Rapid Diagnosis Of Extrapulmonary Tuberculosis Research Articles

Usefulness of Xpert MTB/RIF Ultra for rapid diagnosis of extrapulmonary tuberculosis in Tunisia

Extrapulmonary tuberculosis (EPTB) remains a challenging diagnosis. The purpose of this study was to assess the accuracy of Xpert MTB/RIF Ultra (Cepheid, USA) for rapid diagnosis of EPTB in Tunisia. Eight hundred and forty-seven extrapulmonary samples collected from 2017 to 2021, were subjected to Xpert MTB/RIF Ultra. Microscopy and culture were performed for all the specimens. The accuracy of Xpert Ultra was evaluated in comparison to the culture. Xpert Ultra diagnosed EPTB with a global sensitivity of 80.66% (74.3–85.75) and specificity of 70.87% (67.31–74.20). The molecular test was most accurate when performed in cerebrospinal fluids, bones and joints and cutaneous specimens showing a sensitivity of 100% and a specificity ranging from 70.60 to 91.11%. In lymph node samples comprising aspirates and biopsies, the sensitivity of Xpert Ultra was high 87.50% (77.23–93.53), however, the specificity was 51.08% (44.67–57.46). For pleural samples, the Xpert Ultra sensitivity was 77.50% (68.34–84.68) ranging from 71.43 to 80% in pleural biopsies and fluids respectively. The specificity in all pleural specimens was 79.56% (74.40–83.91). Xpert Ultra showed promise in the diagnosis of EPTB. The performances varied according to the site of the disease. The test may be more valuable if used in combination with other diagnostic modalities.

Xpert MTB/RIF Ultra for the rapid diagnosis of extrapulmonary tuberculosis in a clinical setting of high tuberculosis prevalence country and interpretation of ‘trace’ results

To evaluate the diagnostic performance of Xpert MTB/RIF Ultra (Ultra) for the diagnosis of extrapulmonary tuberculosis (EPTB) from different types of extrapulmonary specimens in comparison with culture and composite microbiological reference standard (CRS). A total of 240 specimens were prospectively collected from presumptive EPTB patients between July 2021–January 2022 and tested by Ultra, Xpert, culture and acid-fast bacilli (AFB) smear microscopy. Out of 240 specimens, 35.8 %, 20.8 %, 11.3 %, and 7.1 % were detected as Mycobacterium tuberculosis complex by Ultra, Xpert, culture and AFB microscopy, respectively. An additional 15.0 % cases were detected by Ultra compared to Xpert MTB/RIF (Xpert) assay. A total of 28 (11.7 %) cases were identified as ‘trace’ category by Ultra with indeterminate rifampicin resistance result; of which 36.4 % were clinically confirmed as EPTB. Compared to culture, the sensitivity and specificity of Ultra and Xpert were 100 % and 72.3 %; 92.6 % and 88.3 %, respectively. In comparison with CRS, these were respectively: 98.9 % and 100 %; 57.5 % and 100 %. For individual category of specimens, sensitivity of Ultra was 100 % with varying specificity. We found that Ultra was highly sensitive for the rapid diagnosis of EPTB and has extensive potential over current diagnostics in high TB burden countries, but ‘trace’ results should be interpreted with caution.

Performance Comparison of GeneXpert MTB/RIF and ProbeTec ET Tests for Rapid Molecular Diagnosis of Extrapulmonary Tuberculosis in a Low TB/MDR-TB Incidence Country

Objective: This study evaluated the performance of GeneXpert MTB/RIF (Xpert) and ProbeTec ET (PTec-ET) assays in diagnosing extrapulmonary tuberculosis (EPTB) in Kuwait. Materials and Methods: We tested nonrespiratory clinical specimens (n = 3,995) collected from 3,995 patients suspected to have EPTB. These included cavitary fluids (n = 2,054), fine-needle aspirate (FNA)/pus/tissue biopsy (n = 1,461), urine (n = 302), cerebrospinal fluid (CSF, n = 118), and others (n = 60). All specimens were processed for acid-fast bacilli (AFB), culture in mycobacteria growth indicator tube 960 system, and nucleic acid detection by Xpert and PTec-ET according to manufacturer’s instructions. Results: Of 3,995 specimens, 95 were AFB-positive, 403 were culture-positive, and an additional 86 samples had histopathology suggestive of TB. Using culture as reference, the sensitivity and specificity values were 88.33 and 97.3% for Xpert and 72.95 and 97.80% for PTec-ET, respectively. Although performance of both tests was comparable in AFB-positive samples, Xpert detected significantly more cases in culture-positive samples. Among culture-negative samples, Xpert detected 18 more cases including 16 with histopathological evidence of TB. Lowest positivity was detected for both tests in cavitary fluids. Xpert performed better than PTec-ET in culture-positive FNA/pus/tissue biopsy and CSF samples. Conclusions: Although performance of both tests was suboptimal for AFB-negative/culture-positive samples, Xpert performed better than PTec-ET and also detected more cases of AFB-negative/culture-negative/histopathology-positive samples. PTec-ET was positive in 3, while Xpert was positive in all 6 culture-positive CSF specimens for rapid diagnosis of TB meningitis. Xpert was thus superior to PTec-ET or smear microscopy in rapid diagnosis of EPTB.

Xpert MTB/RIF ultra for rapid diagnosis of extrapulmonary tuberculosis in a high-income low-tuberculosis prevalence setting

The diagnosis of extrapulmonary tuberculosis (EPTB) is often challenging due to paucibacillary nature of the disease. Xpert MTB/RIF Ultra (Ultra) has been developed to improve detection of Mycobacterium tuberculosis complex (MTC) in paucibacillary specimens. The objective of the study was to assess the performance of Ultra for the diagnosis of EPTB in a high-income low TB prevalence country. Extrapulmonary samples received for TB diagnostics at two hospitals in Norway between January 2015 and January 2016 were prospectively and consecutively included. Defrosted samples were subjected to Ultra. Culture and routine PCR tests were used as reference standard. A total of 82 samples, 10 culture and/or routine PCR positive (confirmed TB) samples and 72 culture and routine PCR negative samples were included in analysis. The overall sensitivity and specificity of Ultra were 90% (9/10, 95% CI 56–100) and 99% (71/72, 95% CI 93–100), respectively. Ultra was positive in 6/7 smear negative confirmed TB samples. To conclude, Ultra showed a high sensitivity and specificity in extrapulmonary specimens and may contribute to a rapid diagnosis of EPTB in a low TB prevalence setting.

Multi-targeted loop mediated amplification PCR for diagnosis of extrapulmonary tuberculosis

AimsThe present study was conceived to evaluate multi-targeted loop mediated amplification (MLAMP) for the rapid diagnosis of extrapulmonary tuberculosis (EPTB). Methods and resultsA total of 700 patients were included who were classified into 2 groups: Group 1 (n = 400) included a 100 culture confirmed EPTB patients and 300 culture negative, suspected EPTB patients. Group 2 (n = 300) included negative controls from non-tubercular patients. All samples were subjected to Ziehl-Neelsen microscopy, solid culture on Lowenstein Jensen media, Polymerase chain reaction (PCR) targeting IS6110 gene and LAMP targeting both IS6110 and MPB64 individually and as MLAMP. The overall sensitivity of microscopy, culture, IS6110 PCR, IS6110 LAMP, MPB64 LAMP and the MLAMP assay were 12%, 25%, 72.5%, 80% and 86.6% respectively and the specificity of all the tests was 100%. ConclusionMLAMP is a rapid robust tool for the diagnosis of EPTB and utilizing two targets for M. tuberculosis can improve the overall sensitivity and increase the yield of detection from extrapulmonary samples. The rapidity, ease of performance and low cost make MLAMP an excellent alternative in low-income, resource limited settings.

Contribution of Real-Time Xpert MTB/RIF Testing to Establishing Early Diagnosis of Pediatric Extrapulmonary Tuberculosis in a Nonendemic Setting: A Case Series.

Microbiologic confirmation of pediatric extrapulmonary tuberculosis remains challenging, leading to diagnostic delays. In our retrospective case series, real-time molecular testing (Xpert MTB/RIF) on respiratory and extrapulmonary specimens resulted in a more rapid diagnosis of extrapulmonary tuberculosis in a nonendemic, high resource setting.

Comparison of CapitalBio™ Mycobacterium nucleic acid detection test and Xpert MTB/RIF assay for rapid diagnosis of extrapulmonary tuberculosis

The CapitalBio™ Mycobacterium nucleic acid detection test is a real-time fluorescent polymerase chain reaction and TaqMan probe technology test for rapid diagnosis of extrapulmonary tuberculosis (EPTB). This test had moderate sensitivity and high specificity for EPTB, like that of Xpert MTB/RIF, especially for lymph node, chest wall, and purulent fluid samples.

Assessment of the Xpert MTB/RIF Ultra assay on rapid diagnosis of extrapulmonary tuberculosis

ObjectiveTo evaluate the diagnostic performance of Xpert MTB/RIF Ultra for EPTB (Extrapulmonary Tuberculosis) patients on different types of extrapulmonary specimens from different anatomic sites. MethodsPatients with suspected EPTB were prospectively included, extrapulmonary specimens were collected and subjected to culture, Xpert and Xpert Ultra assays in accordance with relevant guidelines. ResultsA total of 225 cases were included which contained 200 EPTB cases (43 culture-positive EPTB, 157 culture-negative EPTB which were diagnosed based on pathological results and a satisfied response to anti-TB treatment) and 25 non-EPTB cases. Sensitivities of Xpert Ultra and Xpert for culture-positive cases were 83.7% (95%CI, 68.7–92.7) and 67.4% (95% CI, 51.3–80.5) respectively. Specificities of Xpert Ultra and Xpert were 92.0% (95% CI, 72.5–98.6) and 96.0% (95% CI, 77.7–99.8) respectively. The sensitivities of Xpert Ultra, Xpert and culture for 200 EPTB cases were 52.5% (105/200, 95% CI, 45.4–59.6), 34.0% (68/200, 95% CI, 27.6–41.1) and 21.5% (43/200, 95% CI, 16.2–28.0) respectively. By comparison among different types of specimens, Xpert Ultra can detect 78.9% (56/71) of EPTB on fine-needle aspiration (FNA) tissues which was higher than that on pleural fluid (43.7% (45/103), p<0.05. ConclusionsXpert Ultra assay had a higher sensitivity than those of Xpert and culture on extrapulmonary specimens, which could be a promising approach for rapid EPTB diagnosis.

Diagnosis of Concurrent Pulmonary Tuberculosis and Tuberculous Otitis Media Confirmed by Xpert MTB/RIF in the United States.

Tuberculosis (TB) remains an important cause of infectious morbidity in the United States (US), necessitating timely and accurate diagnosis. We report a case of concurrent pulmonary and extrapulmonary TB presenting as tuberculous otitis media in a hospitalized US patient admitted with cough, night sweats, and unilateral purulent otorrhea. Diagnosis was made by smear microscopy and rapidly confirmed by Xpert MTB/RIF-a novel, automated nucleic acid amplification test for the rapid detection of drug-susceptible and drug-resistant TB. This case adds to the growing body of evidence validating Xpert MTB/RIF as an effective tool for the rapid diagnosis of extrapulmonary TB, even in low TB-prevalence settings such as the US, when testing is performed on non-respiratory specimens.

Evaluation of the performance of 2 DNA-based methods for the detection of extra-pulmonary tuberculosis in comparison with the conventional culture technique

IntroductionDiagnosing extra-pulmonary tuberculosis continues to be a challenge for both infectious disease specialists and microbiologists. ObjectivesThis prospective study was done to evaluate the performance of two DNA-based methods for the detection of extra-pulmonary tuberculosis in comparison with the conventional culture technique. MethodsAll extra-pulmonary specimens received by the Kuwait National Tuberculosis Reference from October 2011 until August 2013 were included in the study. Smears were stained by Ziehl Neelson (Merck, Germany) followed by inoculation of the specimens into GeneXpert MTB/RIF assay (Cepheid, USA), ProbTec ET PCR (Becton Dickinson) and MGIT 960 (Becton Dickinson). Urine was inoculated into Lowenstein Jensen media (MAST). ResultsA total of 1674 extra-pulmonary specimens (pleural fluid 553, ascetic fluid 194, cerebrospinal fluid [CSF] 85, Urine 67, other sterile body fluids 153, fine needle aspirates [FNA] 301, pus 181, tissue 102, swabs 27 and stool 11) were evaluated. Out of 155 extra-pulmonary specimens that grew Mycobacterium tuberculosis (MTB) by culture, 143 were positive by GeneXpert compared with 128 by ProbTec with a sensitivity of 92% and 83%, respectively. Out of 1517 specimens that did not grow by culture, 52 were detected by GeneXpert while 46 were detected by ProbTec with specificity of 96.5% and 96.9%, respectively. All the 4 smear-negative CSF samples which grew MTB were positive by GeneXpert with a sensitivity of 100% compared with only 2 detected by ProbTec with a sensitivity of 50%. Additionally, all CSF specimens that did not grow by culture were negative by both the molecular methods showing 100% specificity. Of the 3 smear-positive urine specimens that grew by culture, all were positive, and of the 64 samples that did not grow by culture, all were negative by both the molecular methods with a sensitivity and specificity of 100%. For other sterile body fluids the sensitivity and specificity of both the methods were 68% and 99%, respectively. Finally, for FNA, pus and tissue, the sensitivity of GeneXpert was 97% compared with 86% for ProbTec. ConclusionDNA-based technology looks promising for the rapid diagnosis of extra-pulmonary tuberculosis with an overall better performance of GeneXpert over ProbTec.

Direct and Rapid Diagnosis of Extra-Pulmonary Tuberculosis in Archival Tissue by Nested and Touchdown PCR

Aims: To identify and differentiate mycobacterium spp. in archival formalin-fixed, paraffinembedded tissue by PCR to supply additional differential diagnostic method for Mycobacterium infections, where tuberculosis had been tested for by histopathological methods but without culturing. Place and Duration of Study: Department of Medical Laboratory Sciences, Department of Pathology and Microbiology (Faculty of Medicine) and King Abdulla University Hospital, between January 2004 and July 2010. Methodology: Fifty-six extra-pulmonary specimens of formalin-fixed, paraffin-embedded tissue obtained from patients showing granulomatus inflammation and/or other histopathologic features. Specimens were analyzed by a hemi-nested PCR assay targeting the gene encoding for 16S ribosomal RNA, which is common to all mycobacteria spp. The PCR positive specimens were amplified by a touch-down PCR targeting a fragment in the insertion sequence IS6110 specific to Mycobacterium tuberculosis complex. Results were compared to acid fast bacilli stain and with histopathology of each specimen. Results: M. tuberculosis complex DNA was detected in 27 (48.2%) specimens, and nonOriginal Research Article Article British Microbiology Research Journal, 4(5): 530-539, 2014 531 tuberculous mycobacteria in four specimens, compared to 10 (18%) specimens that were positive by acid fast staining. The positive cases were observed more in the lymph nodes, and pleural specimens. Conclusions: This study is among few studies to use the touch-down PCR assay as a promising auxiliary tool for the diagnosis of extra-pulmonary tuberculosis in archival tissue specimens. It could be used in conjunction with routine laboratory tests (e.g., cultures, acid fast staining) and clinical criteria of the patient to increase the accurate diagnosis of such cases. It is also recommended that culture be routinely done for all tuberculosis suspected cases.

Using likelihood ratios to estimate diagnostic accuracy of a novel multiplex nested PCR in extra-pulmonary tuberculosis

A tertiary care centre in Mumbai with a referral bias towards treatment failures. To standardise and evaluate a novel single tube multiplex nested polymerase chain reaction (PCR) targeting insertion sequence (IS) 6110, mpb64, rrs and rpoB genes for rapid diagnosis of extra-pulmonary tuberculosis (EPTB). The PCR assay was evaluated among 489 consecutive consenting patients, and results were compared against a composite reference standard comprising smear microscopy, culture, clinical symptoms, radiological scan and histology. PCR assay reported a pooled sensitivity of 94.5% (242/256, 95%CI 91-97): 91.9% (125/136, 95%CI 86-96) for smear-negative composite reference standard (CRS) positive cases and 97.5% (117/120, 95%CI 93-99) for smear-positive CRS-positive cases. The PCR positivity rate increased from 91.7% (235/256, 95%CI 88-95) when presence of IS6110 was considered alone for reporting a test as positive to 94.5% (242/256, 95%CI 91-97) when used in combination with other three gene targets, with a specificity of 96.4% (212/220, 95%CI 93-98). A positive likelihood ratio of 26 (95%CI 13-51) and a negative likelihood ratio of 0.06 (95%CI 0.03-0.09) makes the test useful for ruling out and ruling in the disease. Culture should not be replaced by PCR as a gold standard; however, PCR can be used as a rapid, accurate tool in the diagnosis of EPTB.

Comparison of Two Molecular Methods for Rapid Diagnosis of Extrapulmonary Tuberculosis

Application of real-time PCR for the detection of Mycobacterium tuberculosis enables results to be obtained in about 2 h. A total of 340 nonrespiratory samples were processed using two real-time PCR assay kits: Xpert MTB/RIF and Cobas TaqMan MTB. The sensitivity and specificity of the Xpert assay were 95% and 100%, respectively, compared to 78% and 98% for the Cobas assay.

Rapid Diagnosis of Extrapulmonary Tuberculosis Using Nucleic Acid Amplification Tests: What is the Evidence?

Madhukar Pai† & Daphne I Ling †Author for correspondence Department of Epidemiology, Biostatistics & Occupational Health, McGill University, Respiratory Epidemiology & Clinical Research Unit, Montreal Chest Institute, 1020 Pine Avenue , West Montreal, H3A 1A2, Canada Tel.: +1 514 398 5422; Fax: +1 514 398 4503; madhukar.pai@mcgill.ca ‘Because of the paucibacillary nature of extrapulmonary disease, the diagnosis of extrapulmonary TB is not easy to establish, especially in developing countries.’

Diagnosis of Extrapulmonary Tuberculosis by Smear, Culture, and PCR Using Universal Sample Processing Technology

Definitive and rapid diagnosis of extrapulmonary tuberculosis is challenging since conventional techniques have limitations. We have developed a universal sample processing (USP) technology for detecting mycobacteria in clinical specimens. In this study, this technology was evaluated blindly on 99 extrapulmonary specimens collected from 87 patients. USP-processed specimens were submitted to smear microscopy for detection of acid-fast bacilli (AFB), culture, and two PCR tests targeting devR (Rv3133c) and IS6110 gene sequences. On the basis of clinical characteristics, histology and cytology, conventional microbiology results, and response to antitubercular therapy, 68 patients were diagnosed with tuberculosis. Although USP smear and culture were significantly superior to conventional microbiology, which was not optimized (P < 0.0001), these approaches fell short of PCR tests (P < 0.0001). The low yields by smear and culture are attributed to the paucibacillary load in the specimens. The highest sensitivity in PCR was achieved when devR and IS6110 test results were combined; the sensitivity and specificity values were 83 and 93.8%, 87.5 and 100%, and 66.7 and 75%, respectively, in pleural fluid, needle-biopsied pleural tissue, and lymph node specimens. In conclusion, the application of USP technology, together with clinicopathological characteristics, promises to improve the accuracy and confidence of extrapulmonary tuberculosis diagnosis.

Clinical Evaluation of the Gen-Probe amplified mycobacterium tuberculosis direct test for rapid detection of Mycobacterium tuberculosis in select nonrespiratory specimens.

The performance of the Amplified Mycobacterium Tuberculosis Direct Test (MTD; Gen-Probe, Inc., San Diego, Calif.) for rapid diagnosis of extrapulmonary tuberculosis was evaluated by testing 178 nonrespiratory specimens from 158 patients. Criteria for specimen inclusion were (i) a positive smear for acid-fast bacilli (n = 54) and (ii) the source if the smear was negative (tissue biopsies and aspirates and abscess material were tested; n = 124). Results were compared to those of mycobacterial culture; clinical history was reviewed when MTD and culture results disagreed. Forty-eight specimens (27.0%) were positive for mycobacteria, including 23 Mycobacterium tuberculosis complex specimens; of which 21 were smear positive. Twenty-five specimens were MTD positive; 20 of these grew M. tuberculosis complex. All of the five MTD-positive, M. tuberculosis complex culture-negative specimens were considered truly positive, based on review of the medical record. Of the three MTD-negative, M. tuberculosis complex culture-positive specimens, two contained inhibitory substances; one of the two was smear positive. Excluding the latter specimen from analysis, after chart review, the sensitivity, specificity, and positive and negative predictive values of the MTD were 92.6, 100, 100, and 98.7%, respectively, by specimen and 89.5, 100, 100, and 98.6% by patient. Given the few smear-negative samples from patients with extrapulmonary tuberculosis in our study, additional similar studies that include more smear-negative, M. tuberculosis complex culture-positive specimens to confirm our data are desirable.

Rapid diagnosis of extrapulmonary tuberculosis by ligase chain reaction amplification.

A rapid amplification-based test for the diagnosis of extrapulmonary tuberculosis, the LCx Mycobacterium tuberculosis Assay from Abbott Laboratories, was evaluated. Results from the LCx M. tuberculosis Assay were compared with those from culture and the final clinical diagnosis for each patient. A total of 526 nonrespiratory specimens from 492 patients were tested. The specimens included urine; feces; lymph node exudates; pleural, cerebrospinal, articular, and ascitic fluids; tissue biopsies; gastric aspirates; purulent exudates; blood; and bone marrow aspirates. After combination of the culture results and the patient's clinical data, a total of 135 specimens were collected from 122 patients with a diagnosis of extrapulmonary tuberculosis. The sensitivity, specificity, and positive and negative predictive values for the LCx M. tuberculosis Assay were 77.7, 98.7, 95.2, and 93.1%, respectively; these values rose in resolved cases of TB to 78.5, 100, 100, and 93.1%, respectively. For 37 (27.4%) specimens from patients smear positive for the disease and 98 (72.6%) specimens from patients smear negative for the disease, the sensitivities of the LCx M. tuberculosis Assay were 100 and 71.1%, respectively. Statistically significant differences (P < 0.01) in sensitivities were found between culture and the LCx M. tuberculosis Assay. These differences were even greater among smear-negative specimens. The results demonstrate that the LCx M. tuberculosis Assay will provide rapid and valuable information for the diagnosis of extrapulmonary tuberculosis.