The diagnostic value of lesional skin smears in cutaneous leishmaniasis made by experienced dermatolog in cutaneous leishmaniasis

Introduction: Leishmaniasis is a common vector-borne infection affecting 12 million people in 98 countries, including Turkey, and over 350 million people are at risk. It is one of the most important vector-borne diseases causing public health problems in the world. Cutaneous leishmaniasis (CL) is the most common form of the disease. The definitive diagnosis of leishmaniasis is based on laboratory methods such as the microscopic examination of Giemsa-stained smears, histopathologic examination, culture or PCR. The most common method for the diagnosis is the microscopic examination of the smear. The sensitivity of this method varies according to the geographical region, the leishmania species, the type of lesion, presence of secondary bacterial infection, the sampling method, smear preparation and the experience of the staff. In this prospective study, it was aimed to emphasize the importance of the experience in the examination of the smears used in the diagnosis of cutaneous leishmaniasis. Methods: Cutaneous leishmaniasis patients diagnosed with various diagnostic methods in the Outpatient Department of Skin and Venereal Diseases of Dicle University Hospital, between January and December in 2016, were included in this study. Two different smears were obtained from each patient by both the microbiologist and the dermatologist experienced in CL and examined independently. Moreover, more samples were taken from the patients for culture [RPMI (Media Designed at Roswell Park Memorial Institute)-1640] and PCR. The results of the smear examinations obtained by the microbiologist and the dermatologist experienced in CL were compared with other diagnostic methods. Results: A total of 122 skin lesions from 70 patients were included in the study. Of 39 (55,7 %) female and 31 (44,3 %) male patients, the mean age was 19 years (age range 3-71). The number of the lesions in each patient varied between 1 and 13, the average lesion number was 1,74. Of the lesions, 4,2 % (5) were papular; 5,7 % (7) were nodular;18 % (22) were noduloulcerative, and 72,1 % (88) were plaques. Whereas culture and PCR were found to be positive for all patients, the smear positivity showed difference between two practitioners. The smear positivity done by the experienced dermatologist in CL was higher than the smear positivity done by the microbiologist (95,7 %, and 42,9 %, respectively) (p<0,001). PCR analyses showed that L. tropica was the leading parasite (n=49; 70%), followed by L. major (n=14; 20%) and L. infantum (n=7; 10%). Comparing the smear positivity rates according to lesion morphologies in the smears performed both by the dermatologist and the microbiologist, a statistically significant difference was not identified (p:0,460, and p:0,091, respectively). Comparing smear positivity rates according to Leishmania species both in the smears performed by the dermatologist and the microbiologist, there was no statistically significant difference (p: 0,274, and p:0,052, respectively). Considering the data obtained from the study, the ITS-1-PCR positivity rate was high as in the studies in the literature. The RPMI-1640 culture positivity rate was the highest positivity rate when compared with the studies in the literature. With respect to those results, it could be stated that ITS-1-PCR and RPMI-1640 culture have high sensitivity and specificity in the diagnosis of cutaneous leishmaniasis. While the positivity rate of the smears by the microbiologist was lower than the rates in the literature, the smear positivity rate by the dermatologist experienced in cutaneous leishmaniasis was the second highest rate in the literature. The findings of our study showed that the smears for the diagnosis of cutaneous leishmaniasis should be performed and evaluated by the dermatologists who are experienced in cutaneous leishmaniasis. Keywords: Cutaneous leishmaniasis, Smear, Dermatologist, Microbiologist, ITS-1-PCR,