CONCLUSIONS: Palm PCR™ performs comparably to conventional PCR for detection of Leishmania, fungi, and mycobacteria. This work has implications for the diagnostic approach to tropical ulcers, and has the potential to improve field detection of ulcerative pathogens in resource constrained areas.
PURPOSE: Overlapping clinical features of cutaneous leishmaniasis (CL) with ulcers caused by fungi and mycobacteria necessitate confirmatory diagnostic testing. We evaluated a handheld battery-operated device for detection of CL and common fungal and mycobacterial causes of ulcers. METHODS: We validated Palm PCR™ for detection of common ulcerative skin pathogens using ATCC® reference and clinical strains of Leishmania, mycobacteria, and fungi in the lab and field. Amplified products were Sanger sequenced. Performance characteristics were calculated using conventional PCR as a reference standard. RESULTS: Palm PCR™ detected 100% of ATCC® strains of Leishmania, fungi, and mycobacteria, with sensitivity and specificity of 90% and 91.7%, respectively. In the field, the sensitivity for detection of Leishmania in patients with suspected CL was 100%. In 61% of CL patients, co-colonization with genera such as Malassezia, Aspergillus, Candida, and Cladosporium was detected. In 50% of CL patients with an inflammatory (secondarily infected) phenotype, detected fungal species had known associations with humancutaneous disease. CONCLUSIONS: Palm PCR™ performs comparably to conventional PCR for detection of Leishmania, fungi, and mycobacteria. This work has implications for the diagnostic approach to tropical ulcers, and has the potential to improve field detection of ulcerative pathogens in resource constrained areas.
Authors: Eva Dueñas; Jose A Nakamoto; Luis Cabrera-Sosa; Percy Huaihua; María Cruz; Jorge Arévalo; Pohl Milón; Vanessa Adaui Journal: Front Microbiol Date: 2022-09-15 Impact factor: 6.064