Phylogenetic study of treatment failure clinical isolates of Leishmania major

Abstract Background: Molecular characteristics are necessary for designing programs for the control, prevention, and treatment against cutaneous leishmaniasis. In the present study, treatment failure (TF) clinical isolates of Leishmania major were phylogenetically analyzed using the barcode genes of cytochrome oxidase II (COXII) and 13A/B. Methods: Samples were collected from 126 patients referred to the Diagnosis Laboratory Center from October 2017 to December 2019. All TF cases were assessed using COXII and 13A/B, and phylogenetic analysis was created using BLASTn, T-COFFEE, and MEGA 7.0.21. Results: All 126 isolates were L. major, in which 5 isolates were TF. All isolates had successfully amplified by the specific primer for COXII region. The alignment analysis with all the 5 TF isolates and the standard Friedlin strain showed more than 98% similarity. Phylogenetic analysis with 13A/B showed that all 5 TF isolates are clustered in one group, although phylogenetic analysis showed different clustering after comparison of 5 TF isolates with 16 TR isolates and the same regions in other isolates in GenBank, NCBI. Conclusions: All 21 isolates studied in this study, comprising TF and TR isolates, were clustered in near groups. However, 13A/B could differentiate the 5 TF isolates from selected 6 TR isolates, completely.