Avaliação do desempenho de um teste rápido imunocromatográfico no diagnóstico de hanseníase em uma região endêmica no norte do Brasil / Evaluation of the performance of a rapid immunochromatographic test in the diagnosis of leprosy in an endemic region in northern Brazil

Introdução: A hanseníase é de grande importância para a saúde pública, devido à sua epidemiologia e a seu poder incapacitante. A eficiência no diagnóstico desta doença é limitada. O objetivo deste estudo foi o de analisar o desempenho de um teste rápido imunocromatográfico para hanseníase multibacilar (MB) e paucibacilar (PB), em amostras positivas e negativas pela baciloscopia de raspado dérmico em pacientes diagnosticados com hanseníase, comparando analiticamente com os critérios da Organização Mundial da Saúde (OMS). Métodos: O estudo foi realizado no município de Ji-Paraná/RO, entre 2015 e 2016, sendo avaliados 140 indivíduos. A análise comparativa entre os métodos foi realizada pelo cálculo de sensibilidade e especificidade utilizando o software SPSS®. Foi estimado o índice de Kappa (k) para avaliação da concordância entre os métodos. Valores de p <0,05 foram considerados significativos. Resultados: O índice de concordância entre o teste rápido e a classificação da OMS foi de k= 0,94 (p <0,01). Quando comparado a baciloscopia de indivíduos com hanseníase PB e o teste rápido, foi verificada concordância não significante (k= 0,01; p= 0,59). Comparando a concordância entre a baciloscopia de indivíduos com hanseníase MB e o teste rápido, foi detectado um índice de k= 0,64 (p <0,01). Além disso, sensibilidade de 94% e especificidade de 98% foram detectadas para hanseníase PB. Para hanseníase MB a sensibilidade foi de 95% e a especificidade de 98%. Conclusão: O teste rápido avaliado é uma ferramenta útil, rápida e eficaz no auxílio do diagnóstico da hanseníase. (AU)

Introduction: Leprosy is of great importance for public health because of its epidemiology and disabling power. Efficiency in the diagnosis of this disease is limited. The objective of this study was to evaluate the performance of a rapid immunochromatographic test for multibacillary (MB) and paucibacillary (BP) leprosy, in positive and negative samples by skin smear examination in patients with leprosy, and to compare the rapid test analytically with World Health Organization (WHO) criteria. Methods: The study was conducted in the municipality of Ji-Paraná/RO, Brazil, between 2015 and 2016. In total, 140 individuals were evaluated. For a comparative analysis of the methods, sensitivity and specificity were calculated using SPSS® software. The Kappa (k) index was used to evaluate agreement between the methods. A p-value < 0.05 was considered significant. Results: Regarding agreement between the rapid test and WHO classification, k index was 0.94 (p < 0.01). When skin smear of individuals with BP leprosy was compared to the rapid test, agreement was non-significant (k = 0.01; p = 0.59). For agreement between skin smear of individuals with MB leprosy and the rapid test, a k index of 0.64 (p < 0.01) was detected. In addition, for PB leprosy sensitivity was 94% and specificity was 98%, while for MB leprosy sensitivity was 95% and specificity was 98%. Conclusion: The rapid test is a useful tool, fast and effective in aiding the diagnosis of leprosy. (AU)

Estudo piloto de avaliação de um teste rápido imunocromatográfico para o diagnóstico de sífilis gestacional / Pilot evaluation of a rapid immunochromatographic test for the diagnosis of gestational syphilis

A sífilis gestacional é um problema global de saúde pública e é uma das mais comuns causas de efeitos adversos durante a gravidez devido à ausência ou inadequação do tratamento. Estabelecer um diagnóstico de sífilis durante o pré-natal, evita a transmissão de Treponema pallidum para a criança. Objetivo: o objetivo deste estudo foi avaliar o desempenho de OL Syphilis (OrangeLife, Brasil), um teste imunocromatográfico rápido, para o diagnóstico de sífilis gestacional. Métodos: Um total de 185 mulheres grávidas no pré-natal foram avaliadas por sífilis OL. Os resultados foram comparados com os métodos tradicionais: Laboratório de Pesquisa de Doenças Venéreas e Reaginas de Plasma Rápido (VDRL e RPR) como ensaios de seleção e FTA-ABS como teste confirmatório. Resultados: A prevalência de sífilis nessa população foi de 6,49% (IC 3,40 a 11,06%). A sensibilidade do teste rápido (TR) foi de 91,67% (IC95% 61,52 a 99,79%) e a especificidade foi de 100% (95%IC 97,89 a 100%). O PPV foi 100% (95%CI 71,51 a 100%) e o VPL foi de 99,43 (95%CI 96,84 a 100%). O acordo medido pelo coeficiente Kappa foi de 0,954 (IC95% 0,863 a 1,000). Conclusão: O teste OL Syphilis poderia ser usado no rastreio de mulheres grávidas, fornecendo diagnóstico rápido, aumentando a probabilidade de ter a doença diagnosticada e oportuna, evitando as consequências devastadoras da sífilis congênita.

Gestational syphilis is a global public health problem and one of the most common causes of adverse effects during pregnancy due to absence or inadequacy of treatment. Establishing a diagnosis of syphilis during prenatal care prevents the transmission of Treponema pallidum to the child. Objective: The objective of this study was to evaluate the performance of OL Syphilis (OrangeLife, Brazil), a rapid immunochromatographic test for gestational syphilis diagnosis. Methods: A total of 185 pregnant women in prenatal care were evaluated by OL Syphilis. The results were compared by traditional methods: Venereal Disease Research Laboratory and Rapid Plasma Reagin (VDRL and RPR) for screening and fluorescent treponemal antibody absorption test (FTA-Abs) for confirmation. Results: The prevalence of syphilis in this population was 6.49% (95%CI 3.40 to 11.06%). Rapid Test (RT) sensitivity was 91.67% (95%CI 61.52 to 99.79%) and specificity was 100% (95%CI 97.89 to 100%). Positive predictive value was 100% (95%CI 71.51 to 100%) and Negative predictive value was 99.43% (95%CI 96.84 to 100%). The agreement measured by Kappa coefficient was 0.954 (95%CI 0.863 to 1.000). Conclusion: The OL Syphilis test could be used for screening pregnant women, thus providing rapid diagnosis, increasing the probability of diagnosis and timely treatment, and preventing the devastating consequences of congenital syphilis.

Prevalence of hepatitis C virus and human immunodeficiency virus in a group of patients newly diagnosed with active tuberculosis in Porto Alegre, Southern Brazil

BACKGROUND Porto Alegre is the Brazilian state capital with second highest incidence of tuberculosis (TB) and the highest proportion of people infected with human immunodeficiency virus (HIV) among patients with TB. Hepatitis C virus (HCV) infection increases the risk of anti-TB drug-induced hepatotoxicity, which may result in discontinuation of the therapy. OBJECTIVES The aim of this study was (i) to estimate prevalence of HCV and HIV in a group of patients newly diagnosed with active TB in a public reference hospital in Porto Alegre and (ii) to compare demographic, behavioural, and clinical characteristics of patients in relation to their HCV infection status. METHODS One hundred and thirty-eight patients with TB were tested for anti-HCV antibody, HCV RNA, and anti-HIV1/2 antibody markers. HCV RNA from real-time polymerase chain reaction (PCR)-positive samples was submitted to reverse transcription and PCR amplification. The 5′ non-coding region of the HCV genome was sequenced, and genotypes of HCV isolates were determined. FINDINGS Anti-HCV antibody, HCV RNA, and anti-HIV antibodies were detected in 27 [20%; 95% confidence interval (CI), 13-26%], 17 (12%; 95% CI, 7-18%), and 34 (25%; 95% CI, 17-32%) patients, respectively. HCV isolates belonged to genotypes 1 (n = 12) and 3 (n = 4). Some characteristics were significantly more frequent in patients infected with HCV. Among them, non-white individuals, alcoholics, users of illicit drugs, imprisoned individuals, and those with history of previous TB episode were more commonly infected with HCV (p < 0.05). MAIN CONCLUSIONS HCV screening, including detection of anti-HCV antibody and HCV RNA, will be important to improving the management of co-infected patients, given their increased risk of developing TB treatment-related hepatotoxicity.

Performance of a molecular assay to detect Mycobacterium tuberculosis complex DNA in clinical specimens: multicenter study in Brazil

BACKGROUND In high tuberculosis (TB) burden countries, there are few data on the performance of new molecular commercialised assays developed locally. OBJECTIVE To evaluate the performance of a new molecular commercialised assay for TB diagnosis (Detect-TB) in three laboratories. METHODS A total of 302 sputum samples from an equal number of patients with presumptive diagnosis of pulmonary tuberculosis (PTB) were submitted for routine smear microscopy, culture, and Detect-TB assay at three different sites in Brazil (the cities of Caxias do Sul, São Paulo and Canoas). FINDINGS Seventy four (24.7%) TB cases were diagnosed (65 bacteriologically confirmed). When compared to smear microscopy/culture results, the overall sensitivity and specificity of Detect-TB assay was 84.6% (CI 95%; 73.7-91.6) and 93.1% (CI 95%; 89.1-95.8), respectively. When compared to bacteriological and clinical diagnostic criteria, the sensitivity and specificity of Detect-TB assay was 74.3% (CI 95%; 63.3-82.9) and 92.9% (CI 95%; 88.7-95.6), respectively. Among the three sites - Caxias do Sul, São Paulo and Canoas - the sensitivity and specificity were respectively 94.7% and 97.8%; 71.4% and 93.9%, 82.1% and 88.9%. MAIN CONCLUSIONS These findings suggest that the Detect-TB assay could be applied routinely in reference laboratories across different regions in Brazil.

Novas tecnologias para estudo da tuberculose: uma análise da detecção e transmissão de M. tuberculosis circulante / New technologies for the study of tuber culosis: an analysis of the detection and transmission of circulating M. tuberculosis

Além de identificar os doentes com tuberculose (TB), é importante monitorar os genótipos de M. tuberculosis circulantes. Mesmo após a implantação do Xpert® MTB/RIF, o diagnóstico é ainda realizado apenas pela baciloscopia, que apresenta baixa sensibilidade, na maioria dos laboratórios. OBJETIVO: Utilizar análises de DNA para o diagnóstico e identificação dos genótipos circulantes em uma população do Rio Grande do Sul, Brasil. METODOLOGIA: Amostras clínicas foram analisadas pelo Detect-TB (Labtest,MG), por PCR em tempo real (Xpert® MTB/RIF) e comparados a baciloscopia. A genotipagem foi realizada por spoligotyping. RESULTADOS: A acurácia do Detect-TB para a identificação da TB foi similarao Xpert® MTB/RIF, sendo que o Detect-TB foi mais custo-efetivo quando utilizado em conjunto com a baciloscopia. Os genótipos LAM5, RDRio e like-Pinni2, relacionados a resistência ao tratamento, estavam sendo transmitidos neste grupo, e a maioria dos resistentes a isoniazida (78,5%)e dos resistentes a rifampicina (92,1%) apresentavam as mutações mais conhecidas. CONCLUSÃO: A aplicação de tecnologias de DNA pode auxiliar no controle de TB, tanto no diagnóstico rápido quanto na identificação de perfis resistentes, viabilizando tratamento adequado aos pacientes.

In addition to detecting patients with tuberculosis (TB), it is important tomonitor circulating M. tuberculosis genotypes. Even after the implantation of Xpert® MTB/RIF, the diagnosis is still based only by bacilloscopy, which have a low sensitivity, in most laboratories. OBJECTIVE: To use DNA analysis for diagnosis and identification of circulating genotypes in a population of Rio Grande do Sul, Brazil. METHODOLOGY: Clinical samples were analyzed by Detect-TB (Labtest,MG), real-time PCR (Xpert® MTB/RIF) and compared to bacilloscopy. Genotyping was performed by spoligotyping. RESULTS: The accuracy of Detect-TB was similar to Xpert® MTB / RIF, butDetect-TB was more cost-effective when used with bacilloscopy. The genotypesLAM5, RDRio and like-Pinni2, related to treatment resistance, were being transmitted among this group, and the majority of the resistant to isoniazid (78.5%) and the resistant to rifampicin (92.1%) presented themost known mutations. CONCLUSION: The application of DNA technologies can help in the controlof TB, both in rapid diagnosis and in the identification of resistant profiles, allowing adequate treatment to the patients.

In house reverse membrane hybridisation assay versus GenoType MTBDRplus and their performance to detect mutations in the genes rpoB, katG and inhA

Drug-resistant tuberculosis (TB) threatens global TB control and is a major public health concern in several countries. We therefore developed a multiplex assay (LINE-TB/MDR) that is able to identify the most frequent mutations related to rifampicin (RMP) and isoniazid (INH) resistance. The assay is based on multiplex polymerase chain reaction, membrane hybridisation and colorimetric detection targeting of rpoB and katG genes, as well as the inhA promoter, which are all known to carry specific mutations associated with multidrug-resistant TB (MDR-TB). The assay was validated on a reference panel of 108 M. tuberculosis isolates that were characterised by the proportion method and by DNA sequencing of the targets. When comparing the performance of LINE-TB/MDR with DNA sequencing, the sensitivity, specificity and agreement were 100%, 100% and 100%, respectively, for RMP and 77.6%, 90.6% and 88.9%, respectively, for INH. Using drug sensibility testing as a reference standard, the performance of LINE-TB/MDR regarding sensitivity, specificity and agreement was 100%, 100% and 100% (95%), respectively, for RMP and 77%, 100% and 88.7% (82.2-95.1), respectively, for INH. LINE-TB/MDR was compared with GenoType MTBDRplus for 65 isolates, resulting in an agreement of 93.6% (86.7-97.5) for RIF and 87.4% (84.3-96.2) for INH. LINE-TB/MDR warrants further clinical validation and may be an affordable alternative for MDR-TB diagnosis.

Colorimetric microwell plate reverse-hybridization assay for Mycobacterium tuberculosis detection

Direct smear examination using Ziehl-Neelsen staining for pulmonary tuberculosis (PTB) diagnosis is inexpensive and easy to use, but has the major limitation of low sensitivity. Rapid molecular methods are becoming more widely available in centralized laboratories, but they depend on timely reporting of results and strict quality assurance obtainable only from costly commercial kits available in high burden nations. This study describes a pre-commercial colorimetric method, Detect-TB, for detecting Mycobacterium tuberculosis DNA in which an oligonucleotide probe is fixed onto wells of microwell plates and hybridized with biotinylated polymerase chain reaction amplification products derived from clinical samples. The probe is capable of hybridising with the IS6110 insertion element and was used to specifically recognise the M. tuberculosis complex. When combined with an improved silica-based DNA extraction method, the sensitivity of the test was 50 colony-forming units of the M. tuberculosis reference strain H37Rv. The results that were in agreement with reference detection methods were observed in 95.2 percent (453/476) of samples included in the analysis. Sensitivity and specificity for 301 induced sputum samples and 175 spontaneous sputum samples were 85 percent and 98 percent, and 94 percent and 100 percent, respectively. This colorimetric method showed similar specificity to that described for commercially available kits and may provide an important contribution for PTB diagnosis.

In house colorimetric reverse hybridisation assay for detection of the mutation most frequently associated with resistance to isoniazid in Mycobacterium tuberculosis

Mutations in the katG gene have been identified and correlated with isoniazid (INH) resistance in Mycobacterium tuberculosis isolates. The mutation AGC→ACC (Ser→Thr) at katG315 has been reported to be the most frequent and is associated with transmission and multidrug resistance. Rapid detection of this mutation could therefore improve the choice of an adequate anti-tuberculosis regimen, the epidemiological monitoring of INH resistance and, possibly, the tracking of transmission of resistant strains. An in house reverse hybridisation assay was designed in our laboratory and evaluated with 180 isolates of M. tuberculosis. It could successfully characterise the katG315 mutation in 100 percent of the samples as compared to DNA sequencing. The test is efficient and is a promising alternative for the rapid identification of INH resistance in regions with a high prevalence of katG315 mutants.

Tuberculose resistente: revisäo molecular / Resistant tuberculosis: a molecular review

O progresso na compreensäo dos mecanismos de resistência aos fármacos usados no tratamento da tuberculose tem permitido o desenvolvimento de novos métodos para a detecçäo da tuberculose resistente. A resistente aos fármacos representa uma ameaça para os programas de controle da tuberculose. Para tanto, é necessário conhecer o padräo de sensibilidade das linhagens para fornecer o tratamento adequado. Os estudos moleculares dos mecanismos de açäo dos fármacos antituberculose têm elucidado as bases genéticas da resistência aos fármacos em Mycobacterium tuberculosis. Os mecanismos de resistência aos fármacos na tuberculose säo causados por mutaçöes cromossomais em diferentes genes da bactéria. Durante a exposiçäo aos fármacos, há uma pressäo seletiva favorecendo o desenvolvimento de linhagens resistentes. A tuberculose multirresistente é um problema nacional e internacional que traz sérias dificuldades para o controle global da doença. Realizou-se uma revisäo sobre os mecanismos moleculares associados à resistência aos fármacos com ênfase nas novas perspectivas para detectar os isolados resistentes