Comparison of different diagnostic modalities for isolation of Mycobacterium Tuberculosis among suspected tuberculous lymphadenitis patients / Comparação de diferentes modalidades de diagnóstico para isolamento de Mycobacterium tuberculosis entre pacientes com suspeita de linfadenite tuberculosa

Tuberculosis is a communicable disease with high morbidity and mortality rates in developing countries. The study's primary objective is to compare conventional methods such as acid-fast bacillus (AFB) culture and microscopy with rapid diagnostic methods. The secondary objective is to compare histopathological and microbiological findings in suspected patients with tubercular lymphadenitis. A total of 111 samples (August 2018 to September 2019) of lymph nodes were processed for AFB microscopy, AFB cultures, drug-susceptibility testing (DST), histopathology, and Xpert Mycobacterium Tuberculosis (MTB)/resistance to Rifampin (RIF) assays. Out of 111 lymph node samples, 6 (5.4%) were positive for AFB smear microscopy, 84 (75.6%) were positive for AFB culture, 80 (70.7%) were positive on Gene Xpert, and 102 (91.8%) were indicative of tuberculosis for histopathology studies. Mycobacteria growth indicator tube (MGIT) culture positivity was 84 (75.6%) higher than solid Lowenstein-Jensen (LJ) culture 74 (66.6%). Positive cultures underwent phenotypic DST. Two cases were Multidrug-resistant (MDR) on DST, while three cases were Rifampicin resistant on Gene Xpert. The sensitivity of Genexpert was (62%) against the conventional AFB culture method. The poor performance of conventional lymphadenitis diagnostic methods requires early and accurate diagnostic methodology. Xpert MTB/RIF test can help in the treatment of multidrug-resistant TB cases. Nonetheless, rapid and conventional methods should be used for complete isolation of Mycobacterium tuberculosis.

A tuberculose é uma doença transmissível com altas taxas de morbimortalidade nos países em desenvolvimento. O objetivo principal do estudo é comparar métodos convencionais, como cultura de bacilo álcool-ácido resistente (BAAR) e microscopia, com métodos de diagnóstico rápido. O objetivo secundário é comparar os achados histopatológicos e microbiológicos em pacientes com suspeita de linfadenite tubercular. Um total de 111 amostras (agosto de 2018 a setembro de 2019) de gânglios linfáticos foi processado para microscopia de AFB, culturas de AFB, teste de susceptibilidade a drogas (DST), histopatologia e Xpert Mycobacterium tuberculosis (MTB)/ensaios de resistência à rifampicina (RIF). Das 111 amostras de linfonodos, 6 (5,4%) foram positivas para baciloscopia de AFB, 84 (75,6%) foram positivas para cultura de AFB, 80 (70,7%) foram positivas para o GeneXpert e 102 (91,8%) foram indicativas de tuberculose para estudos histopatológicos. A positividade da cultura do tubo indicador de crescimento de micobactérias (MGIT) foi 84 (75,6%), maior que a cultura sólida de Lowenstein-Jensen (LJ), 74 (66,6%). As culturas positivas foram submetidas a DST fenotípico. Dois casos eram multirresistentes (MDR) ao DST, enquanto três casos eram resistentes à rifampicina no GeneXpert. A sensibilidade do GeneXpert foi 62% contra o método convencional de cultura AFB. O fraco desempenho dos métodos convencionais de diagnóstico de linfadenite requer metodologia de diagnóstico precoce e precisa. O teste Xpert MTB/RIF pode ajudar no tratamento de casos de tuberculose multirresistente. No entanto, métodos rápidos e convencionais devem ser usados para o isolamento completo do Mycobacterium tuberculosis.

Comparison of different diagnostic modalities for isolation of Mycobacterium Tuberculosis among suspected tuberculous lymphadenitis patients / Comparação de diferentes modalidades de diagnóstico para isolamento de Mycobacterium tuberculosis entre pacientes com suspeita de linfadenite tuberculosa

Tuberculosis is a communicable disease with high morbidity and mortality rates in developing countries. The study's primary objective is to compare conventional methods such as acid-fast bacillus (AFB) culture and microscopy with rapid diagnostic methods. The secondary objective is to compare histopathological and microbiological findings in suspected patients with tubercular lymphadenitis. A total of 111 samples (August 2018 to September 2019) of lymph nodes were processed for AFB microscopy, AFB cultures, drug-susceptibility testing (DST), histopathology, and Xpert Mycobacterium Tuberculosis (MTB)/resistance to Rifampin (RIF) assays. Out of 111 lymph node samples, 6 (5.4%) were positive for AFB smear microscopy, 84 (75.6%) were positive for AFB culture, 80 (70.7%) were positive on Gene Xpert, and 102 (91.8%) were indicative of tuberculosis for histopathology studies. Mycobacteria growth indicator tube (MGIT) culture positivity was 84 (75.6%) higher than solid Lowenstein-Jensen (LJ) culture 74 (66.6%). Positive cultures underwent phenotypic DST. Two cases were Multidrug-resistant (MDR) on DST, while three cases were Rifampicin resistant on Gene Xpert. The sensitivity of Genexpert was (62%) against the conventional AFB culture method. The poor performance of conventional lymphadenitis diagnostic methods requires early and accurate diagnostic methodology. Xpert MTB/RIF test can help in the treatment of multidrug-resistant TB cases. Nonetheless, rapid and conventional methods should be used for complete isolation of Mycobacterium tuberculosis.(AU)

A tuberculose é uma doença transmissível com altas taxas de morbimortalidade nos países em desenvolvimento. O objetivo principal do estudo é comparar métodos convencionais, como cultura de bacilo álcool-ácido resistente (BAAR) e microscopia, com métodos de diagnóstico rápido. O objetivo secundário é comparar os achados histopatológicos e microbiológicos em pacientes com suspeita de linfadenite tubercular. Um total de 111 amostras (agosto de 2018 a setembro de 2019) de gânglios linfáticos foi processado para microscopia de AFB, culturas de AFB, teste de susceptibilidade a drogas (DST), histopatologia e Xpert Mycobacterium tuberculosis (MTB)/ensaios de resistência à rifampicina (RIF). Das 111 amostras de linfonodos, 6 (5,4%) foram positivas para baciloscopia de AFB, 84 (75,6%) foram positivas para cultura de AFB, 80 (70,7%) foram positivas para o GeneXpert e 102 (91,8%) foram indicativas de tuberculose para estudos histopatológicos. A positividade da cultura do tubo indicador de crescimento de micobactérias (MGIT) foi 84 (75,6%), maior que a cultura sólida de Lowenstein-Jensen (LJ), 74 (66,6%). As culturas positivas foram submetidas a DST fenotípico. Dois casos eram multirresistentes (MDR) ao DST, enquanto três casos eram resistentes à rifampicina no GeneXpert. A sensibilidade do GeneXpert foi 62% contra o método convencional de cultura AFB. O fraco desempenho dos métodos convencionais de diagnóstico de linfadenite requer metodologia de diagnóstico precoce e precisa. O teste Xpert MTB/RIF pode ajudar no tratamento de casos de tuberculose multirresistente. No entanto, métodos rápidos e convencionais devem ser usados para o isolamento completo do Mycobacterium tuberculosis.(AU)

De la escrófula a la linfoadenitis micobacteriana / From scrophula to mycobacterial lymphadenitis

Resumen En el siglo XIX se pensaba que la tuberculosis y la tumefacción ganglionar cervical llamada escrófula afectaban a individuos predispuestos por una "constitución diatésica" heredada. En 1882 Robert Koch demostró que lesiones tuberculosas y escrofulosas humanas eran causadas por el bacilo Mycobacterium tuberculosis. A principios del siglo XX se estableció que Mycobacterium bovis, bacilo de la tuberculosis del ganado, podía también causar linfoadenitis cervical en humanos, especialmente en niños, por la ingestión de leche de vacas enfermas. La condición disminuyó después que se controló la infección en el ganado y se introdujo la pasteurización de la leche. En 1956 se describió la linfoadenitis cervicofacial granulomatosa necrosante y supurada causada por micobacterias no tuberculosas. Afecta principalmente a niños bajo los cinco años, especialmente en países sin endemia de tuberculosis. Las linfoadenitis cervicales tuberculosas predominan en adultos jóvenes en países con tuberculosis endémica y en individuos infectados por VIH.

In the 19th century it was widely believed that both tuberculosis and cervical lymph node swelling, known as scrophula, affected individuals predisposed to an inherited "diathetic constitution". In 1882 Robert Koch proved that human tuberculosis and scrophulous lesions were caused by the bacillus Mycobacterium tuberculosis. In the early twentieth century it was stated that Mycobacterium bovis, the bacillus of cattle tuberculosis, could also cause cervical lymphoadenitis in humans, especially in children, by the intake of milk from sick cows. The incidence of this condition decreased after the infection was controlled in cattle and pasteurization of the milk was introduced. A type of granulomatous necrotizing and suppurative cervico-facial lymphadenitis associated to non-tuberculous mycobacteria was described in 1956. It mainly affects children younger than 5 years old, particularly those born in countries with non-endemic tuberculosis. Tuberculous cervical lymphadenitis is prevalent in young adults from tuberculosis-endemic countries and in HIV-infected subjects. Infectious etiology displaced the importance of a personal disposition in the development of scrophula. Nevertheless, mutations that confer susceptibility to mycobacterial infection are currently investigated.

[From scrophula to mycobacterial lymphadenitis]. / De la escrófula a la linfoadenitis micobacteriana.

In the 19th century it was widely believed that both tuberculosis and cervical lymph node swelling, known as scrophula, affected individuals predisposed to an inherited "diathetic constitution". In 1882 Robert Koch proved that human tuberculosis and scrophulous lesions were caused by the bacillus Mycobacterium tuberculosis. In the early twentieth century it was stated that Mycobacterium bovis, the bacillus of cattle tuberculosis, could also cause cervical lymphoadenitis in humans, especially in children, by the intake of milk from sick cows. The incidence of this condition decreased after the infection was controlled in cattle and pasteurization of the milk was introduced. A type of granulomatous necrotizing and suppurative cervico-facial lymphadenitis associated to non-tuberculous mycobacteria was described in 1956. It mainly affects children younger than 5 years old, particularly those born in countries with non-endemic tuberculosis. Tuberculous cervical lymphadenitis is prevalent in young adults from tuberculosis-endemic countries and in HIV-infected subjects. Infectious etiology displaced the importance of a personal disposition in the development of scrophula. Nevertheless, mutations that confer susceptibility to mycobacterial infection are currently investigated.

Xpert MTB/RIF for diagnosis of tuberculous cervical lymphadenitis in HIV-infected patients.

OBJECTIVES/HYPOTHESIS: The World Health Organization endorsed the Xpert MTB/RIF assay for the diagnosis of pulmonary tuberculosis (TB), but there is limited information about the utility of this assay for the diagnosis of TB lymphadenitis. Therefore, the objective of this study was to assess the diagnostic accuracy of Xpert MTB/RIF assay in HIV-infected patients with palpable cervical lymph nodes. STUDY DESIGN: Prospective, diagnostic test study. METHODS: Consecutive patients with cervical lymphadenopathy were prospectively enrolled between January 2011 and March 2013. Lymph node specimens were obtained through fine-needle aspiration or excisional biopsy. Mycobacterial culture was considered as the gold standard. RESULTS: Mycobacterium TB was cultured from 15 of 68 specimens (22.05%), and 53 specimens had negative cultures (77.94%). The sensitivity of Xpert MTB/RIF was 100% (95% CI, 74.65%-100%), and the specificity was 100% (95% CI, 91.58%-100%). Smear microscopy had a lower diagnostic performance. CONCLUSION: Although based on a limited sample size, our study indicates that Xpert MTB/RIF is a useful method for the diagnosis of cervical TB lymphadenitis in HIV-infected patients, regardless of the bacillary load in smear-positive samples or the CD4 T cell count. The sensitivity, specificity, positive predictive value, and negative predictive value were similar to gold-standard culture. LEVEL OF EVIDENCE: N/A.

Mycobacterium tuberculosis complex detected by modified fluorescent in situ hybridization in lymph nodes of clinical samples.

INTRODUCTION: Lymph node tuberculosis (TB) is the leading cause of extrapulmonary tuberculosis and is the most frequently identified type in Aguascalientes, Mexico. Conventional diagnosis has serious limitations for rapid detection of extrapulmonary tuberculosis in clinical samples. Here PCR and modified FISH have been tested as complementary diagnosis methods for extrapulmonary tuberculosis. METHODOLOGY: The specific insertion sequence IS6110 for Mycobacterium tuberculosis complex was used to perform PCR and build DNA and PNA FISH probes (20bp). PCR and modified DNA and PNA FISH assays were performed to evaluate 41 lymph node paraffin-embedded tissue samples, in comparison with the histopathology diagnosis, which was considered the gold standard (22 positive and 19 negative). RESULTS: In comparison with histopathology diagnosis PCR showed 62.5 % sensitivity and 77.8 % specificity (χ(2) = 4.583 p < 0.05). Modified DNA FISH showed 71.4% sensitivity and 84.6% specificity (χ(2) = 11.21 p < 0.05). PNA FISH showed 66.7% sensitivity and 60.0% specificity (χ(2) = 2.93 p > 0.05). Ziehl Neelsen stain was positive in only four cases of 22 lymph node samples positive to histopathology.  In contrast, PCR and modified DNA FISH were positive in 20 cases of the same group. The negative cases were coincident in all tests. CONCLUSIONS: PCR and DNA FISH showed a significant increase in the number of cases detected and also showed higher sensitivity and specificity compared with data reported by traditional methodology. In developing countries, these techniques could help to complement the early diagnosis and timely treatment of extrapulmonary tuberculosis.

HIV-associated tuberculous lymphadenitis: the importance of polymerase chain reaction (PCR) as a complementary tool for the diagnosis of tuberculosis - a study of 104 patients.

BACKGROUND: Lymphadenitis is common in HIV-positive patients. Diagnosis of the infections associated with this condition is complex, particularly in the case of tuberculosis. Rapid and specific detection of Mycobacterium tuberculosis (M. tuberculosis) is fundamental in ensuring adequate treatment. In addition, frequent causes of lymphadenitis such as those associated with lymphoma and histoplasmosis, among others, must be eliminated as possible causes. OBJECTIVES: To evaluate the accuracy of polymerase chain reaction as a tool for the diagnosis of lymphadenitis resulting from M. tuberculosis. METHODS: In this study, a protocol was developed using the following procedures: direct microscopy using Ziehl-Neelsen staining, culture in Lowenstein-Jensen medium, histology and polymerase chain reaction. RESULTS: A total of 104 patients were included in the study. According to histopathology, 38 patients (36%) were found to have nonspecific chronic lymphadenitis, 27 (26%) had tuberculous lymphadenitis, 11 patients (10.5%) had lymphoma and 9 (8.7%) had histoplasmosis. When Lowenstein-Jensen culture was performed, positive tests for tuberculous lymphadenitis increased by 30%. With polymerase chain reaction, M. tuberculosis DNA was detected in 6 out of 38 samples of non-specific chronic lymphadenitis. Three of these patients were followed up, developed symptoms of tuberculosis and were cured following specific treatment. CONCLUSION: The data obtained in this study suggest that all cases of lymphadenopathies should be submitted to histopathology, Lowenstein-Jensen or Ogawa culture and polymerase chain reaction. Polymerase chain reaction may prove to be useful in providing an early and accurate detection of cases of extrapulmonary tuberculosis in HIV-positive patients with lymphadenopathies, avoiding empirical treatment and the possible development of resistant strains.

HIV-associated tuberculous lymphadenitis: the importance of polymerase chain reaction (PCR) as a complementary tool for the diagnosis of tuberculosis - a study of 104 patients / Linfadenite tuberculosa associada ao HIV: a importância da reação em cadeia de polimerase (PCR) como ferramenta complementar para o diagnóstico da tuberculose - estudo de 104 pacientes

BACKGROUND: Lymphadenitis is common in HIV-positive patients. Diagnosis of the infections associated with this condition is complex, particularly in the case of tuberculosis. Rapid and specific detection of Mycobacterium tuberculosis (M. tuberculosis) is fundamental in ensuring adequate treatment. In addition, frequent causes of lymphadenitis such as those associated with lymphoma and histoplasmosis, among others, must be eliminated as possible causes. OBJECTIVES: To evaluate the accuracy of polymerase chain reaction as a tool for the diagnosis of lymphadenitis resulting from M. tuberculosis. METHODS: In this study, a protocol was developed using the following procedures: direct microscopy using Ziehl-Neelsen staining, culture in Lowenstein-Jensen medium, histology and polymerase chain reaction. RESULTS: A total of 104 patients were included in the study. According to histopathology, 38 patients (36 percent) were found to have nonspecific chronic lymphadenitis, 27 (26 percent) had tuberculous lymphadenitis, 11 patients (10.5 percent) had lymphoma and 9 (8.7 percent) had histoplasmosis. When Lowenstein-Jensen culture was performed, positive tests for tuberculous lymphadenitis increased by 30 percent. With polymerase chain reaction, M. tuberculosis DNA was detected in 6 out of 38 samples of non-specific chronic lymphadenitis. Three of these patients were followed up, developed symptoms of tuberculosis and were cured following specific treatment. CONCLUSION: The data obtained in this study suggest that all cases of lymphadenopathies should be submitted to histopathology, Lowenstein-Jensen or Ogawa culture and polymerase chain reaction. Polymerase chain reaction may prove to be useful in providing an early and accurate detection of cases of extrapulmonary tuberculosis in HIV-positive patients with lymphadenopathies, avoiding empirical treatment and the possible development of resistant strains.

FUNDAMENTOS: A linfadenite é comum em pacientes HIV-positivos. O diagnóstico das infecções associadas a essa condição é complexo, especialmente em relação à tuberculose. A detecção rápida e específica do Mycobacterium tuberculosis (M. tuberculosis) é essencial para o tratamento adequado. Além disso, frequentes causas de linfadenites tais como as relacionadas a linfoma, histoplasmose, e outras, devem ser afastadas. OBJETIVOS: Avaliar a importância da biópsia cirúrgica excisional das linfadenites e realização dos exames histopatológicos, exames baciloscópicos (Ziehl-Neelsen), cultura (Lowenstein-Jensen) e reação em cadeia da polimerase (PCR) com finalidade diagnostica MÉTODOS: Desenvolveu-se um protocolo para biópsias excisionais de linfonodos, adotando-se os seguintes procedimentos: exame direto de esfregaços corados pelo método de Ziehl-Neelsen, cultura em meio de Lowenstein-Jensen, exame anátomo-patológico e PCR. RESULTADOS: Ao todo foram incluídos 104 pacientes, e o exame histopatológico evidenciou 36 por cento (n = 38 pacientes) de casos de linfadenite crônica inespecífica, 26 por cento (n = 27) de linfadenite tuberculosa, 10,5 por cento (n =11) de linfoma e 8,7 por cento (n = 9) de histoplasmose. Através da cultura no meio de Lowenstein-Jensen, os casos positivos para linfadenite tuberculosa aumentaram para 30 por cento. A PCR detectou M. tuberculosis em 6 das 38 amostras de linfadenite crônica inespecífica. Três desses pacientes foram acompanhados, exibiram sintomas de tuberculose e foram curados após tratamento específico. CONCLUSÃO: Os dados obtidos neste trabalho sugerem que em todos os casos de linfadenopatia deve-se realizar exame histopatológico, cultura em Lowenstein-Jensen ou Ogawa e reação em cadeia da polimerase. A reação em cadeia da polimerase pode ser útil na detecção precoce e acurada de casos de TB extrapulmonar nos pacientes HIV-positivos com linfadenopatias, evitando-se o uso de tratamentos empíricos e o eventual desenvolvimento de cepas resistentes.

Biopsy of peripheral lymph nodes: a useful tool to diagnose opportunistic diseases in HIV-infected patients.

Peripheral lymphadenopathy is commonly present in HIV-infected patients and has a wide spectrum of differential diagnoses. We carried out a cross-sectional study of peripheral lymph node biopsies performed from January 2004 to December 2008 in HIV-infected patients who attended a tertiary-care hospital in southern Brazil. Only 60 of 210 peripheral lymph node biopsies performed (28%) were non-diagnostic. The most common diagnoses included: mycobacteriosis (105 cases; 50.2%); lymphoma (19 cases; 9.0%); systemic mycosis (12 cases; 5.7%) including histoplasmosis, cryptococcosis and histoplasmosis; and metastatic cancer (2.9%). Peripheral lymph node biopsy is a simple and useful tool to diagnose opportunistic diseases in HIV-infected patients.

Clinical evaluation of a 16S ribosomal RNA polymerase chain reaction test for the diagnosis of lymph node tuberculosis.

UNLABELLED: Reports on the sensitivity of polymerase chain reaction (PCR) for the diagnosis of lymph node tuberculosis (TB) show divergent results. We evaluated the accuracy of the Roche Amplicor Mycobacterium tuberculosis PCR test with lymph node aspirate and biopsy samples. METHODS: The study was conducted at a public reference hospital in Lima, Peru. From the period of January 2003 to January 2004, we included patients who had lymphadenopathy and in whom the attending physician suspected TB. Aspirate and biopsy samples were submitted for culturing in Lowenstein-Jensen medium, for histopathologic testing, and for PCR. The sensitivity and specificity of PCR were calculated against a reference standard based on histopathologic findings and culture. RESULTS: Our study included 154 patients. Median age was 29 years (interquartile range, 21-40 years); 97 patients (62.9%) were men. Twenty-nine patients (18.8%) had acid fast bacilli-positive histopathologic findings, and 44 (28.6%) had a positive culture result. Using the combination of histopathologic findings and culture as reference standard, 55 patients (35.7%) had a diagnosis of tuberculous lymphadenitis. The sensitivity of the PCR test was 58.2%, and the specificity was 93.9%. For biopsy tissue only, the sensitivity of PCR was 52.7%, and the specificity was 97.0%. For aspirate samples only, the sensitivity of PCR was 47.3%, and the specificity was 96.0%. CONCLUSION: The Amplicor PCR test revealed low sensitivity and high specificity for the diagnosis of lymph node TB. The sensitivity was higher in cases in which the bacillary load was high--in acid fast bacilli-positive samples and among HIV-infected patients. Considering the results of microbiological and PCR tests together, there was still a patient group in whom no final diagnosis could be established.

Mycobacterium bovis versus Mycobacterium tuberculosis as a cause of acute cervical lymphadenitis without pulmonary disease.

Bovine tuberculosis remains a common disease of cattle in countries such as Mexico. Children eating unpasteurized dairy products from Mexican cattle can develop Mycobacterium bovis cervical lymphadenitis. However, the bovine mycobacterium can be misdiagnosed as Mycobacterium tuberculosis based on standard laboratory testing. Accurate speciation is important for selection of the preferred antibiotic regimen for treatment of Mycobacterium bovis infection.

[Tuberculosis lymphadenitis in slaughtered swine from the State of São Paulo, Brazil: microscopic histopathology and demonstration of mycobacteria]. / Linfadenites tuberculóides em suínos abatidos no estado de São Paulo, Brasil: aspectos macroscópicos histopatológicos e pesquisa de micobactérias.

INTRODUCTION: As the occurrence of tuberculosis lymphadenitis in swine constitutes a public health risk, especially in immunosuppressed individuals, the distribution of tuberculoid lesions and the presence of microbacteria in lymph nodes and hepatic and muscular tissue in swine for slaughter, in the State of S. Paulo, SP (Brazil), in the period from 1993 to 1994, were studied. MATERIAL E METHOD: Tuberculous lesions in 60 carcasses of swine, slaughtered at abattoirs during the period 1993-1994, were studied. When macroscopic lesions were observed, a representative sampling of lymph nodes, hepatic and muscular tissues (masseter and diaphragm) were examined using histopathological and microbacterial isolation techniques. RESULTS: The macroscopic lesions were found predominantly in mesenteric lymph nodes. The MAI Complex (M.avium-intracellulare) was isolated mainly in the carcass group that showed lesions and was not found in the control group. Microorganisms of the MAI Complex were not isolated from hepatic and muscular tissues. CONCLUSION: No clear relationship between the type of mycobacteria isolated and the macroscopic lesions observed during the carcass inspection was found.

[Cervical granulomatous lymphadenitis: report of 13 cases]. / Linfadenitis granulomatosa cervical. A propósito de 13 casos.

The most common manifestation of mycobacterial infection encountered in E.N.T. practice is cervical lymphadenitis. Mycobacterial cervical lymphadenitis, the so-called scrofula, remains a diagnostic challenge, because it mimics other resembling processes. We present 13 cases of cervical granulomatous lymphadenitis treated from 1967 until 1990.