Leishmania cytochrome b gene sequence polymorphisms in southern Iran: relationships with different cutaneous clinical manifestations

Clinical polymorphism of zoonotic cutaneous leishmaniasis: combination of the clinical and the parasitological diagnosis

Zoonotic cutaneous leishmaniasis (ZCL) is a neglected tropical disease caused by Leishmania (L.) major. This zoonosis is characterized by a broad-spectrum clinical polymorphism and may be underestimated and poorly treated since it is a simulator of various dermatoses. The aim of our study was to analyze the clinical polymorphism of patients with ZCL. A total of 142 patients with confirmed CL based on the microscopic examination of skin lesion biopsies were included in this study. Molecular typing of Leishmania species revealed that all patients were infected with L. major. In total, 14 clinical forms were observed. Six were typical and eight were atypical. The typical ZCL forms are grouped as follows: papular (26.76%), ulcero-crusted (26.05%), ulcerated (13.38%), impetiginous (9.86%), nodular (9.15%), and papulo-nodular (5.63%) lesions. In atypical ZCL forms, we described erythematous (2.81%), erysipeloid (1.4%), sporotrichoid, (1.4%), keratotic (0.7%) lupoid (0.7%), lichenoid (0.7%), psoriasiform (0.7%), and zosteriform (0.7%) lesions. Here, the lichenoid and the keratotic forms caused by L. major were reported for the first time in Tunisia. These findings will help physicians to be aware of the unusual lesions of ZCL that could be confused with other dermatological diseases. For this reason, it will be necessary to improve the diagnosis of CL especially in endemic areas. Such large clinical polymorphism caused by L. major may be the result of a complex association between the vector microbiota, the parasite, and the host immune state, and further studies should be carried out in order to reveal the mechanisms involved in clinical polymorphism of ZCL.

The Association of Human Leucocyte Antigen (HLA) Class I and II Genes with Cutaneous and Visceral Leishmaniasis in Iranian Patients: A Preliminary Case-Control Study

Background

Leishmaniasis is currently considered a re-emerging or emerging infection based on the geographic region. The outcome of leishmaniasis vastly depends on Leishmania-host interaction. This preliminary study aimed to show the association of human leukocyte antigen (HLA) class I and II genes with healed and non-healed cutaneous leishmaniasis (CL), and symptomatic and asymptomatic visceral leishmaniasis (VL) compared with control groups in Iran.

Methods

Ninety-five people, including 31 patients versus 64 individuals in the control group, were enrolled. Among them, 20 patients had confirmed CL based on amastigote observation, 10 had improved CL and 10 non-healed CL. Eleven patients were suffering from confirmed VL based on direct agglutination test (Five asymptomatic and six symptomatic VL cases). Besides, they were residents in an endemic area of VL in the northwest of Iran. To select a control group, it was ensured that they had no history of leishmaniasis. Peripheral blood samples were collected from each patient. After DNA extraction, HLA typing was conducted using polymerase chain reaction - sequence-specific priming (PCR-SSP). Subsequently, data were statistically analyzed by SPSS.

Results

There was a statistical relationship between the presence of HLA-A26 and CL, healed CL and the existence of the B38 allele, C1 allele and symptomatic VL, as well as B1.4 allele and asymptomatic VL (P<0.05).

Conclusion

This primary finding indicates that several HLA genes have a potential role in the susceptibility of Iranian people to CL and VL.

Genetic diversity of Leishmania major strains isolated from Phlebotomus papatasi and Phlebotomus alexandri in western Iran based on minicircle kDNA

This study aimed to screen the natural infection rate of Leishmania major in Phlebotomus papatasi and Phlebotomus alexandri in two counties (Mehran and Dehloran) of Ilam province as cutaneous leishmaniasis endemic areas in the west of Iran. Furthermore, the genetic diversity of parasite species that are isolated from vectors, was investigated. Sandflies were collected by sticky traps from May 2018 to October 2018. Afterward, specimens were prepared for species identification by morphological features. DNA was extracted from female sandflies, and minicircle kDNA was used to identify Leishmania isolates through nested-PCR, followed by genetic diversity between Leishmania isolates was investigated by sequence analysis of the amplified minicircle kDNA. Natural infection of the L. major was shown in all positive specimens using nested-PCR. Analysis of data from 14 isolates displayed a high level of genetic diversity in L. major. In the phylogenetic trees, all of the L. major isolates occurred in six clusters. Clusters I, II, III, and VI contained isolated strains from P. papatasi. While clusters IV and V contained isolated strains from P. alexandri. Genetic diversity of L. major isolated from vectors was investigated in western Iran for the first time. According to the results of this study, probably "various clones of L. major populations are distributed in the study area.

The Geographical Distribution of Human Cutaneous and Visceral Leishmania Species Identified by Molecular Methods in Iran: A Systematic Review With Meta-Analysis

Leishmaniasis is one of the most common vector-borne parasitic diseases in Iran. Leishmania species identification is necessary for epidemiological aspects, precise prognosis, control and treatment of the disease. We systematically searched all the studies, reports, and documentation related to species identification and geographical distribution of causative agents of cutaneous (CL), mucosal (ML), and visceral leishmaniasis (VL) using DNA-based molecular diagnostic techniques in Iran. International databases including PubMed, ScienceDirect, Embase, Google Scholar, Scopus, and Web of Science were systemically searched for English articles and Iran's databases including SID, IranMedex and Magiran were searched for Persian reports and articles. Searches were performed from 1999 to 2019 (20 years). The current review was conducted using the keywords: cutaneous leishmaniasis, visceral leishmaniasis, Leishmania species, Human, Molecular, PCR, and Iran. The study quality was evaluated using the NOS checklist. This meta-analysis procedure was accomplished using STATA, version 2.7.9. Of the 3,426 records identified in the initial search, 154 articles met inclusion criteria and qualified for the systematic review and meta-analysis. In subgroup analysis, the pooled frequency of causative agents of CL isolates was 67.3% (95% CI: 59.51–74.67%) for L. major and 32.1% (95% CI: 24.72–39.87%) for L. tropica. In addition, the pooled frequency of causative agents of VL isolates was 97.1% (95% CI: 94.6–98.8%) for L. infantum and 2.9% (95% CI: 1.12–5.37%) for L. tropica. The findings of this study showed that the main causative agents of CL and VL in Iran are L. major and L. infantum, respectively. Moreover, kinetoplast DNA (kDNA) and internal transcriber spacer (ITS) were the most used markers for identifying Leishmania species. The current study provides valuable data to encourage and direct researchers as well as public health managers in the comprehensive leishmaniasis control and prevention planning in Iran.

Evaluation of cytochrome b sequence to identify Leishmania species and variants: the case of Panama

BACKGROUND

The genetic heterogeneity of Leishmania parasites is a major factor responsible for the wide variety of Leishmania-associated manifestations. Consequently, understanding the genetic make-up of Leishmania species using suitable molecular markers is an important component of realising local and regional scale disease risk. The cytochrome b (cytb) is frequently used to type New World Leishmania species. However, its potential to discriminate Leishmania species and variants requires further evaluation.

OBJECTIVES

To explore the capacity of cytb gene to identify New World Leishmania species and variants and to develop an approach able to type local Leishmania species and variants.

METHODS

We retrieved 360 partial and complete Leishmania cytb gene sequences publicly available in GenBank database to study all single nucleotide polymorphisms (SNPs) across the cytb gene that differentiate New World Leishmania species. This information was used to develop an approach based upon the polymorphisms found in a DNA segment of 948bp. We also compared the typing results found with this technique with the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) profiling obtained using HSP70 gene as target. One hundred Panamanian isolates were used to both typed Leishmania species and assess local genetic variability.

FINDINGS

We found complete agreement between our cytb approach and the PCR-RFLP profiling method based on HSP70 for Leishmania species identification. Ninety-two isolates were identified as L. panamensis, although other Viannia species were found circulating at a lower frequency. Three L. panamensis haplotypes were identified in Panamanian provinces. We also provide an initial report of L. guyanensis haplotypes circulating in Panama.

MAIN CONCLUSIONS

Cytb gene sequence encompasses key main SNPs that aid to identify Leishmania species. The cytb approach developed with this information was able to identify and assess genetic variability of local Leishmania species found in this study.

Molecular characteristic of treatment failure clinical isolates of Leishmania major

Background

Leishmaniasis is a prevalent tropical disease caused by more than 20 Leishmania species (Protozoa, Kinetoplastida and Trypanosomatidae). Among different clinical forms of the disease, cutaneous leishmaniasis is the most common form, with an annual 0.6–1 million new cases reported worldwide. This disease’s standard treatment is pentavalent antimonial (Sb^V) that have been used successfully since the first half of the 20th century as a first-line drug. However, treatment failure is an increasing problem that is persistently reported from endemic areas. It is important to define and standardize tests for drug resistance in cutaneous leishmaniasis. Sb^V must be reduced to its trivalent active form (Sb^III). This reduction occurs within the host macrophage, and the resultant Sb^IIIenters amastigotes via the aquaglyceroporin1 (AQP1) membrane carrier. Overexpression of AQP1 results in hypersensitivity of the parasites to Sb^III, but resistant phenotypes accompany reduced expression, inactivation mutations, or deletion of AQP1. Hence, in this study, a phylogenetic analysis using barcode gene COXII and kDNA minicircle and expression analysis of AQP1 were performed in treatment failure isolates to assess the isolates’ molecular characteristics and to verify possible association with drug response.

Methods

Samples in this study were collected from patients with cutaneous leishmaniasis referred to the Diagnosis Laboratory Center in Isfahan Province, Iran, from October 2017 to December 2019. Among them, five isolates (code numbers 1–5) were categorized as treatment failures. The PCR amplification of barcode gene COXII and kDNA minicircle were done and subsequently analyzed using MEGA (10.0.5) to perform phylogenetics analysis of Treatment failures (TF) and Treatment response (TR) samples. Relative quantification of the AQP1 gene expression of TF and TR samples was assessed by real-time PCR.

Results

All samples were classified as L. major. No amplification failure was observed in the cases of barcode gene COXII and kDNA minicircle amplification. Having excluded the sequences with complete homology using maximum parsimony with the Bootstrap 500 method, four major groups were detected to perform phylogenetic analysis using COXII. The phylogenetic analysis using the barcode target of minicircle showed that all five treatment failure isolates were grouped in a separate sub-clade.

Conclusions

We concluded that the barcode gene COXII and the minicircle kDNA were suitable for identification, differentiation and phylogenetic analysis in treatment failure clinical isolates of Leishmania major. Also, AQP1 gene expression analyses showed that treatment failure isolates had less expression than TR isolates. The isolate with TF and overexpression of the AQP1 gene of other molecular mechanisms such as overexpression of ATP-binding cassette may be involved in the TR, such as overexpression of ATP-binding cassette which requires further research.

[New aspects in the histopathology of infectious skin diseases]

BACKGROUND

An infectious pathogenesis should always be considered in inflammatory infiltrates in the skin. While some organisms can be recognized on hematoxylin-eosin staining (e.g. yeasts, leishmania), histochemical and immunohistochemical stainings are available for others.

OBJECTIVES

If no organisms are seen in a section, the diagnosis of an infection cannot be made with surety, but the pattern of the inflammatory infiltrate can still be suggestive of an infectious process. New or little-known reaction patterns and difficulties in differential diagnosis will be demonstrated.

MATERIALS AND METHODS

Selective literature review and analysis of individual cases.

RESULTS

Studies using molecular techniques to identify organisms in biopsy specimens have helped to better characterize the histomorphological spectrum of skin infiltrates in infectious skin diseases. Apart from unusual herpes simplex and varicella zoster infections, the histopathology of coxsackie virus and measles exanthem, borreliosis, syphilis, and of cutaneous leishmaniasis is demonstrated. For numerous organisms, molecular tests have been established that can be used on the formalin-fixed, paraffin-embedded material.

CONCLUSIONS

Selected skin infections demonstrate the broad histomorphological spectrum of skin infiltrates induced by infectious organisms. It is important for histopathologists to know which reaction pattern requires them to alert the clinician to necessary ancillary diagnostics (culture, serology) and when to consider molecular diagnostics to be performed on the biopsy specimen.

Multilocus sequence typing analysis of Leishmania clinical isolates from cutaneous leishmaniasis patients of Iran

Cutaneous leishmaniasis (CL) is mainly caused by L. major and L. tropica in Old World and might be represented as typical skin lesion(s) or sometimes as a spectrum of atypical manifestations. We applied multilocus sequence typing (MLST) to explore genetic variations of Leishmania strains isolated from atypical vs. typical CL patients from Iran. A PCR-sequencing was performed for seven housekeeping genes (g6pd, mpi, asat, icd, 6pgd, fh, and trys) and genetic diversity indices and phylogenetic relationships were analyzed. A total of 41 isolates of L. major (28/41) and L. tropica (13/41) from 21 (51.2%) atypical CL and 20 (48.8%) typical CL cases were included. A set of additional sequences of 41 strains of 17 species of Leishmania were retrieved from databases. Different SNP variations were detected and the highest rate of heterozygous sites was found in g6pd and 6pgd genes (6 sites) for L. tropica and in asat and 6pgd genes (7 sites) for L. major strains. All strains were clustered into 58 unique sequence types (STs) including 17 STs related to 41 strains of Leishmania of this study. Concatenated tree clustered all strains in 6 main clades (A to F) including L. major (clade D) and L. tropica (clade B) strains. Two strains of L. major (codes 28 and 42) with highest nucleotide variations were more close to L. tropica and were grouped in Clade B. All of the STs were related in clonal complexes by using eBURST with the prediction of founder genotypes. A high rate of genetic variations and heterozygocity was evident in L. tropica and L. major strains; nevertheless, there was no significant difference in the diversity of Leishmania strains between typical CL and atypical CL groups. This study represents the first successful application of MLST approach to L. tropica and L. major strains in Iran.