[Determination of Leishmania species by PCR-RFLP in the smear samples taken from the lesions of cutaneous leishmaniasis cases]

Abstract

The forms of the disease caused by Leishmania species in Turkey as well as in Aegean region are cutaneous and visceral leishmaniasis (CL and VL, respectively), and the agent of CL is commonly L.tropica. However, L.infantum was also reported as being CL agent recently. Direct microscopic examination, serological tests and culture are the conventional methods used for the diagnosis of CL. Since the specificities of these methods are high their sensitivities are variable and identification at species level is not possible. Recently, the use of polymerase chain reaction (PCR)-based molecular methods enabled the rapid and reliable diagnosis and species identification. The aim of this study was to investigate the performance of PCR-restriction fragment length polymorphism (RFLP) method both for the detection and identification of Leishmania species simultaneously in CL patients. A total of 30 smear samples that were positive for Leishmania amastigotes with microscopic examination, obtained from CL-suspected cases admitted to Adnan Menderes University Medical School Hospital, Parasitology Laboratory (located at Aydin, in the Aegean region of Turkey) between 2012-2014 period were included in the study. Ten samples taken from the skin lesions caused by Staphylococcus aureus (n= 5) and Candida albicans (n= 5) were also included as negative controls. DNA extractions from the smears were performed by the use of a commercial kit (Macherey-Nagel NucleoSpin Tissue® Kit, Germany). DNA isolation was also performed from L.major, L.infantum and L.tropica promastigotes that were grown in culture as positive controls. In PCR method LITSR and L5.8S primers targeting to ITS (internal transcribed spacer)-1 region were used. In RFLP method, the amplified PCR products were cleaved by BsuRI (HaeIII) restriction enzyme for the species identification. As a result, restriction profiles of all samples (n= 30) were in accordance with L.tropica restriction profile. No band was observed in the control samples (n= 10). The data of this study showed that the most common CL agent in Aydin is L.tropica. In conclusion, ITS-1 PCR-RFLP method may be used directly as a single routine procedure for both the detection and identification of Leishmania species in the clinical samples of CL patients, in laboratories with adequate facilities.