ABSTRACT
Objective To compare the application of PCR-fluorescence probe, Bactec MGIT960 and Xpert MTB／RIF in diagnosis of tuberculosis from non-respiratory specimens.Methods Non-respiratory specimens from 225 patients with suspected tuberculosis admitted in Zhejiang Hospital of Integrated Chinese Medicine and Western Medicine from October 2017 to August 2018 were collected.There were 177 cases of tuberculosis and 48 cases of non-tuberculosis confirmed by clinical diagnosis.All specimens were tested with PCR-fluorescence probe, Xpert MTB／RIF and Bactec MGIT960.The clinical diagnostic results were used as the gold standard, and the receiver operating characteristic curve ( ROC) was drawn to evaluate the diagnostic values of three methods.The consistency of PCR-fluorescence probe method with Xpert MTB／RIF assay was analyzed.Results The sensitivity of PCR-fluorescent probe, Xpert MTB／RIF and Bactec MGIT960 in diagnosis of tuberculosis was 53.67%(95／177), 58.76%(104／177) and 31.07%(55／177), respectively.The sensitivity of PCR-fluorescent probe and Xpert MTB／RIF was higher than that of Bactec MGIT 960 culture ( χ2 ＝17.60 and 27.41, P＜0.01), while there was no significant difference between the PCR-fluorescent probe and the Xpert MTB／RIF (χ2 ＝0.93, P＞0.05).The specificity of three methods were 100.00%(48／48), 100.00%(48／48) and 97.92%(47／48), respectively (F＝1.83, P＞0.05).ROC curve analysis showed that the area under the ROC curve ( AUC) of PCR-fluorescent probe, Xpert MTB／RIF, and Bactec MGIT960 was 0.768, 0.794, and 0.645, respectively.The diagnostic value of PCR-fluorescent probe and Xpert MTB／RIF for tuberculosis was significantly higher than that of Bactec MGIT960 (Z＝5.19 and 6.52, P＜0.01); while Xpert MTB／RIF was superior to PCR-fluorescence probe (Z＝2.8, P＜0.05).In various types of specimens , there was no significant difference in the detection rate of tuberculosis between PCR-fluorescent probe method and Xpert MTB／RIF (χ2 ＝0.73, P＞0.05).The PCR-fluorescent probe and Xpert MTB／RIF had a good consistency (kappa＝0.829).Conclusion Xpert MTB／RIF is superior to PCR-fluorescence probe in the detection of tuberculosis in non-respiratory specimens such as tissues and pus, but the two have good consistency.The PCR-fluorescence probe method is economical and practical , and easy to promote, which has a high clinical application prospects.
ABSTRACT
O diagnóstico rápido da tuberculose (TB) é fundamental para a redução da taxa detransmissão da doença e conseqüentemente do número de pessoas infectadas peloindivíduo doente além de possibilitar a prevenção do óbito e as seqüelas causadaspela progressão da doença sem tratamento. A baciloscopia possui baixasensibilidade e o maior problema da cultura para micobactérias é o longo tempo de incubação necessário, até oito semanas. Novos testes, apesar do custo elevado, podem representar um avanço no combate à doença. O teste AmplifiedMycobacterium tuberculosis Direct (MTD; Gen-Probe; San Diego, CA) é capaz dedetectar o rRNA do complexo M. tuberculosis em aproximadamente 3 horas, porémé necessário um melhor entendimento da performance deste teste para clientelapaucibacilar, que é o caso de pacientes HIV positivo, já que a qualidade de suasamostras normalmente dificulta o diagnóstico laboratorial tanto pela baciloscopiaquanto pela cultura. Este estudo foi realizado no Laboratório de Bacteriologia eBioensaios do Instituto de Pesquisa Clínica Evandro Chagas da Fundação OswaldoCruz e tem como objetivo comparar o teste Amplified Mycobacterium tuberculosisDirect com métodos de referência para o diagnóstico laboratorial de tuberculose empacientes HIV positivo na forma de um estudo retrospectivo de acurácia diagnósticacomparando os resultados do MTD com cultura em LJ e BACTEC MGIT 960. Foramanalisadas amostras respiratórias de 118 pacientes, 74,4% do sexo masculino, eidade média de 36,61 ± 10,6 anos. O MTD identificou 31% das amostras comocomplexo M. tuberculosis (M.tb). Entre as culturas em BACTEC MGIT 960, 29,7 por centoforam isolados como M.tb e as culturas em LJ isolaram 27,1%...
Rapid diagnosis of tuberculosis (TB) is important to reduce the rate of diseasetransmission and the number of infected people, enabling prevention of death andsequel caused by disease progression without treatment. The bacilloscopy has lowsensitivity and mycobacteria culture takes long incubation time, up to eight weeks.New tests, despite the high cost, may represent a breakthrough in combating thedisease. The Amplified Mycobacterium tuberculosis Direct Test (MTD, Gen-Probe,San Diego, CA) is capable of detecting the rRNA of the M. tuberculosis in about 3hours, but a better understanding of the performance of this test in paucibacillaryclientele is needed, which is the case of HIV positive patients, since the quality oftheir samples usually difficult both for the laboratory diagnosis by smear and culture.This study was conducted at the Laboratory of Bacteriology and bioassays of theClinical Research Institute Evandro Chagas, Oswaldo Cruz Foundation, and aims tocompare the Amplified Mycobacterium tuberculosis Direct Test with referencemethods for the laboratory diagnosis of tuberculosis in HIV positive patients with aretrospective study of diagnostic accuracy by comparing the results of MTD with LJand BACTEC MGIT 960. We analyzed respiratory samples from 118 patients, 74.4%, mean age 36.61 ± 10.6 years...
Subject(s)
AIDS-Related Opportunistic Infections , Nucleic Acids , Tuberculosis/diagnosis , Tuberculosis/epidemiology , Polymerase Chain ReactionABSTRACT
BACKGROUND: PCR is a widely used method for rapid and accurate diagnosis of mycobacteriosis. The sensitivity and specificity of a real time PCR kit newly developed in Korea were evaluated for detecting mycobacteria in respiratory specimens. METHODS: One hundred twenty nine Mycobacterium tuberculosis (TB) culture positive respiratory specimens (82 AFB stain positive and 47 stain negative specimens) were used for evaluation of the sensitivity. Nine non-tuberculous mycobacteria (NTM) culture positive specimens were also included. For evaluation of the specificity, 48 AFB stain and culture negative respiratory specimens from patients who were initially not fully excluded from mycobacterial diseases (specificity group 1) were used. Other 51 respiratory specimens from patients who were not suspected of mycobacterial diseases were also included (specificity group 2). Real time PCR was performed by using AdvanSure TB/NTM real time PCR Kit (LG Lifescience, Korea) and SLAN real time PCR detection system (LG Lifescience). The target genes of TB and NTM were IS6110 and rpoB, respectively. RESULTS: Among 129 TB culture positive specimens, 82 of 82 AFB stain positive specimens (100%) and 35 of 47 (74.5%) stain negative specimens revealed real time PCR positivity for TB, resulting in sensitivity of 90.7%. Five of nine NTM culture positive specimens resulted in real time PCR positivity for NTM (55.6%). Forty seven of 48 specimens (97.9%) and all 51 specimens (100%) of the specificity group 1 and 2, respectively, were real time PCR negative for TB and NTM. CONCLUSIONS: AdvanSure TB/NTM real time PCR Kit should be useful for detecting TB in respiratory specimens with high sensitivity and specificity.