Detection and Species Identification of Leishmania DNA from Filter Paper Lesion Impressions for Patients with American Cutaneous Leishmaniasis

Background. Traditional detection of Leishmania from ulcers involves collection of invasive specimens that cause discomfort, require technical expertise, and carry risks of invasive procedures. We compared traditional diagnostic methods with a molecular noninvasive filter paper–based method for the diagnosis of cutaneous leishmaniasis. Methods. Consecutive patients presenting to the Leishmania Clinic at Hospital Nacional Cayetano Heredia were enrolled. Polymerase chain reaction (PCR) was performed on lesion scrapings, aspirates, and filter paper impressions. The reference standard was any 2 of 5 tests positive: smear, aspirate culture, invasive-specimen PCR (scrapings and aspirates), filter paper PCR, and leishmanin skin test. Outcome measures were sensitivity and specificity. Leishmania speciation was performed by PCR–restriction fragment length polymorphism (RFLP) of positive specimens. Results. Forty-five patients with 66 lesions were enrolled. Of 52 lesions diagnosed as cutaneous leishmaniasis, 50 were positive by PCR of invasive specimens versus 48 by PCR of filter papers (). Sensitivity andPp.930 specificity of PCR on invasively obtained specimens were 94.2 % (95 % confidence interval [CI], 87.9%–100%) and 92.9 % (95 % CI, 79.4%–100%). Sensitivity and specificity of filter paper PCR were 92.3 % (95 % CI, 85.1%–99.5%) and 100%. Culture, smear, and leishmanin skin test all had inferior sensitivities, compared with PCR of invasiv