The polymerase chain reaction (PCR) and its variations, such as the nested-PCR, have been described as promising techniques for rapid diagnosis of tuberculosis (TB). With the aim of evaluating the usefulness of a nested-PCR method on samples of blood and urine of patients suspected of tuberculosis we analyzed 192 clinical samples, using as a molecular target the insertion element IS6110 specific of M. tuberculosis genome. Nested-PCR method showed higher sensitivity in patients with extrapulmonary tuberculosis (47.8% and 52% in blood and urine) when compared to patients with the pulmonary form of the disease (sensitivity of 29% and 26.9% in blood and urine), regardless of the type of biological sample used. The nested-PCR is a rapid technique that, even if not showing a good sensitivity, should be considered as a helpful tool especially in the extrapulmonary cases or in cases where confirmatory diagnosis is quite difficult to be achieved by routine methods. The performance of PCR-based techniques should be considered and tested in future works on other types of biological specimens besides sputum, like blood and urine, readily obtainable in most cases. The improving of M. tuberculosis nested-PCR detection in TB affected patients will give the possibility of an earlier detection of bacilli thus interrupting the transmission chain of the disease.

Bancroftian filariasis is a major public health problem in the city of Recife in north-eastern Brazil. In some of its urban areas microfilaraemia prevalence reaches 14%. This study describes epidemiological characteristics, infection and disease, in 2 urban areas, Coque and Mustardinha, before control measures were applied. The parasitological survey was performed by a 'door-to-door' census covering 5563 subjects, aged between 5 and 65 years. Microfilaraemia was detected by the thick drop technique, using 45 microL of peripheral blood collected between 20:00 and 24:00. In both areas the prevalence of microfilaraemia was 10%, and males had higher prevalences of infection and disease than females. The prevalence of microfilaraemia was higher in the 15-24 and 25-34 years age groups in both sexes. Most microfilaria (mf) carriers (72.1% in Coque and 79.7% in Mustadrinha) had mf densities < 100/60 microL of blood. Females of reproductive age had significantly lower mf densities than males. The overall disease prevalence in both areas was 6.3%. Amongst the subjects who presented with chronic disease 15.7% were microfilaraemic. Chronic disease prevalence increased from 1.4% in the 5-14 years age group to 11.3% in the oldest age group. The most frequent clinical manifestation was hydrocele (5.4%), followed by lymphoedema (1.8%). The epidemiological pattern of filariasis in the populations studied was marked by high prevalence of microfilaraemia, low mf density, and relatively low prevalence of filarial disease considering the level of endemicity.

HLA and other genetic variants, playing an important role in innate and adaptive immunity, are known to influence tuberculosis (TB) development in HIV-1-positive (HIV+) patients. Because inflammasome genes contribute to HIV-1 susceptibility, we investigated the possible association between polymorphisms in inflammasome genes with HIV-1 and Mycobacterium tuberculosis coinfection (HIV+TB+) in a case/control cohort of Brazilian individuals. Nineteen single-nucleotide polymoprhims in 8 inflammasome genes (NLRP1, NLRP3, AIM2, CARD8, CASP1, IL1B, IL1R, and HSP90) were analyzed in HIV+TB+ Brazilian patients (from Recife, Pernambuco). CARD8 rs6509365 polymorphism was associated with HIV+TB+ (P = 5 × 10(-5)), suggesting a predisposing role of this variant in M. tuberculosis susceptibility in HIV+ subjects (odds ratio = 2.45). This effect is even strong when this allele is combined to CARD8 rs2043211 single-nucleotide polymoprhim. The results of this study support the novel association between CARD8 gene and HIV+TB+ coinfection, demonstrating that inflammasome genetics could influence HIV-1 infection and the development of opportunistic infection.

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Introduction: Molecular analyses are auxiliary tools for detecting Koch's bacilli in clinical specimens from patients with suspected tuberculosis (TB). However, there are still no effi cient diagnostic tests that combine high sensitivity and specifi city and yield rapid results in the detection of TB. This study evaluated single-tube nested polymerase chain reaction (STNPCR) as a molecular diagnostic test with low risk of cross contamination for detecting Mycobacterium tuberculosis in clinical samples. Methods: Mycobacterium tuberculosis deoxyribonucleic acid (DNA) was detected in blood and urine samples by STNPCR followed by agarose gel electrophoresis. In this system, reaction tubes were not opened between the two stages of PCR (simple and nested). Results: STNPCR demonstrated good accuracy in clinical samples with no cross contamination between microtubes. Sensitivity in blood and urine, analyzed in parallel, was 35%-62% for pulmonary and 41%-72% for extrapulmonary TB. The specifi city of STNPCR was 100% in most analyses, depending on the type of clinical sample (blood or urine) and clinical form of disease (pulmonary or extrapulmonary). Conclusions: STNPCR was effective in detecting TB, especially the extrapulmonary form for which sensitivity was higher, and had the advantage of less invasive sample collection from patients for whom a spontaneous sputum sample was unavailable. With low risk of cross contamination, the STNPCR can be used as an adjunct to conventional methods for diagnosing TB.

O trabalho visou à otimização de um método baseado na reação em cadeia da polimerase multiplex - para diferenciação de micobactérias de interesse para a saúde pública. A PCR Multiplex baseou-se na amplificação simultânea do genehsp65, presente em todo gênero Mycobacterium, do gene dnaJ, presente apenas em Mycobacterium tuberculosis e Mycobacterium avium e da sequência de inserção IS6110 presente no complexo Mycobacterium tuberculosis, gerando amplicons de 165pb, 365pb e 541pb, respectivamente. O limite de detecção foi de 1fg para o alvo hsp65, 100pg para o dnaJ e 0,1fg para o IS6110. A PCR multiplex detectou até 100pg de DNA de Mycobacterium tuberculosis. O sistema demonstrou ser específico e sensível na detecção de Mycobacterium tuberculosis, Mycobacterium bovis, Mycobacterium avium e Mycobacterium smegmatis. Os resultados obtidos utilizando cepas de referência demonstraram que a PCR multiplex pode ser uma ferramenta rápida, sensível e específica na diferenciação de micobactérias.

Objective: To evaluate the performance of nested PCR (nPCR) in detecting the Mycobacterium tuberculosis complex in blood samples of patients suspected of having TB, in order to determine its potential for use as an auxiliary tool in the laboratory diagnosis of TB in children. Methods: Detection of the M. tuberculosis complex in blood samples using as a target the insertion sequence IS6110 of the genomic DNA of the bacillus. Blood samples of 120 patients were evaluated. All of the patients were under 15 years of age at the time of their treatment at public hospitals in the city of Recife, Brazil (between January of 2003 and August of 2005). Attending physicians at the hospitals diagnosed TB based on the criteria recommended by the American Thoracic Society. The nPCR amplified a 123-bp fragment with outer oligonucleotides (IS1/IS2) and, in the subsequent reaction, using inner oligonucleotides (IS3/IS4), generating an 81-bp amplicon. Results: Active or latent TB was found in 65 patients, TB was ruled out in 28 suspected cases, and 27 patients were TB-free (controls). The sensitivity of nPCR was 26.15% and was significantly higher for the extrapulmonary form of the disease (55.56%) than for the pulmonary form (18.18%). The specificity was 92.73%. Conclusions: Despite the difficulties in diagnosing TB in children and the low number of cases evaluated in the present study, nPCR in blood samples proved to be a rapid and specific technique, albeit one with low sensitivity. In order to establish its true usefulness in the diagnosis of paucibacillary forms, especially extrapulmonary TB, further studies need to be carried out with a larger sample of children and analyzing biological specimens other than blood.Keywords: Tuberculosis; Diagnosis; Blood; Polymerase chain reaction. ResumoObjetivo: Avaliar o desempenho da técnica nested PCR (nPCR) para detectar o complexo Mycobacterium tuberculosis em amostras de sangue de pacientes com suspeita de TB para sua possível utilização como uma ferramenta auxiliar no diagnóstico laboratorial da doença em crianças. Métodos: Detecção do complexo M. tuberculosis em amostras de sangue usando como alvo a sequência de inserção IS6110 do DNA genômico do bacilo. Foram avaliados 120 pacientes, menores de 15 anos de idade, de ambos os sexos, provenientes de hospitais públicos do Recife (PE), no período entre janeiro de 2003 e agosto de 2005. O diagnóstico de TB foi realizado pelo médico assistente do serviço de saúde de acordo com os critérios da Sociedade Torácica Americana. A nPCR amplificou um fragmento de 123 pb com oligonucleotídeos externos (IS1/IS2) e, na reação subsequente, com oligonucleotídeos internos (IS3/IS4), gerando um amplicon de 81 pb. Resultados: A TB ativa ou latente esteve presente em 65 pacientes, foi descartada em 28 suspeitos e 27 não tinham a doença (controles). A sensibilidade da nPCR foi de 26,15%, sendo significativamente maior na forma extrapulmonar (55,56%) em relação à pulmonar (18,18%), e a especificidade foi de 92,73%. Conclusões: Diante das dificuldades ...