Use of the polymerase chain reaction for the diagnosis of asymptomatic Leishmania infection in a visceral leishmaniasis-endemic area.

The diagnosis of asymptomatic infection with Leishmania (Leishmania) chagasi has become more important over recent years. Expansion of visceral leishmaniasis might be associated with other routes of transmission such as transfusion, congenital or even vector transmission, and subjects with asymptomatic infection are potential reservoirs. Moreover, the identification of infection may contribute to the management of patients with immunosuppressive conditions (HIV, transplants, use of immunomodulators) and to the assessment of the effectiveness of control measures. In this study, 149 subjects living in a visceral leishmaniasis endemic area were evaluated clinically and submitted to genus-specific polymerase chain reaction (PCR), serological testing, and the Montenegro skin test. Forty-nine (32.9%) of the subjects had a positive PCR result and none of them developed the disease within a follow-up period of three years. No association was observed between the results of PCR, serological and skin tests. A positive PCR result in subjects from the endemic area did not indicate a risk of progression to visceral leishmaniasis and was not associated with a positive result in the serological tests.

USE OF THE POLYMERASE CHAIN REACTION FOR THE DIAGNOSIS OF ASYMPTOMATIC Leishmania INFECTION IN A VISCERAL LEISHMANIASIS-ENDEMIC AREA / Uso da reação em cadeia da polimerase para o diagnóstico de infecção assintomática por Leishmania em área endêmica de leishmaniose visceral

The diagnosis of asymptomatic infection with Leishmania (Leishmania) chagasi has become more important over recent years. Expansion of visceral leishmaniasis might be associated with other routes of transmission such as transfusion, congenital or even vector transmission, and subjects with asymptomatic infection are potential reservoirs. Moreover, the identification of infection may contribute to the management of patients with immunosuppressive conditions (HIV, transplants, use of immunomodulators) and to the assessment of the effectiveness of control measures. In this study, 149 subjects living in a visceral leishmaniasis endemic area were evaluated clinically and submitted to genus-specific polymerase chain reaction (PCR), serological testing, and the Montenegro skin test. Forty-nine (32.9%) of the subjects had a positive PCR result and none of them developed the disease within a follow-up period of three years. No association was observed between the results of PCR, serological and skin tests. A positive PCR result in subjects from the endemic area did not indicate a risk of progression to visceral leishmaniasis and was not associated with a positive result in the serological tests.

O diagnóstico de infecção assintomática por Leishmania (Leishmania) chagasi tem assumido crescente importância nos últimos anos. A expansão da leishmaniose visceral pode estar associada a outras vias de transmissão tais como transfusional, congênita, ou mesmo vetorial, sendo os indivíduos com infecção assintomática, potenciais reservatórios. Ademais, a identificação da infecção poderia auxiliar na condução dos pacientes com condições de imunossupressão (HIV, transplante, uso de imunomoduladores) e na avaliação da efetividade das medidas de controle. Neste estudo, foram avaliados clinicamente 149 indivíduos residentes em área endêmica de leishmaniose visceral e realizada a reação em cadeia da polimerase (PCR) gênero-específica, testes sorológicos e teste de Montenegro. Destes, 49 (32,9%) apresentaram PCR positiva, dos quais nenhum evoluiu com clínica de leishmaniose visceral nos três anos subsequentes. Não houve associação entre o resultado da PCR, dos exames sorológicos e do teste cutâneo. A positividade da PCR em indivíduos da área endêmica estudada não indicou risco de progressão para leishmaniose visceral e também não foi associada à maior positividade dos testes sorológicos.

Sensitivity and reproducibility of a PCR assay for Leishmania detection using skin biopsy imprints on filter paper.

The sensitivity and reproducibility of a PCR targeted to amplify the conserved 120 base-pair region of minicircles from Leishmania kDNA was defined using DNA extracted from skin biopsy imprints on filter paper. Seventy-seven patients with cutaneous leishmaniasis from an endemic region of Leishmania (Viannia) braziliensis in Brazil underwent skin biopsy of the ulcer border. Tissue samples were imprinted on filter paper and then, they were stored at -20 degrees C. Imprints on filter paper were stored at 4 degrees C. Samples were processed at three laboratories; Lab1 and Lab2 performed the PCR-kDNA assay using DNA extracted from the filter paper, and Lab3 processed PCR-kDNA using DNA from fresh-frozen tissue used as a gold standard. All samples were codified to maintain blinding during lab processing. Fifty-three (68.8%) patients had parasites isolated and identified by isoenzymes as L. (V.) braziliensis. The positivity of PCR-kDNA was similar between the three laboratories: 87.0, 85.7 and 88.3% (Lab1, Lab2 and Lab3, respectively). The sensitivity of PCR-kDNA in culture-proven cases was better, and showed similar results in all laboratories: 95.8, 95.8 and 97.9% (Lab1, Lab2 and Lab3, respectively). Data from the 77 enrolled patients showed an overall percent agreement of 80.5% (Kappa=0.173) for the filter-paper approach between Lab1 and Lab2. Percent agreement between Lab1 and Lab3 was 83.1% (Kappa=0.22), and it was 94.8% between Lab2 and Lab3 (Kappa=0.77). Fifteen patients were diagnosed in just one of the two laboratories that used DNA extracted from filter paper. We conclude that the sensitivity of the filter paper approach is satisfactory and could be used in clinical trials and field work. Reproducibility could be improved using two separate imprints from the same biopsy sample.

Implantação do Sistema de Gestão da Qualidade em um laboratório de pesquisa do Instituto Oswaldo Cruz (IOC): desafios e soluções da realidade do Programa PALC (Programa de Acreditação de Laboratórios Clínicos) da SBPC/ML (Sociedade Brasileira de Patologia Clínica – Medicina Laboratorial) / Implementation of the System of Quality Management in a research laboratory of the Oswaldo Cruz Institute (IOC): challenges and solutions of reality PALC Program (Accreditation Program for Clinical Laboratories) SBPC / ML (Brazilian Society of Pathol

No mundo moderno e globalizado em que vivemos atualmente, objeto de profundas e aceleradas transformações tanto políticas, sociais quanto econômicas, estratégias diferenciadas e criativas para elevar a qualidade de seus produtos e serviços têm sido adotadas regularmente. Para atingir este patamar de transformações com oportunidades estratégicas, é preciso iniciar um programa que promova a implantação de novas formas de gestão da organização, baseado no controle da qualidade e na educação continuada, no sentido de enfrentar novos desafios e provocar mudanças, principalmente cultural das pessoas envolvidas no processo. Baseado nestas exigências, o Laboratório de Epidemiologia Molecular de Doenças Infecciosas (LEMDI), do Instituto Oswaldo Cruz (IOC) – Fiocruz se propôs a buscar um certificado de acreditação, com a implantação de um sistema da qualidade, para mostrar credibilidade e confiabilidade de seus resultados, melhorando o desempenho de suas atividades e aumentando as expectativas de seus clientes internos e externos. Escolheu a norma PALC (Programa de Acreditação de Laboratórios Clínicos) da SBPC/ML (Sociedade Brasileira de Patologia Clínica - Medicina Laboratorial) por suas regras de abordagem mais técnica e menos processual, o que condiz melhor com a realidade de um laboratório de pesquisa, uma vez que até o presente momento não existe norma específica para acreditação de laboratórios de pesquisas. A metodologia utilizada nesta dissertação foi a de auditorias internas sucessivas para avaliar os requisitos da norma PALC aplicáveis à realidade de um laboratório de pesquisas e a elaboração de plano de ação para acompanhar o avanço da implementação do processo e corrigir as não-conformidades...

In modern and globalized world in which we live today, that is an object ofprofound and accelerated political, social and economic changes, diverse and creative strategies to raise the quality of its products and services have been taken regularly. To achieve this level of change along with strategic opportunities, we must begin a program that promotes the development of new ways in managing the organization. Theground work features are quality control and ongoing education programs that meet new challenges and lead cultural changes particularly to the people involved in such process. Based on these requirements, the Laboratory of Molecular Epidemiology of Infectious Diseases (LEMDI), at the Oswaldo Cruz Institute (IOC) – Fiocruz proposed to apply for accreditation and started to implement a quality system in order to show credibility and reliability of its results. This could definitely bring improvements to the laboratory activity performance and increase the expectations of its internal and externalcustomers. LEMDI has chosen the Clinical Laboratory Accreditation Program (PALC) norm from the Brazilian Society for Clinical Pathology/Laboratory Medicine (SBPC /ML) as a reference because it contains more technical and less procedural approach rules. Moreover, this methodology meets better with the reality of research laboratories. Hitherto, there is no specific standard for accreditation of such type of laboratory. The methodology used in this thesis involves successive internal audits to assess the requirements of the standard PALC norm applicable to the reality of a research laboratory. It also addresses the development of an action plan to monitor the implementation progress of the series of actions (changes) and correct the nonconformities...

Leishmania (Viannia): genetic analysis of cutaneous and mucosal strains isolated from the same patient.

Ten pairs of Leishmania (Viannia) strains isolated from mucosal and cutaneous lesions of the same patient were analyzed genotypically in order to determine whether populations that had metastasized to mucosal sites differed from those in the cutaneous lesion. The strains were previously characterized by multi locus enzyme electrophoresis and/or monoclonal antibodies reactivity, and, for this study, only isolates from the same patient which were identified as the same species were employed. PCR-RFLP of internal transcribed spacer (ITS) rDNA, random amplified polymorphic DNA (RAPD), and schizodeme analyses were conducted. All genotyping methods revealed microheterogeneity between cutaneous and mucosal isolates from the same patient. The PCR-RFLP of the ITS rDNA and RAPD analysis were numerically analyzed through similarity coefficients and dendrograms were generated. All phenograms clustered cutaneous and mucosal strains of the same patient in one branch with a high degree of similarity, and phenetic analysis matched between them. Schizodeme analysis revealed differences between strains that composed some pairs. Genetic analyses indicate that some populations that metastasize to mucosal sites are distinguishable from the population in cutaneous lesions, however, other approaches will be required to associate genetic polymorphisms with the cutaneous or mucosal phenotype of strains.

Biological parameters and molecular markers of clone CL brener - the reference organism of the Trypanosoma cruzi genome project

Clone CL Brener is the reference organism used in the Trypanosma cruzi Genome Project. Some biological paramenters of CL Brener were determined: (a) the doubling time of epimastigote forms cultured in liver infusion-tryptose (LIT) medium at 28ºC is 58ñ13 hr; (b) differentiation of epimastigotes to metacyclic trypomastigotes is obtained by incubation in LIT-20 per cent Grace's medium; (c) trypomastigotes infect mammalian cultured cells and perform the complete intracellular cycle at 33 and 37ºC; (c) blood forms are highly infective to mice; (e) blood forms are susceptible to nifurtimox and benznidazole. The molecular typing of CL Brener has been determined: (a) isoenzymatic profiles are characteristic of zymodeme ZB; (b) PCR amplification of a 24 alpha ribosomal RNA sequence indicates it belongs to T. cruzi lineage 1; (c) schizodeme, randomly amplified polymorphic DNA (RAPD) and DNA fingerprinting analyses were performed.

An improved silver staining procedure for schizodeme analysis in polyacrylamide gradient gels

A simple protocol is described for the silver staining of polyacrylamide gradient gels used for the separation of restriction fragments of kinetoplast DNA [schizodeme analysis of trypanosomatids (Morel et al., 1980)]. The method overcomes the problems of non-uniform staining and strong background color which are frequently encountered when conventional protocols for silver staining of linear gels. The method described has proven to be of general applicability for DNA, RNA and protein separations in gradient gels