Detection of M. tuberculosis in clinical samples of diversified nature by IS6110 based PCR

Performance of the polymerase chain reaction technique based on IS6110 sequence was evaluated in clinical samples obtained from pulmonary and extrapulmonary cases of tuberculosis. One hundred and seventy two samples were processed for detection of M. tuberculosis by ZN stained smear examination, LJ medium culture, BACTEC radiometric culture and PCR tests amplifying 123bp region of IS6110 sequence. A significant difference was seen in the sensitivities of different tests, the figures being 83% for PCR test, 35.2% for smear examination, 47.16% for LJ culture and 53.45% for BACTEC culture (p < 0.05). However, no significant difference was found as far as specificity was concerned. PCR test sensitivity in. pulmonary and extrapulmonary clinical samples were 90.14% and 77.27% respectively and found to be significantly higher (p < 0.05) when compared with those of other tests. The mean detection time for M. tuberculosis was 24.03 days by LJ medium culture, 12.89 days by BACTEC culture and less than one day by PCR test. PCR based on IS6100 sequence is highly sensitive method for the early diagnosis of pulmonary and extrapulmonary tuberculosis.     

Is it appropriate to routinely use a nucleic acid amplification test for the diagnosis of tuberculosis?

The purpose of this study was to compare the usefulness of the nucleic acid amplification (NAA) test against conventional tests under normal laboratory operational conditions. The NAA test was performed on the first sputum specimen of all patients. Liquid media culture, solid media culture, and Ziehl-Neelsen stain for an acid-fast bacilli (AFB) smear were performed on three sputum specimens. The results were calculated using the gold standard of either the culture results or the clinical diagnosis. Of the 593 patients tested, 151 (25.5%) were diagnosed with pulmonary tuberculosis. The sensitivity of the first specimen only was 64% for the NAA test, 54% for the AFB smear, 77% for BACTEC MGIT 960 culture, 40% for Lowestain-Jensen (LJ) culture, and 25% for 7H11 culture. The sensitivity when using all three specimens increased to 63% for AFB smear, 87% for BACTEC MGIT 960 culture, 51% for LJ culture, and 40% for 7H11 culture. The specificity was 100% for all culture tests, 99% for the AFB smear, and 99.5% for NAA test. The mean turnaround time was 1.34 days for NAA, 0.59 days for AFB smear, 11 days for BACTEC MGIT 960 culture, 23 days for LJ culture, and 20 days for 7H11 culture. We conclude that the sensitivity of NAA is still far from ideal, and the test is not cost effective. Thus, the COBAS AMPLICOR PCR system is not suitable for routine use in microbiology laboratories.     

Polymerase chain reaction of pleural biopsy is a rapid and sensitive method for the diagnosis of tuberculous pleural effusion

BACKGROUND: Tuberculous pleural effusion occurs in 30% of patients with tuberculosis (TB). Rapid diagnosis of a tuberculous pleural effusion would greatly facilitate the management of many patients. Polymerase chain reaction (PCR) has been used to detect Mycobacterium tuberculosis in pleural fluid with highly variable sensitivity. OBJECTIVE: To improve our laboratory diagnosis of tuberculous pleural effusion. METHODS: We applied PCR to detect DNA specific for M tuberculosis in 33 of the studied pleural biopsy specimens using an IS986-based primer that was specific for mycobacterium complex, and compared it to the results of pleural fluid and biopsy cultures performed on either Lowenstein-Jensen (LJ) medium or BACTEC 12B liquid medium (Becton Dickinson Microbiology Systems; Cockeysville, MD), Ziehl-Neelsen (ZN) staining, and histopathology in 45 patients with pleural effusion. RESULTS: Of the 45 patients with pleural effusion who were studied, 26 patients received diagnoses of tuberculous pleural effusion that had been confirmed by either culture and or histopathology, 10 patients received diagnoses of exudative effusion due to causes other than TB, and 9 patients received diagnoses of transudative effusion. Histopathology of the pleural biopsy specimen had a sensitivity of 53.8%. The sensitivity of the ZN staining of pleural fluid and biopsy specimens was 0.0% and 3.8%, respectively. The sensitivity of the culture on both BACTEC 12B liquid medium and LJ medium was higher in pleural biopsy specimens (92.3%) than in pleural fluid specimens (15.4%; p > 0.001). The improvements of the BACTEC culture system improved and shortened the detection time of M tuberculosis in pleural biopsy specimens. PCR of pleural biopsy specimens had 90% sensitivity and 100% specificity. The positive predictive value and the negative predictive value for pleural biopsy specimen cultures were 100% and 90.5% vs 100% and 86.7% for pleural biopsy specimen PCRs. CONCLUSION: The overall accuracy of PCR of pleural biopsy was similar to the results of pleural biopsy culture, however, PCR of the pleural biopsy was much faster in reaching diagnosis. PCR of pleural biopsy is a useful method when used in combination with the BACTEC culture system and histopathologic examination of pleural biopsy to reach a rapid diagnosis of tuberculous pleural effusion.     

Rapid detection of Mycobacterium tuberculosis from sputum specimens using the FASTPlaqueTB test.

OBJECTIVES: To determine the performance of the FASTPlaqueTB test, based on bacteriophage amplification technology, by comparison with the BACTEC 460 TB culture system, the L?wenstein-Jensen (LJ) medium culture method and Ziehl-Neelsen (ZN) staining. METHODS: Of 400 sputum specimens studied in our laboratory, 19 were excluded due to contaminant growth. The FASTPlaqueTB test was performed according to the manufacturer's instructions. RESULTS: Only 42 of the 381 specimens examined were positive on at least one test: 30 were positive with ZN staining, 34 with LJ medium, 36 with the FASTPlaqueTB test and 39 with BACTEC 460 TB. The combination of BACTEC 460 TB and LJ medium culture was considered the gold standard. The sensitivity and specificity were 70.7% and 99.7% for ZN staining, 87.8% and 100% for the FASTPlaqueTB test, 82.9% and 100% for LJ, and 95.1% and 100% for BACTEC 460 TB. CONCLUSIONS: The FASTPlaqueTB test is useful in the rapid diagnosis of TB.     

Integration of microscopy and serodiagnostic tests to screen for active tuberculosis.

SETTING: University of California San Diego Medical Center, USA. OBJECTIVE: To create a simple screening strategy for tuberculosis (TB) that includes antibody detection assays to improve the accuracy of microscopic examination of sputum for acid-fast bacilli (AFB smear). METHODS: Serum samples were obtained from 190 patients suspected of having active TB. TB diagnosis was established by Mycobacterium tuberculosis culture. HIV status was determined by commercial serologic tests. IgG antibody levels were measured by ELISA using purified M. tuberculosis antigens. Data from 130 randomly selected patients were used to develop a screening strategy; data from the remaining 60 patients were used for validation. RESULTS: AFB smear had 70% sensitivity and 88% specificity. In algorithms integrating single or multi-antigen ELISA with AFB smear and HIV results, the sensitivity improved over each test alone. The algorithm that included a four-antigen ELISA (38 kDa antigen, lipoarabinomannan, MPT-64 and glutamine synthase) had a sensitivity of 93% and a specificity of 76%. Compared to AFB smear, the sensitivity of the algorithm was significantly higher, while the specificity was not statistically different. CONCLUSION: This study demonstrates that a screening strategy can be created by integrating multi-antigen ELISA with AFB smear and HIV testing.     

Comparative performance of PCR-based assay versus microscopy and culture for the direct detection of Mycobacterium tuberculosis in clinical respiratory specimens in Lebanon.

SETTING: American University of Beirut Medical Center, Lebanon. OBJECTIVE: To assess the performance of a polymerase chain reaction (PCR) using primers that flank 542 bp within IS6110 in Mycobacterium tuberculosis (TB) vs. microscopy and BACTEC culture, in the diagnosis of tuberculosis. DESIGN: A total of 82 clinical respiratory pulmonary specimens and 73 samples from BACTEC vials were tested by the three methods. RESULTS: Of 24 smear-positive culture-positive (SP-CP) and 11 smear-negative culture-positive (SN-CP) TB specimens, PCR detected 83% and 64%, respectively. Among 17 specimens yielding mycobacteria other than tuberculosis (MOTT), the PCR was positive in 33% SP-CP and 14% SN-CP specimens. Among the 73 BACTEC vials, PCR was positive in 36 of 38 (95%) yielding culture-positive TB, and in one of 20 (5%) yielding culture positive MOTT. None of the 30 smear-negative culture-negative (SN-CN) clinical specimens and 15 of the CN vials were positive by PCR. The overall sensitivity of PCR was 77% and 95% for TB detection in respiratory specimens and BACTEC vials, respectively, and the specificity was 94% in both. CONCLUSIONS: Because a substantial number of TB cases are missed, especially in SN-CP specimens, a PCR-based assay utilizing these primers cannot be used reliably, alone, in clinical laboratory diagnosis of mycobacterial respiratory infections.     

5种方法联合检测力阴肺结核诊断价值的研究

目的 探讨痰聚合酶链反应（ＰＣＲ）ＴＢ－ＤＮＡ检测、血清结核分支杆菌糖脂免疫球蛋白Ｇ（ＬＡＭＩｇＧ）、卡介菌免疫球蛋白Ｇ（ＰＰＤＩｇＧ）、结核特异性循环免疫复合物（ＳＣＩＣ）与结核菌素（ＰＰＤ）０．１Ｕ皮试联合检测对菌阴肺结核的诊断价值。方法 以上述５种检测方法用于力阳肺结核３１例、健康对照５３例、非结核肺疾病３０例、初治菌阴肺结核５４例同步检测。血清免疫学检测用酶联免疫吸附试验（ＥＬＩＳＡ）。对     

噬菌体生物扩增法检测痰结核分枝杆菌的临床研究

目的评价噬菌体生物扩增(PhaB)法检测痰中结核分枝杆菌的应用价值。方法分别应用PhaB法、直接涂片法、集菌涂片法和BACTECMGIT960快速培养法检测2005年8月至10月沈阳市胸科医院53例疑诊肺结核患者痰标本中结核分枝杆菌,并对检测结果进行比较。结果PhaB法、直接涂片法、集菌涂片法、BACTECMGIT960快速培养法检出阳性标本数分别为24,11,17和22份;以培养结果为评价标准,PhaB法的敏感性、特异性、阳性预测值、阴性预测值分别为86.4%,83.9%,79.2%和89.7%;集菌涂片法和PhaB法联合检测的敏感性为90.9%,特异性为83.9%,阳性、阴性预测值分别为80.0%和92.9%。结论PhaB法检测痰中结核菌操作简便,具有较高的敏感性和特异性,可作为临床结核分枝杆菌的快速检测方法;PhaB法联合集菌涂片法进行检测可进一步提高敏感性,减少漏诊率。     

Use of amplified Mycobacterium tuberculosis direct test in respiratory samples from HIV-infected patients in Brazil

OBJECTIVE:

To compare the accuracy of the amplified Mycobacterium tuberculosis direct (AMTD) test with reference methods for the laboratory diagnosis of tuberculosis in HIV-infected patients.

METHODS:

This was a study of diagnostic accuracy comparing AMTD test results with those obtained by culture on Löwenstein-Jensen (LJ) medium and by the BACTEC Mycobacteria Growth Indicator Tube 960 (BACTEC MGIT 960) system in respiratory samples analyzed at the Bioassay and Bacteriology Laboratory of the Oswaldo Cruz Foundation Evandro Chagas Clinical Research Institute in the city of Rio de Janeiro, Brazil.

RESULTS:

We analyzed respiratory samples collected from 118 patients, of whom 88 (74.4%) were male. The mean age was 36.6 ± 10.6 years. Using the AMTD test, the BACTEC MGIT 960 system, and LJ culture, we identified M. tuberculosis complex in 31.0%, 29.7%, and 27.1% of the samples, respectively. In comparison with LJ culture, the AMTD test had a sensitivity, specificity, positive predictive value, and negative predictive value of 87.5%, 89.4%, 75.7%, and 95.0%, respectively, for LJ culture, whereas, in comparison with the BACTEC MGIT 960 system, it showed values of 88.6%, 92.4%, 83.8%, and 94.8%, respectively.

CONCLUSIONS:

The AMTD test showed good sensitivity and specificity in the population studied, enabling the laboratory detection of M. tuberculosis complex in paucibacillary respiratory specimens.     

结核感染T细胞斑点实验临床检测研究

目的探讨结核感染T细胞斑点实验（T-SPOT.TB）在临床快速诊断结核病中的应用价值。方法利用T-SPOT.TB方法检测外周血中结核感染特异的效应T淋巴细胞的频率。同时与涂片抗酸染色、BACTEC960培养及实时定量PCR方法做比对。结果164例结核病患者中,155例T-SPOT.TB阳性,提示方法敏感度为94.5％（155/164）,显著高于其他方法。60例非结核呼吸道疾病对照组中有5例阳性,20例健康对照均为阴性,方法的特异度为93.8％（75/80）。结论T-SPOT.TB方法敏感度和特异度均非常高,可用于结核病的快速诊断,尤其是对于结核病和非结核分枝杆菌病的早期鉴别。     

Characterization of mycobacterium isolates from pulmomary tuberculosis suspected cases visiting Tuberculosis Reference Laboratory at Ethiopian Health and Nutrition Research Institute,Addis Ababa Ethiopia:a cross sectional study

Objective:To characterize mycobaclerium isolates from pulmomary tuberculosis suspected cases visiting National Tuberculosis Reference Laboratory at Ethiopian Health and Nutrition Research Institute,for diagnosis of pulmonary tuberculosis from January 4 to February 22.2010 with total samples of 263.Methods:Sputum specimens were collected and processed:the deposits were cultured.Por culturing Lowenstein Jensen medium(LJ) and Mycobacteria Growth Indicator Tube(BACTEC MGIT 960) were used.Capilia Neo was used for detecting NTM isolates from isolates of BACTEC MGIT960.In Armauer Hansen Research Institute,Addis Ababa Ethiopia,Deletion typing PCR method for species identification(from confirmed Mycobacterium tuberculosis complex(MTBC) isolates by Capilia Neo) uas done.Results:Out of 263 enrolled in the study.124 and 117 ol them were positive for mycobaeterium growth by BACTEC MGIT 960 and 1.1 culture method,respectively.From BACTEC MGIT 960 positive media of 124 isolates.117 were randomly taken to perform Capilia TB Neo lest.From these 7(6%) of them were found to be NTM and 110(94%) were MTBC.From these 110 MTBC isolates,81 of them were randomly taken and run by the deletion typing RD9 PCR method of molecular technique.Out of these 78(96.3%) were found to be species of Mycobacterium tuberculosis and 3(3.7%) were found to be not in the MTBC.Regarding the types of methods of culture media.Mycobacteria Growth Indicator Tube(BACTEC MGIT 960) method was found to have excellent agreement(with kappa value ol 0.78) with the routine method of LJ.Conclusions:Pulmonary tuberculosis suspected cases visiting the National Tuberculosis Reference Laboratory at EHNR1 that were confirmed to be pulmonary tuberculosis are caused by the species of Mycobacterium tuberculosis.hence treatment regimen including pyrazinamide can be applied to the patients as the first choice in the study area in Addis Ababa.Ethiopia.There is indication of the presence of NTM in patients visiting the tuberculosis reference laboratory and this is important because NTM is known lo cause pulmonary disease similar with sign and symptom ol pulmonary tuberculosis but different in treatment.BACTEC MGIT 960 has excellent agreement with LJ media but it has high tendency of having high contamination rale unless a better decontamination method is designed.     

Evaluation of a microcolony detection method and phage assay for rapid detection of Mycobacterium tuberculosis in sputum samples

Early and rapid diagnosis of tuberculosis is necessary for both treatment and control of the disease. This study evaluated two microcolony observation techniques based on liquid and solid media and a mycobacteriophage assay, to evaluate their effectiveness in the diagnosis of pulmonary TB compared with a standard culture (BACTEC 460 and LJ medium). Middlebrook7H9 (M7H9) broth based on microcolony determination detected 57/61 positives cultures (n = 200) with a sensitivity of 93.4% and a specificity of 87.1%. M7H11 agar detected 57/62 positive cultures (n = 198) with a sensitivity of 91.9% and a specificity of 89.7%. The mycobacteriophage assay detected 98/143 (68.5%) of positive samples. The time to positivity was 48 hours in the mycobacteriophage assay versus 7 days in both the M7H9 broth and M7H11 agar. The costs in comparison with the culture (BACTEC 460 and LJ) were 33% and 48% for the microcolony and mycobacteriophage methods, respectively. Microcolony methods were rapid and cost effective compared to standard cultures. The mycobacteriophage assay, despite its lower sensitivity, has a short turn around time, and may be recommended as a screening test in countries with a low prevalence of tuberculosis.     

免疫学检测联合痰涂片和痰培养检测在活动性肺结核临床诊断中的价值

目的 分析结核感染T细胞斑点试验(T-SPOT.TB)、结核抗体、痰涂片与痰培养联合检测在活动性肺结核诊断中的临床意义。方法 收集2014年1月至2019年12月北京结核病控制研究所门诊收治的疑似活动性肺结核患者715例,最终诊断为活动性肺结核患者412例(肺结核组),非结核病患者303例(非结核组)。715例患者均行T-SPOT.TB检测、结核抗体检测及痰涂片、痰培养检查;以临床诊断结果为标准,分析4种方法单独及联合检测的临床意义。结果 肺结核组患者中,T-SPOT.TB阳性检出率为83.7%(345/412);非结核组患者中,T-SPOT.TB阳性检出率为20.8%(63/303);两组阳性检出率差异有统计学意义(χ²=2.823,P=0.000)。T-SPOT.TB对活动性肺结核检测的敏感度、特异度、阳性预测值、阴性预测值和准确度分别为83.7%(345/412)、79.2%(240/303)、84.6%(345/408)、78.2%(240/307)、81.8%[(345+240)/715];4种方法联合诊断的敏感度、特异度、阳性预测值、阴性预测值和准确度分别为93.7%(386/412)、50.8%(154/303)、72.1%(386/535)、85.6%(154/180)、75.5%[(386+154)/715]。T-SPOT.TB检测、结核抗体检测及痰涂片、痰培养检查的ROC曲线下面积(AUC)分别为0.815、0.575、0.593、0.715,四项联合检测的AUC为0.894。结论 T-SPOT.TB检测的敏感度、阴性预测值较好,T-SPOT.TB检测联合结核抗体、痰涂片和痰培养检测的敏感度、AUC较高,联合检测可提高对肺结核的诊断效能。     

TaqMan聚合酶链反应技术检测结核分支杆菌DNA及其临？…

目的 探讨ＴａｑＭａｎ聚合酶链反应（ＴａｑＭａｎ－ＰＣＲ）技术在肺结构诊断中的价值。方法 对１６８例活动性肺结核、５７例肺癌患者的痰和外周血及３４－例健康对照外周血,同时应用ＴａｑＭａｎ－ＰＣＲ、ＰＣＲ检测,并与痰涂片法、ＢＡＣＴＥＣ法及改良罗氏培养法结果进行比较。结果 ＴａｑＭａｎ－ＰＣＲ检测痰和外周血总的阳性率分别为５３．０％和６１．３％,显著高于ＰＣＲ、痰涂片法、ＢＡＴＣＴＥＣ法及改良罗氏培     

Sensitivity of an immunoenzymatic test for detection of anti-L. brasiliensis antibodies compared to other tests used for the diagnosis of American cutaneous leishmaniasis

The diagnosis of American cutaneous leishmaniasis (ACL) is frequently based on clinical and epidemiological data associated with the results of laboratory tests. Some laboratory methods are currently being applied for the diagnosis of ACL, among them the indirect immunofluorescence reaction (IIFR), the Montenegro skin test (MST), histopathological examination, and the polymerase chain reaction (PCR). The performance of these methods varies in a considerable proportion of patients. After the standardization of an immunoenzymatic test (ELISA) for the detection of IgG in the serum of patients with ACL using a crude Leishmania braziliensis antigen, the results obtained were compared to those of other tests routinely used for the diagnosis. The tests revealed the following sensitivity, when analyzed separately: 85% for ELISA IgG, 81% for PCR, 64.4% for MST, 58.1% for IIFR, and 34% for the presence of parasites in the biopsy. ELISA was positive in 75% of patients with ACL presenting a negative MST, in 84.8% of ACL patients with negative skin or mucous biopsies for the presence of the parasite, and in 100% of cases with a negative PCR. Thus, ELISA presented a higher sensitivity than the other tests and was useful as a complementary method for the diagnosis of ACL.     

4种方法联合检测在菌阴肺结核临床诊断价值的研究

目的　探讨痰聚合酶链反应——微孔板杂交技术(PCR ELISA)、抗脂阿拉伯甘露糖(LAM-IgG)抗体、结核菌素(PPD)1TU皮试以及血清可溶性白细胞介素2受体(sIL-2R)水平,4种方法联合检测对初治菌阴肺结核患者临床诊断的意义。方法 以上述4种方法检测初治菌阳肺结核57例,初治菌阴肺结核58例,非结核肺疾病41例,健康对照36例。分别进行单项与联合检测,观察初治菌阴肺结核的特异性与敏感性。结果 PCR-ELISA、LAM-IgG、TB-PPD及sIL-2R单项检测对菌阴肺结核的阳性检出率依次分别为 43.1%,37.9%,31.0%,50.0%。联合检测对菌阴肺结核的阳性检出率2联、3联及4联依次分别为 56.9%,70.7%,84.5%,与单项检测的最高阳性检出率相比由50.0%提高到84.5%;联合检测的特异性分别为92.2%,88.3%和84.4%。结论 通过4种方法联合检测能显著提高菌阴肺结核的阳性检出率,同时也保持了相对高的特异性。联合检测对于菌阴肺结核的诊断,具有实用意义。     

结核分枝杆菌特异性蛋白（TB-SA）抗体检测试剂在结核病诊断中的应用研究

目的 评价结核分枝杆菌特异性蛋白(tuberculosis specific antigen, TB-SA)抗体检测试剂在结核病中的应用价值。 方法 以天津市和平区结核病控制中心、山东省烟台芝罘区肺科医院和河南省南阳市卧龙区结核病防治中心为研究现场,连续纳入2012年4月至10月门诊就诊的所有肺结核疑似患者944例,同时纳入110名健康志愿者作为对照。对所有纳入患者及健康志愿者进行痰涂片、培养、结核菌素试验（PPD）和胸部X线检查,签署知情同意书后留取血清进行TB-SA抗体检测。痰涂片采用萋-尼（Ziehl-Neelsen）染色法,培养采用接种酸性罗氏固体培养基培养。现场数据由双人录入,在国家结核病参比实验室统一整理分析。 结果755例确诊的活动性结核病患者,TB-SA抗体检测法阳性率为74.8% (565/755,95%CI＝71.7%～77.9%),远高于涂片阳性率25.6%（193/755）(χ²=366.59,P<0.0001) 和培养阳性率39.6%（299/755）(χ²=190.12,P<0.0001)。在培养阳性结核病患者中,TB-SA抗体检查敏感度为88.5% (255/288,95%CI＝84.8%～92.2%)。在菌阴活动性结核病患者中,TB-SA抗体检查敏感度为68.0% (310/456,95%CI＝63.7%～72.3%)。TB-SA抗体检测法在活动性结核病患者中的阳性预测值为92.3% (565/612,95%CI＝90.2%～94.4%),在健康人群中检测特异度为97.3% (95%CI＝94.3%～100.3%)。 结论TB-SA抗体检测法在结核病患者中阳性检出率显著高于涂片和培养,适用于结核病,特别是菌阴结核病的诊断;TB-SA抗体检测法诊断结核病的特异度高,可用于人群健康体检。     

快速免疫色谱实验诊断可疑肺结核病人的评价

目的评价基于结核分支杆菌38KDa等五种抗原的快速免疫色谱实验(澳大利亚ICT TB)对可疑肺结核的临床诊断价值?方法以初诊可疑肺结核患者125例为受试对象,同时做痰涂片?培养,血清ICT TB以及胸片检查?结果总的敏感性为45%?特异性为100%?结论此试验不能完全代替痰涂片抗酸染色检查,但二者联合使用,可使敏感性提高到63.6%.     

Recovery rates of mycobacterium from suspected extra-pulmonary tuberculosis patients using liquid culture at a tertiary referral centre of India

Tuberculosis still remains a serious public health problem in developing countries. Rapid isolation of mycobacteria is critical for accurate diagnosis and management of tuberculosis. In the present study BACTEC MGIT 960 system was evaluated against Lowenstein Jensen (LJ) medium for isolation of mycobacteria from different extra-pulmonary specimens (N = 371). The samples were processed using NaOH-NALC method and inoculated in BACTEC MGIT and on LJ medium. The BACTEC MGIT 960 system detected 93 (25.06%) samples positive for acid fast bacilli and by LJ only 38 samples (10.24%) was positive. Furthermore, total 99 (26.68%) samples were detected positive by both the culture methods. The mean turnaround time to detection of mycobacteria by MGIT 960 were significantly less (12.4 days) as compared with LJ (22.76 days). In conclusion, BACTEC MGIT 960 system is more sensitive and rapid culture system for isolation of mycobacteria. However LJ culture method also suggested to further increase the detection rate of EPTB cases.     

Diagnostic utility of cerebrospinal fluid studies in patients with clinically suspected tuberculous meningitis.

OBJECTIVE: To compare yields of cerebrospinal fluid (CSF) studies in the diagnosis of tuberculosis meningitis (TBM). DESIGN: Prospective laboratory study, Kenyatta National Hospital, Kenya. STUDY POPULATION: Consecutive patients with 1) headache, neck stiffness and altered consciousness for more than 14 days, 2) above features plus evidence of tuberculosis elsewhere in the body, and 3) on standard antimeningitic drugs for one week without response, were included. Those with contraindications to lumbar puncture, confirmed causes of meningitis (except TB) and on anti-tuberculosis treatment were excluded. METHODS: CSF cell counts, glucose and protein were assayed. CSF was stained on ZN, cultured on LJ and BACTEC and subjected to PCR and LCR for Mycobacterium tuberculosis DNA sequences. Positive tests for M. tuberculosis were classified as definite and the rest as probable TBM. RESULTS: Fifty-eight patients with a mean age of 33.0 years were recruited. Mean CSF cell count was 71/microl and CSF lymphocyte count up 67%. Mean CFS protein and glucose were 2.10 g/l and 2.05 mmol/l, respectively. BACTEC was positive in 20 cases, LJ 12, LCR eight, and PCR and ZN one each. Twenty-six patients had definite and 32 probable TBM. Patients with definite TBM had significantly higher CSF protein, lower CSF glucose, higher CSF cell count and lower CSF lymphocytes. CONCLUSION: TBM can be confirmed in half of clinically suspected cases. More sensitive tests for confirmation of TBM are required.