[Investigation of Polymerase Chain Reaction Method in Patients with Suspected Chronic Cutaneous Leishmania of Negative Microscopy]

Abstract

Leishmaniasis is a parasitic disease that is transmitted to humans by the bites of infected female phlebotomine sandflies. In the diagnosis of cutaneous leishmaniasis (CL), in the smear samples, the demonstration of the parasite by microscope remains a gold standard method. However, it becomes difficult to diagnose the parasite since the number of amastigotes in chronic cases with a lesion of one year or longer is very low. Due to many factor such as patients primarily do not to take any notice these lesions in their bodies, do not apply to health institutions or late applied, receive wrong treatment; the diagnosis and treatment are delayed. In addition, it is been worse prognosis by add secondary infection to lesions and wounds become chronic. For this reason, molecular methods are used in addition to microscopic examination in chronic suspected CL cases. It was aimed to reveal of the molecular diagnostic value in chronic suspected CL cases by polymerase chain reaction (PCR) in the smear belonging to Turkish patients that reported to be evaluated clinically because it can not be seen Leishmania amastigotes in microscopic examination. Smear of 50 Turkish patients who were clinically reported of the evaluation of chronic CL were selected. These samples were smears belonging to suspected CL patients that applied Hatay Mustafa Kemal University, Faculty of Medicine, Parasitology laboratory from different polyclinics and were decided to be evaluated clinically as a result of microscopic examination because they came from endemic regions (such as Hassa, Altınözü, Yayladağı). DNA was isolated from selected samples and PCR was performed using 13A, 13B primers targeting the kinetoplastid DNA (kDNA) region. The samples found positive by PCR were typed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis using LITSR and L5.8S primers targeting internal transcribed spacer (ITS-1) region. Of the 50 smear samples, 17 (34%) were determined positive with 13A, 13B primers targeting the kinetoplastid DNA (kDNA) region. Positive samples were also found to be positive with LITSR and L5.8S primers targeting ITS-1 region. The PCR products obtained from PCR with ITS-1 gene region were digested with the restriction endonucleases BsuRI (HaeIII). As a result of PCR-RFLP analysis, it was determined that 11 of Leishmania tropica, one of Leishmania major and five of Leishmania infantum/donovani out of 17 samples. Chronic CL can be confused with skin diseases such as sarcoidosis, tuberculosis, malignant tumors. In particular, chronic CL cases can be escaped the attention for many reasons such as failure to diagnose correctly, insufficient microscope experience, fail to see due to low number of parasites. For this reason, it was concluded that PCR, which is a molecular method, should be used in chronic suspected CL samples which are negative for the parasite by microscopic examination.