Pathogenesis of Secondary Pulmonary Tuberculosis and Role of Cord Factor in Secondary Infection / 中国医学科学院学报

The primary and secondary tuberculosis features two completely different pathogenesis.At present,the pathogenesis of primary tuberculosis has been clear,whereas that of secondary tuberculosis remains unclear.In order to decipher the mechanism of secondary infection of

Estrategias alternativas para el diagnóstico de tuberculosis: una opción para los pacientes paucibacilares / alternative strategies for the tuberculosis diagnosis: an option for paucibacillary patients

el diagnóstico de la tuberculosis ha estado basado en la detección directa de la micobacteria; sin embargo, se estima que este se puede lograr solamente en el 10% de los casos y requiere que se combine con métodos confirmatorios como el cultivo, el cual puede tomar varias semanas para que el crecimiento sea evidente. Los métodos basados en la amplificación de la secuencia ácidos nucleicos muestran sensibilidad y especificidad altas, pero no siempre son accesibles a todos los laboratorios debido a sus requerimientos de infraestructura y el costo de los insumos. Las limitaciones para el diagnóstico hacen que se busque continuamente metabolitos micobacterianos, mediante diferentes aproximaciones, que sean, ulteriormente, fáciles de rastrear en condiciones muy básicas de laboratorio. En esta revisión se incluyen algunas de las aproximaciones metodológicas basadas en la detección de derivados micobacterianos y su valor como herramienta para el rastreo de la micobacteria

The diagnosis of tuberculosis has been based on the direct detection of mycobacteria. However, it is estimated that only can be achieved in 10% of the cases and it is necessary to combine with confirmatory methods such as culture that may take several weeks to growth been evident. Methods based on sequence amplification of nucleic acids show high sensitivity and specificity, but are not always accessible to all laboratories due to infrastructure requirements and the cost of inputs. The limitations for the diagnosis induce to a continued research for mycobacterial metabolites by different approaches that are later easy to trace in very basic laboratory conditions. This review includes some of the methodological approaches based on mycobacterial derivatives and their value as a tool to detect the mycobacteria

Desempenho da cultura líquida MGIT após implementação em uma rede de laboratórios públicos do estado de São Paulo / Performance of liquid culture MGIT after implementation in a network of public laboratories of Sao Paulo state

A OMS, em 2007, recomendou a implementação da cultura líquida para o diagnóstico da tuberculose (TB) e teste de sensibilidade para países de baixa e média renda. Neste estudo foi avaliado odesempenho da cultura líquida MGIT em condição de rotina após dois anos de implantação em uma rede de laboratórios públicos. Foi efetuada análise retrospectiva de dados da cultura líquida,realizadas em dez laboratórios regionais do Instituto Adolfo Lutz, de janeiro a março de 2010. Foram incluídas amostras submetidas a baciloscopia, cultura líquida MGIT automatizada ou manual eidentificação presuntiva do complexo Mycobacterium tuberculosis (CMTB). Foram detectadas 1.159 culturas positivas. Destas, 113 (9,7%) contaminaram, e 1.046 foram analisadas, sendo 850 (81,3%) CMTB, 116 (11,1%) micobactérias não tuberculosas e 6 (0,6%) Nocardia sp. A taxa de contaminação foi de 2,2% e o acréscimo da cultura para o diagnóstico da TB foi de 29,9%. A média do tempo de detecção da cultura foi de 14,7 dias (DP+/- 11,7 dias). A acurácia da identificação presuntiva foide 91,3%. A cultura líquida MGIT demonstrou ser excelente alternativa para efetuar diagnóstico da TB e das micobacterioses, em razão da rapidez possibilitando uma intervenção rápida e eficaz no tratamento.

In 2007, WHO recommended the implementation of liquid culture for tuberculosis (TB) diagnosis anddrug-susceptibility test in low and middle-income countries. This study evaluated the performanceof MGIT culture in routine condition after two years of its implementation in a public laboratoriesnetwork. This is a retrospective study, which analyzed the data on the liquid culture performed in ten regional laboratories of the Institute Adolfo Lutz, from January to March 2010. The data included clinical samples submitted to microscopy, automated or manual MGIT culture and presumptive M. tuberculosis complex (MTBC) identification by analyzing the cord formation. Culture waspositive in 1,159 samples. Of these, 113 (9.7%) contaminated, and 1,046 were analyzed, of which 850 (81.3%) were identified as MTBC, 116 (11.1%) as non-tuberculous mycobacteria and 6 (0.6%)as Nocardia sp. Contamination rate was 2.2% and the contribution of culture to the TB diagnosis was 29.9%. The detection mean time was 14.7 days (SD+/-11.7 days). The accuracy of the presumptive identification of MTBC was 91.3%. MGIT liquid culture demonstrated to be an excellent alternative for diagnosing TB and mycobacterioses, because of the rapidity of diagnosis, thus allowing an immediate and effective treatment.

Desempenho da cultura líquida MGIT após implementação em uma rede de laboratórios públicos do estado de São Paulo / Performance of liquid culture MGIT after implementation in a network of public laboratories of Sao Paulo state

A OMS, em 2007, recomendou a implementação da cultura líquida para o diagnóstico da tuberculose (TB) e teste de sensibilidade para países de baixa e média renda. Neste estudo foi avaliado o desempenho da cultura líquida MGIT em condição de rotina após dois anosde implantação em uma rede de laboratórios públicos. Foi efetuada análise retrospectiva de dados da cultura líquida, realizadas em dez laboratórios regionais do Instituto Adolfo Lutz, de janeiro a março de 2010. Foram incluídas amostras submetidas a baciloscopia, cultura líquida MGIT automatizada ou manual e identificação presuntiva do complexo Mycobacterium tuberculosis (CMTB). Foram detectadas 1.159 culturas positivas. Destas, 113 (9,7%) contaminaram, e 1.046 foram analisadas, sendo 850 (81,3%) CMTB, 116 (11,1%) micobactérias não tuberculosas e 6 (0,6%) Nocardia sp A taxa de contaminação foi de 2,2% e o acréscimo da cultura para o diagnóstico da TB foi de 29,9%. A média do tempo de detecção da cultura foi de 14,7 dias (DP+/- 11,7 dias). A acurácia da identificação presuntiva foi de 91,3%. A cultura líquida MGIT demonstrou ser excelente alternativa para efetuar diagnóstico da TB e das micobacterioses, em razão da rapidez possibilitando uma intervenção rápida e eficaz no tratamento.

In 2007, WHO recommended the implementation of liquid culture for tuberculosis (TB) diagnosis and drug-susceptibility test in low and middle-income countries. This study evaluated the performance of MGIT culture in routine condition after two years of its implementation in a public laboratories network.This is a retrospective study, which analyzed the data on the liquid culture performed in ten regional laboratories of the Institute Adolfo Lutz, from January to March 2010. The data included clinical samples submitted to microscopy, automated or manual MGIT culture and presumptive M. tuberculosis complex (MTBC) identification by analyzing the cord formation. Culture was positive in 1,159 samples. Of these, 113 (9.7%) contaminated, and 1,046 were analyzed, of which 850 (81.3%) were identified as MTBC, 116 (11.1%) as non-tuberculous mycobacteria and 6 (0.6%) as Nocardia sp. Contamination rate was 2.2% and the contribution of culture to the TB diagnosis was 29.9%. The detection mean time was 14.7 days (SD+/-11.7 days). The accuracy of the presumptive identification of MTBC was 91.3%. MGIT liquid culture demonstrated to be an excellent alternative for diagnosing TB and mycobacterioses, because of the rapidity of diagnosis, thus allowing an immediate and effective treatment.

Cord factor detection and macroscopic evaluation of mycobacterial colonies: an efficient combined screening test for the presumptive identification of Mycobacterium tuberculosis complex on solid media / Detecção do fator corda e avaliação do aspecto macroscópico das colônias de micobactérias: um eficiente teste de triagem combinado para a identificação presuntiva do complexo Mycobacterium tuberculosis em meios só

OBJECTIVE: The rapid differentiation between Mycobacterium tuberculosis and nontuberculous mycobacteria is fundamental for patients co-infected with tuberculosis and HIV. To that end, we use two methods in our laboratory: detection of cord factor and PCR-restriction enzyme analysis (PRA). The objective of this study was to evaluate the accuracy of a screening test on solid medium as a rapid method for the presumptive identification of M. tuberculosis complex, considering costs and turnover time. METHODS: A total of 152 strains were submitted to a combined screening test, consisting of the detection of cord factor under microscopy (Ziehl-Neelsen staining) and evaluation of the macroscopic aspect of colonies, as well as to PRA, which was used as the gold standard. Costs were estimated by calculating the price of all of the materials needed for each test. RESULTS: The overall accuracy of cord factor detection alone was 95.4 percent (95 percent CI: 90.7-98.1 percent), and that of the combined screening test was 99.3 percent (95 percent CI: 96.4-100 percent). Cord factor detection costs US$ 0.25, whereas the PRA costs US$ 7.00. Results from cord factor detection are ready in 2 days, whereas PRA requires 4 days to yield results. CONCLUSIONS: The presumptive identification of M. tuberculosis using the macroscopic evaluation of colonies combined with cord factor detection under microscopy is a simple, rapid and inexpensive test. We recommend the combined screening test to rapidly identify M. tuberculosis in resource-poor settings and in less well-equipped laboratories while awaiting a definite identification by molecular or biochemical methods.

OBJETIVO: A diferenciação rápida entre Mycobacterium tuberculosis e micobactérias não-tuberculosas é fundamental para os pacientes coinfectados com tuberculose e HIV. Para tanto, utilizamos duas metodologias em nosso laboratório: detecção do fator corda e PCR-restriction enzyme analysis (PRA). O objetivo do estudo foi avaliar a acurácia desse teste de triagem em meio sólido como um método rápido para a identificação presuntiva do complexo M. tuberculosis, considerando custos e tempo de resultado. MÉTODOS: Foram processadas 152 cepas pelo teste de triagem combinado, que consistiu da detecção do fator corda por microscopia (esfregaço corado por Ziehl-Neelsen) e avaliação do aspecto macroscópico das colônias, e PRA (padrão ouro). Os custos foram estimados através da obtenção dos preços dos insumos necessários para a realização de cada teste. RESULTADOS: A acurácia da detecção do fator corda foi de 95,4 por cento (IC95 por cento: 90,7-98,1 por cento) e a do teste de triagem combinado foi de 99,3 por cento (IC95 por cento: 96,4-100 por cento). O custo da detecção do fator corda foi de R$ 0,60 e do PRA de R$ 16,00. Os resultados da detecção do fator corda estão prontos em 2 dias, ao passo que os de PRA necessitam de 4 dias. CONCLUSÕES: A identificação presuntiva de M. tuberculosis usando o aspecto macroscópico das colônias em conjunto com a detecção de fator corda por microscopia é um teste simples, rápido e de baixo custo. Recomendamos o teste de triagem combinado para rapidamente identificar M. tuberculosis em sítios com poucos recursos financeiros e em laboratórios menos equipados, enquanto se aguarda a identificação definitiva por métodos moleculares ou bioquímicos.

Avaliação do crescimento em cordas na identificação presuntiva do complexo Mycobacterium tuberculosis / Detection of cord factor for the presumptive identification of Mycobacterium tuberculosis complex

OBJETIVO: O Mycobacterium tuberculosis, sob certas condições apropriadas, cresce em cordões de serpentinas, denominados de fator corda, ou crescimento em cordas. O objetivo deste estudo é avaliar a detecção do fator corda como método de identificação presuntiva do complexo M. tuberculosis, comparando-o aos testes de tipificação (TIP) convencionais. MÉTODO: Foram analisadas 743 cepas, de janeiro de 2002 a dezembro de 2005, na Área de Micobactérias do Instituto Adolfo Lutz - Santos, obtidas de isolados clínicos coletados de pacientes sintomáticos respiratórios ou com suspeita clínica de tuberculose pulmonar e/ou micobacterioses, atendidos nas Unidades Básicas de Saúde da Baixada Santista. Foram feitos esfregaços das cepas de micobactérias isoladas em meio líquido MB/BacT e meio sólido, Lowenstein-Jensen ou Ogawa-Kudoh, sendo 301 (40,5 por cento) cepas em meio líquido e 442 (59,5 por cento) em meio sólido. RESULTADOS: Os resultados de sensibilidade, especificidade e valores preditivos positivos e negativos, obtidos com a comparação do desempenho do método em ambos os meios de isolamento e TIP convencionais, foram respectivamente 98,5, 88, 97 e 93 por cento. Observou-se maior sensibilidade do método em meio sólido (100 por cento), com uma diferença de sensibilidade entre os meios analisados de apenas 2,7 por cento. CONCLUSÕES: Conclui-se, pelos resultados obtidos, que o fator corda é um critério real e rápido na identificação do complexo M. tuberculosis; além disso, em laboratórios com alta prevalência do complexo M. tuberculosis e que não dispõem de técnicas que permitam a precocidade de sua identificação, o fator corda possibilita o direcionamento aos testes conclusivos de identificação e adicionais de sensibilidade que se façam necessários.

OBJECTIVE: Virulent strains of the Mycobacterium tuberculosis complex, under certain appropriate conditions, grow as characteristic ropes, bundles or serpentine cords known as cord factor or growth in cords. The objective of the present study was to evaluate cord factor detection as a method of achieving presumptive identification of the M. tuberculosis complex, comparing it to conventional typing tests. METHODS: A total of 743 strains were analyzed from January of 2002 to December of 2005 in the Mycobacteria Sector of the Adolfo Lutz Institute, located in the city of Santos, Brazil. Samples were obtained from clinical specimens collected from patients with respiratory symptoms treated at basic health clinics in the greater metropolitan area of Santos. Ziehl-Neelsen-stained smears were prepared, 301 (40.5 percent) in MB/BacT broth and 442 (59.5 percent) on solid media, either Lowenstein-Jensen or Ogawa-Kudoh. RESULTS: The sensitivity, specificity, positive predictive value and negative predictive value obtained during the performance comparison of the two methods (cord factor detection and conventional typing) using both isolation media were, respectively, 98.5, 88, 97 and 93 percent. The method was more sensitive on solid medium (100 percent), and the difference in sensitivity between the two media types was only 2.7 percent. CONCLUSIONS: Taking into consideration the results obtained, we conclude that, in laboratories with a high incidence of M. tuberculosis complex isolation and limited economic resources, cord factor detection is a fast and valid criterion for identifying these mycobacteria using liquid or solid medium. It also enables subsequent conclusive identification tests, as well as additional sensitivity tests when necessary.

The Clinical Study of Fetal Death in Utero / 대한주산의학회잡지

OBJECTIVE: To investigate the clinical characteristics and etiologic factors of pregnancies with fetal death in utero (FDIU). METHODS: Retrospective review of medical records of 184 pregnancies with FDIU between March 1996 and March 2006 was conducted and descriptive analysis was done. Medical records were unavailable in 14 cases which were excluded in the analysis of etiology and diagnostic evaluation. RESULTS: The overall incidence was 1.31%. There was no significant difference in the yearly incidence during the study period. Age distribution of FDIU was between 18 and 44 and the incidence was highest in 25~29 year-old age group. The risk analysis showed statistically significant risk in the age group under 25 (OR, 2.455) and 25~29 (OR, 1.590) compared to 30~34 year-old age group. The risk of age group beyond 35 has a tendency to increase but was not statistically significant. FDIU was the most prevalent (38.58%) among pregnancies less than 29 weeks of gestation. Most of cases were delivered vaginally (86.5%). Etiologic factors included unexplained causes (37.1%), fetal factors (29.4%), placental and cord factors (18.2%) and maternal factors (15.3%). Autopsy was done in 128 cases (75.3%) and placental pathology was examined in 148 cases (87.1%). Among the workups done, autopsy and placental pathology were the most informative. CONCLUSION: Despite the advance of prenatal care, the incidence of FDIU was steady throughout the study period. The etiology of the largest proportion was unexplained. Once FDIU is diagnosed, prompt delivery should be done and appropriate diagnostic tests should be offered to aid in next pregnancy.

Cord formation and colony morphology for the presumptive identification of Mycobacterium tuberculosis complex

The identification of Mycobacterium tuberculosis complex (MT), using non-molecular methods, is time-consuming. The objective of this study was to evaluate a screening test for the presumptive identification of MT, which could potentially decrease laboratory turn-around time for reporting preliminary results. From January 1998 to December 1999, 3056 cultures were analysed at the Mycobacterial Laboratory, Instituto Adolfo Lutz, S los o Paulo, Brasil. The screening test consisted of observation of colony morphology on L que wenstein Jensen medium and evaluation of cord formation on smear microscopy from those positive cultures. After the screening test, the cultures identified as non-tuberculous mycobacteria were identified to species by conventional methods (growth on culture and biochemical tests). Those identified as MT were submitted to drug susceptibility tests. The presumptive identification of MT using the proposed screening test, when compared with conventional tests, presented 98.9, 86.9, 97.8 and 93.0 percent of sensitivity, specificity, positive and negative predictive values, respectively. The conclusion is that it is possible to make a presumptive identification of MT using visual analysis of colony morphology and cord formation on microscopy examination. This method could be used to report the presumptive identification of MT and to guide laboratory decisions regarding susceptibility and identification tests with little cost and in a very practical way.

Studies on lipids in mycobacterial cell wall: their important structure and function relating to pathogenicity and their biological activity.

The lipids cord-factor, mycosides and sulpholipids are supposed to be vitally linked with the pathogenecity of mycobacteria. In this paper an attempt has been made to clarify the understanding of the occurrence, organisation and possible interaction of the diverse lipids present in the mycobacterial cell wall and their possible structure and function.

Participation of tumor necrosis factor in the antitumor activity of mycobacterial trehalose dimycolate (cord factor)

Trehalose dimycolate, a mycobacterial glycolipid also known as cord factor, retains some of the antitumor properties of the intact BCG. Murine macrophages incubated in vitro in the presence of trehalose dimycolate for 20 h at 37-C released a factor which was cytotoxic for the L929 tumor cell line. Anti-tumor necrosis factor (TNF) blocked the cytotoxicity of trehalose dimycolate macrophage supernatant. Therefore the antitumor activity of trehalose dimycolate can be attributed to TNF released in the in vitro assay