Leishmania (Viannia) Species Identification on Clinical Samples from Cutaneous Leishmaniasis Patients in Peru: Assessment of a Molecular Stepwise Approach (original) (raw)

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.

Artículo original A PCR assay for the identification of Leishmania species of the Viannia subgenus

Revista de la Sociedad Venezolana …, 2011

A PCR assay for the identification of Leishmania species of the Viannia subgenus

We have identified a novel DNA sequence of 500 bp (B-500-DNA) on the Leishmania (Viannia) subgenus, located in the intergenic region of one of the loci of the B-tubulin gene family. The sequence analysis showed that this sequence has no homology to any other sequence described so far, including the B-tubulin gene. We improved a specific B-500-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 (pLgB4), which contains one copy of the B-500-DNA sequence, was used. The B-500-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 sensitiv...

Leishmania (Viannia) braziliensis identification by PCR in the state of Para, Brazil

Transactions of the Royal Society of Tropical Medicine and Hygiene, 2011

The incidence of cutaneous leishmaniasis (CL) is increasing and there is limited surveillance of Leishmania species throughout the world. We identified the species associated with CL in a region of Amazonia, an area recognized for its Leishmania species variability. Clinical findings were analyzed and correlated with the species identified in 93 patients. PCR assays were based on small subunit ribosomal DNA (SSU-rDNA) and G6PD, and were performed in a laboratory located 3,500 km away. Leishmania (V.) braziliensis was identified in 53 patients (57%). The other 40 patients (43%) carried a different species (including six cases of L. (L.) amazonensis). Molecular methods can be employed, using special media, to allow transport to distant laboratories. L. (V.) braziliensis is the most common species in the area of Para. The location of ulcers can suggest CL species

PCR-Based Diagnosis of Acute and Chronic Cutaneous Leishmaniasis Caused by Leishmania (Viannia)

Journal of Clinical Microbiology, 2002

We evaluated PCR methods for diagnosis of acute and chronic cutaneous leishmaniasis (CL) in an area of Colombia where Leishmania (Viannia) is endemic. The PCR method specifically amplified whole linearized minicircle kinetoplast DNA (kDNA) of the Leishmania subgenus Viannia from biopsy lysates. PCR products were detected in agarose gels. For 255 acute cases, this PCR method had greater sensitivity (75.7%) than each conventional method, i.e., microscopic examination of Giemsa-stained lesion scraping (46.7%), biopsy culture (55.3%), aspirate culture (46.3%), and the conventional methods combined (70.2%). Among 44 cases of chronic CL, amplification of biopsy DNA was more sensitive (45.5%) than the individual (4.5 to 27.7%) and combined (27.3%) conventional methods. The detection of kDNA in biopsies from chronic lesions was enhanced by a chemiluminescent dot blot hybridization, which produced a sensitivity of 65.8% when alone and 90.9% when in combination with DNA extraction of biopsy lysates (P < 0.001). Three biopsies from 84 skin lesions of other etiologies were falsely positive by PCR (specificity, 96.4%). PCR detected kDNA more frequently in biopsies (detection level, 83.9%) than in aspirates (74.7%) from 103 cases of acute CL. Among aspirates from 53 chronic cases of CL, the alternative methods, DNA extraction and hybridization, increased sensitivity from 41.5 to 56.6% (P > 0.05). This enhanced PCR method in chronic biopsies was so much more sensitive than conventional methods that it should be considered the preferred diagnostic method for chronic CL. These findings support the appropriate incorporation of PCR into diagnostic strategies for cutaneous leishmaniasis.