Evaluation and improvement of two PCR targets in molecular typing of clinical samples of Leishmania patients (original) (raw)
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PCR diagnosis and characterization of Leishmania in local and imported clinical samples
Diagnostic Microbiology and Infectious Disease, 2003
Leishmaniasis diagnosis in regions where multiple species exist should identify each species directly in the clinical sample without parasite culturing. The sensitivity of two PCR approaches which amplify part of the ssu rRNA gene and the ribosomal internal transcribed spacer (ITS), respectively, was determined using human and dog blood seeded with Leishmania promastigotes. ssu-rDNA-PCR was more sensitive than ITS1-PCR, however species identification was not possible by the former approach. When a nested ITS1-PCR was used its sensitivity equaled the ssu-rDNA-PCR. Digestion of ITS1 amplicon with the restriction enzyme HaeIII distinguished all medically relevant Leishmania species. ITS1-PCR was used to diagnose 162 local and imported suspected cases of leishmaniasis in Israel, the Palestinian Authority and Germany. 113 cases (69.7%) were positive by PCR and species identification was possible in 110 samples. Leishmania DNA was also amplified and identified at the species level from archived non-stained and Giemsa stained microscope slides.
PubMed, 2021
Background: Leishmaniasis is a vector-borne disease caused by an intracellular protozoan parasite called Leishmania spp. Different species produce different clinical outcomes; the majority of cases are cutaneous forms. Leishmania major is one of the main causative agents of cutaneous leishmaniasis (CL). Various methods are being using to diagnose CL, including microscopic examination, culture, and molecular detection of the parasite genome. Method: In the current study, we tried to compare three common molecular markers, including Kinetoplast DNA (kDNA), Cytochrome b (Cyt b), and Internal transcribed space 1 (ITS1), for the detection of Leishmania major. After cultivation of standard strain of L. major MHOM/IR/75/ER in RPMI 1640, certain number of promastigotes was subjected to DNA extraction and different PCR reactions. Results: The lowest number of the parasite (5 promastigotes) can be detected by kDNA-PCR, followed by Cyt b-PCR (10 promastigotes), and ITS1-PCR (50 promastigotes). Conclusion: In conclusion, kDNA-PCR was the most sensitive marker and may provide more reliable data in the initial screening, especially in false-negative results provided by parasitological methods due to the low number of parasites.
Single step polymerase chain reaction (PCR) for the diagnosis of the Leishmania (Viannia) subgenus
Revista do Instituto de Medicina Tropical de São Paulo, 2004
In Brazil, the main etiologic agent of Leishmaniasis that frequently presents with mucosal involvement belongs to the Viannia subgenus. The therapeutic conduct in this disease depends on the parasitological diagnosis, and classical methods are restricted in identifying the agent. In this paper we describe a polymerase chain reaction (PCR), which uses primers designed from mini-exons repetitive sequences. The PCR amplifies a 177bp fragment that can distinguish (Viannia) from (Leishmania) subgenus. This test could be a useful diagnostic tool.
This study evaluated the applicability of kDNA-PCR as a prospective routine diagnosis method for American tegumentary leishmaniasis (ATL) in patients from the Instituto de Infectologia Emílio Ribas (IIER), a reference center for infectious diseases in São Paulo -SP, Brazil. The kDNA-PCR method detected Leishmania DNA in 87.5% (112/128) of the clinically suspected ATL patients, while the traditional methods demonstrated the following percentages of positivity: 62.8% (49/78) for the Montenegro skin test, 61.8% (47/76) for direct investigation, and 19.3% (22/114) for in vitro culture. The molecular method was able to confirm the disease in samples considered negative or inconclusive by traditional laboratory methods, contributing to the final clinical diagnosis and therapy of ATL in this hospital. Thus, we strongly recommend the inclusion of kDNA-PCR amplification as an alternative diagnostic method for ATL, suggesting a new algorithm routine to be followed to help the diagnosis and treatment of ATL in IIER. INTRODUCTION American tegumentary leishmaniasis (ATL) presents different clinical manifestations in Latin America, including mucosal leishmaniasis (ML), cutaneous localized leishmaniasis (CL), disseminated leishmaniasis (LCD), and diffuse leishmaniasis (DCL). These manifestations are caused by seven different species of Leishmania: Leishmania (Leishmania) amazonensis, L. (Viannia) braziliensis, L. (V.) guyanensis, L. (V.) lainsoni, L. (V.) naiffi, L. (V.) lindenberg, and L. (V.) shawi 7,24 .
2021
To perform PCR from serum for the diagnosis of visceral leishmaniasis is convenient and much less invasive than the examination of deeper compartments such as bone marrow. We compared three Leishmania-specific real-time PCRs with three different molecular targets (kinetoplast DNA, the small subunit-ribosomal RNA-(ssrRNA-)gene, the glucose-6-phosphate isomerase-(gpi-)gene) regarding their sensitivity and specificity in human serum. Residual sera from previous diagnostic assessments at the German National Reference Center for Tropical Pathogens Bernhard Nocht Institute for Tropical Medicine Hamburg and the Swiss Tropical and Public Health Institute were used. The sensitivities of kinetoplast DNA-PCR, ssrRNA-gene PCR, and gpi-PCR were 93.3%, 73.3%, and 33.3%, respectively, with 15 initial serum samples from visceral leishmaniasis patients, as well as 9.1%, 9.1%, and 0.0%, respectively, with 11 follow-up serum samples taken at various time points following anti-leishmanial therapy. Spec...
Un ensayo de PCR para identificar especies de Leishmania del subgénero Viannia
Rev. Soc. Ven. Microbiol, 2011
We have identified a novel DNA sequence of 500 bp (β500-DNA) on the Leishmania (Viannia) subgenus, located in the intergenic region of one of the loci of the β-tubulin gene family. The sequence analysis showed that this sequence has no homology to any other sequence described so far, including the β-tubulin gene. We improved a specific β500-PCR assay, which generated a PCR product of 375 bp for total genomic DNA from Leishmania strains belonging to the L. (Viannia) subgenus. In contrast, no amplification was found when using genomic DNA from species of L. (Leishmania) subgenus or other organisms. Under our PCR conditions, the lower detection limit was 1 fg when a purified DNA clone (pLgβ4), which contains one copy of the β500-DNA sequence, was used. The β500-DNA PCR assay confirmed the preliminary diagnosis of cutaneous leishmaniasis in clinical samples in which the Montenegro skin test was positive and parasite cultures were negative. The analytical specificity and the sensitivity of the PCR assay provide a tool for epidemiological studies of the disease.
Journal of Clinical Microbiology, 2003
We recently developed a new PCR-restriction fragment length polymorphism (RFLP)-based assay using the miniexon sequence from the genus Leishmania. Here we report the application of this new genotyping method to naturally infected clinical samples for the differentiation of New and Old World Leishmania species. Of the newly developed assay and four currently applied diagnostic tests (i.e., in vitro cultivation, serology, and two other molecular assays using either the small subunit-internal transcribed spacer sequence or a repetitive genomic sequence), the miniexon assay showed the highest sensitivity, 89.7%, compared to 70.6, 57.1, 51.7, and 79.3%, respectively. Species differentiation was robust and reliable compared with that by two other Leishmania genotyping techniques. The assay provides a valuable tool for the identification of Leishmania directly from clinical samples and enables determination of the infecting species by a facile technique with high discrimination power. Since Leishmania causes a broad spectrum of diseases distinguished by different parasite and host factors, detection and characterization of the infecting species is crucial for the confirmation of a diagnosis as well as the establishment of the clinical prognosis and the initiation of an adequate therapeutic approach. The miniexon PCR-RFLP assay will facilitate such determination and might improve diagnosis and treatment of leishmaniasis.
Leishmania aethiopica: Development of specific and sensitive PCR diagnostic test
Experimental Parasitology, 2011
a b s t r a c t PCR has proved useful for rapid diagnosis and typing of Leishmania. Lack of specificity to discriminate between species and/or sensitivity to detect from clinical samples has always been an issue. Previously developed primers either require PCR-RFLP analysis for Leishmania aethiopica discrimination or lack sensitivity to detect L. aethiopica from clinical samples. Here we report the development and validation of L. aethiopica specific PCR primers (V5F/V10R) based on cysteine protease B (cpb), a multicopy and polymorphic gene of Leishmania. V5F/V10R primers differentiate L. aethiopica from Leishmania tropica, Leishmania major, Leishmania donovani and Leishmania infantum by direct PCR. In addition, they are sensitive enough to detect L. aethiopica from biopsy samples. The primers can be very useful for epidemiological studies, species typing and diagnosis of L. aethiopica directly from clinical samples. Implementation of these primers in routine L. aethiopica diagnosis can improve detection rate, save time, money and labor required for culturing Leishmania.
Usefulness of PCR method for detection of Leishmania in Poland
Polish journal of microbiology / Polskie Towarzystwo Mikrobiologów = The Polish Society of Microbiologists, 2009
Leishmania parasites are the etiological agents of leishmaniosis, with severe course and often fatal prognosis, and the global number of cases has increased in recent decades. The gold standards for the diagnosis of leishmaniosis are microscopic examinations and culture in vitro of the different clinical specimens. The sensitivity of these methods is insufficient. Recent development in specific and sensitive molecular methods (PCR) allows for detection as well as identification of the parasite species (subspecies). The aim of the study was to estimate the usefulness of molecular methods (PCR) for detection of Leishmania species and consequently for the implementation of such methods in routine diagnostics of leishmaniosis in Polish patients returning from endemic areas of the disease. In our investigations we used 54 known Leishmania positive DNA templates (from culture and clinical specimens) received from the CDC (Atlanta, GA, USA). Moreover, 25 samples of bone marrow, blood or ot...