Evaluation of six different DNA extraction methods for detection of Mycobacterium tuberculosis by means of PCR-IS6110: preliminary study

BACKGROUND: Developments in molecular detection and strain differentiation of members of Mycobacterium tuberculosis complex have proved to be useful. The DNA extraction method influences the amplification efficiency, causing interference on the sensitivity and respective inhibitors. The aim of this study was to standardize a simple and fast DNA extraction method, providing DNA amplification by IS6110-PCR effectively free from undue interferences. FINDINGS: The efficiency of the six different protocols tested in M. tuberculosis cultures has varied from 75% to 92.5%. This preliminary study evaluating the IS6110 PCR sensitivity and specificity was developed in DNA extracted from microscope slides, and achieved 100% of efficiency. CONCLUSIONS: DNA extraction by Chelex + NP-40 method from both, cultures of M. tuberculosis and smear slides, resulted in good quantity of interference free DNA, especially in samples with low concentrations of genetic material; therefore, such technique may be used for the molecular diagnosis of tuberculosis

Association of outcomes with comprehension, adherence and behavioral characteristics of tuberculosis patients using fixed-dose combination therapy in Contagem, Minas Gerais, Brazil

The present study aimed to assess the association of outcomes with comprehension, adherence and behavioral characteristics of tuberculosis (TB) patients using fixed-dose combination (FDC) therapy in the city of Contagem, MG, Brazil. This study used standardized questionnaires to collect data. Outcomes included cure in 77.2% (64/ 83), noncompliance with treatment in 20.4% (17/ 83), and absence of organ failure or death cases. The rate of adherence to treatment was high (71.1% - 59/ 83), while the level of comprehension of the treatment was insufficient for the majority of patients (72.3% - 60/ 83). When a greater number of medicines was used, the chance of noncompliance with treatment increased exponentially (p = 0.00 - OR 1.72). Light-skinned black patients, alcoholics and those who live with HIV/ AIDS showed a significant association with noncompliance with treatment (p=0.039 - OR 3.38, p=0.002 - OR 4.68, and p=0.001 - OR 9.68, respectively). Comprehension also presented a significant association with noncompliance with treatment (p=0.01 and OR 5.76 and CI 1.49-22.29). The probability of noncompliance with treatment in the first few months was greater than in the subsequent months. This study demonstrates that if the TB patients had a better understanding of the treatment, the outcome would have been more favorable as regards a proper cure

Diagnóstico de resistência do Mycobacterium tuberculosis à rifampicina utilizando-se da reação em cadeia da polimerase

The resistance of Mycobacterium tuberculosis to tuberculostatic drugs has emerged as a major public health threat. The resistance to rifampicin which has been attributed to structural changes in RNA polymerase can be considered as a marker for multi-drug-resistance to tuberculosis (MDR-TB). Patients bearing rifampicin-resistant strains have poor diagnosis even with treatment. Conventional culture-based drug sensibility testing can require several weeks due to the growth. In this paper we describe the most common PCR-based methods for detection of mutations that lead to rifampicin resistance, such as Single-Strand Conformation Polymorphism (SSCP), PCR Heteroduplex and INNO-LIPA. Recently, by Low Stringency using a Single Specific Primer (LSSP) assay, it was standardized a protocol that showed to be rapid and sensitive for the detection of mutations in the rpoB gene.A resistência do Mycobacterium tuberculosis aos tuberculostáticos tem surgido como grande ameaça à Saúde Pública. A resistência à rifampicina pode ser considerada como um marcador para a multi-resistência a fármacos e tem sido atribuída a mudanças estruturais da RNA polimerase, produto de expressão do gene rpoB. Os pacientes portadores dessas cepas têm baixa perspectiva frente ao tratamento. Os testes convencionais de sensibilidade aos fármacos realizados em cultura do Mtb requerem várias semanas para o crescimento. Por este motivo, a Reação em Cadeia da Polimerase (PCR), método de baixo custo e que pode reduzir o tempo para o diagnóstico, representa alternativa viável e promissora. Neste artigo estão descritos os métodos mais comumente empregados na detecção de mutantes resistentes à rifampicina baseados na PCR, como análise de Polimorfismo Conformacional de Fita Simples (Single-Strand Conformation Polymorphism, SSCP), PCR Heteroduplex e INNO-LIPA. Recentemente, padronizou-se a técnica de PCR em baixa estringência, usando um único iniciador (Low Stringency Single Specific Primer, LSSP), que se mostrou um método rápido e sensível na detecção de mutações no gene rpoB

Post-Biopsy Complications Associated with Percutaneous Kidney Biopsy

Renal physiology and physiopathology have been the object of studies aimed at developing exams that can assist in the early diagnosis of the base disease. Chronic kidney disease consists of the progressive, irreversible loss of kidney function. Early detection and appropriate treatment can minimize the progression of the disease, lower the inherent costs, and improve the quality of life of affected individuals. Kidney biopsy is the key method in this evaluation, as it enables the histological and immunohistochemical analysis of specimens in a fast, safe, and economical manner. The main indications for kidney biopsy are nephrotic syndrome, acute kidney failure of unknown etiology, persistent hematuria and proteinuria, chronic kidney disease with conserved kidney dimensions, and transplanted kidneys (to evaluate stages of rejection, infection, and/or sclerosis). However, as an invasive method, kidney biopsy is not without complications. Post-biopsy complication rates range from 5 to 15%, with 6.6% considered minor (macrohematuria with no need for blood transfusion) and another 7.7% considered major (hemorrhage requiring blood transfusion or other approaches). In this chapter, we address the main aspects of kidney biopsy, the technical procedures for its execution, and the management of the main complications stemming from this procedure

Evaluation of the commercial kit SIRE Nitratase for detecting resistant Mycobacterium tuberculosis in Brazil

This study was supported by the Minas Gerais State Research Support Foundation (FAPEMIG) protocol number 65/10 and the National Council for Scientific and Technological Development [Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)] protocol number 310174/2014-7-CNPQ.Universidade Federal de Minas Gerais. Faculdade de Medicina. Grupo de Pesquisa em Micobactérias. Belo Horizonte, MG, Brasil.Universidade Federal de Minas Gerais. Faculdade de Medicina Grupo de Pesquisa em Micobactérias. Belo Horizonte, MG, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Universidade Federal de Minas Gerais. Faculdade de Medicina Grupo de Pesquisa em Micobactérias. Belo Horizonte, MG, Brasil.Universidade Federal de Minas Gerais. Faculdade de Medicina Grupo de Pesquisa em Micobactérias. Belo Horizonte, MG, Brasil.Universidade Federal do Rio de Janeiro. Programa Acadêmico de Tuberculose. Rio de Janeiro, RJ, Brasil.Universidade Federal de Minas Gerais. Faculdade de Farmácia. Belo Horizonte, MG, Brasil.Universidade Federal de Minas Gerais. Consultoria e Apoio Técnico. Belo Horizonte, MG, Brasil.Introduction: This study aimed to evaluate a new commercial kit, Kit SIRE Nitratase-PlastLabor, for testing the drug susceptibility of clinical Mycobacterium tuberculosis isolates. Methods: The accuracy of the Kit SIRE Nitratase was evaluated by examining the susceptibility (streptomycin, isoniazid, rifampicin, and ethambutol) of 40 M. tuberculosis isolates, using the proportion method with Lowenstein-Jensen medium or the BACTEC MGIT 960 system. Results: The detection accuracy for streptomycin, isoniazid, rifampicin, and ethambutol was 95%, 97.5%, 100%, and 80%, respectively. Conclusions: The exceptional accuracy demonstrated by Kit SIRE Nitratase for isoniazid and rifampicin makes the kit an attractive option for screening M. tuberculosis strain resistance