MGIT Culture Research Articles

Metagenomic Next-Generation Sequencing (mNGS) in cerebrospinal fluid for rapid diagnosis of Tuberculosis meningitis in HIV-negative population

ObjectiveMetagenomic Next-Generation Sequencing (mNGS) has been applied as a novel method of detection pathogens for infectious diseases, but its value in the rapid diagnosis of tuberculous meningitis(TBM)has not been clarified based on large samples. MethodsA retrospective analysis was conducted on 51 inpatients with suspected TBM who underwent mNGS and four other tests in cerebrospinal fluid (CSF). ResultsAmong 51 included patients, 45 cases were diagnosed as TBM (38 definite, 5 probable, 2 possible) and 6 cases as non-TBM. Using final diagnosis as reference standard, the sensitivity, specificity, PPV (positive predictive value), and NPV (negative predictive value) of mNGS in CSF for TBM were 84.44%(38/45, 69.94%–93.01%), 100%(6/6, 51.68%–100%), 100%(40/40, 88.57%–100%) and 46.15%(6/13, 20.40%–73.88%). The diagnostic sensitivity of mNGS(84.4%)was significantly higher than that of AFB (0%, P = 0.000), MGIT960 culture(22.2%, P = 0.000), MTB PCR(24.4%, P = 0.000) and Xpert MTB/RIF(40%, P = 0.000). The ROC curve showed that CSF protein quantification and CSF cell count might be valuable in the prediction of NGS positive detection of MTB (Mycobacterium tuberculosis). ConclusionCSF mNGS had high sensitivity, specificity and PPV in the diagnosis of TBM. Patients with a significant increase in CSF cell number and protein quantification might have a higher likelihood of positive MTB detection of NGS.

Diagnostic value of polymerase chain reaction targeting insertion sequence IS1081 for the diagnosis of pediatric tuberculosis

Background: Aim of this study was to evaluate the efficacy of PCR targeting IS1081in diagnosis of pediatric tuberculosis and compare the results with MGIT culture.Methods: This prospective study was conducted in the department of pediatrics, S.N. medical college, Agra. 100 subjects (28 pulmonary 72 extra pulmonary) were registered in study. The specimens obtained from these cases were subjected to Ziehl–Neelsen staining (ZN), MGIT 960 TB culture and PCR targeting insertion sequence IS1081. Sensitivity, specificity, PPV and NPV of PCR were calculated in pulmonary and extra pulmonary specimens. The results of PCR IS1081 were compared to MGIT culture.Results: Microscopy with ZN staining was positive in 12 (12%) samples. MGIT culture was positive in 44% samples with maximum positivity in sputum (70%). PCR IS1081 has shown 93.3% sensitivity in pulmonary tuberculosis, while PCR IS1081 has shown 93.1% sensitivity in extra pulmonary tuberculosis. In diagnosis of childhood tuberculosis PCR IS1081 was found to be statistically significant (p value <0.05) as compared with MGIT culture. Result was statistically significant (p value <0.05) in CSF samples only.Conclusions: The study concluded that the PCR targeting sequence IS1081 technique is the most sensitive technique for a quick identification of MTB in pulmonary and extra pulmonary tuberculosis.

A pilot study: VereMTB detection kit for rapid detection of multidrug-resistant mycobcterium tuberculosis in clinical sputum samples.

The performance of VereMTBTM Detection Kit for detection of multidrug-resistant tuberculosis (MDR-TB) was validated by using 124 sputum samples. Comparing with MGIT culture, the sensitivity and specificity of VereMTB Detection Kit for MTBC detection were 97.0% and 98.3%, respectively. Compared with MGIT DST, the sensitivity and specificity of VereMTB Detection Kit for RIF resistance detection were 85.7% and 93.9%, respectively, and the sensitivity and specificity of VereMTB Detection Kit for INH resistance detection were 75.0% and 95.7%, respectively. 6 NTM samples were also detected and identified correctly. The VereMTB Detection Kit can detect MDR-TB rapidly and accurately in sputum samples from TB suspects.

Comparison Study of GENEXPERT versus TB MGIT Culture in Extra Pulmonary Tuberculosis

Aims and objectives: To compare the diagnostic yield of Extra Pulmonary Tuberculosis, in terms of MTB isolation & detection of drug resistance via GENEXPERT & MGIT-DST culture methods. Materials and Methods: This was a prospective observational study carried out in Department of Pulmonary medicine, D.Y. Patil Hospital, Navi Mumbai. Study participants were patients above 18 years of age who had extra pulmonary tuberculosis and who were not already on Anti tuberculosis treatment in D.Y. Patil Hospital, Nerul, Navi Mumbai and willing to participate in the study and meeting all the inclusion criteria of the study. Study duration was from the date of approval by institutional ethics committee to October 2019.Sample size was 150 patients satisfying the inclusion criteria. Results: In our study, 28 % of all extra pulmonary samples were tested positive for TB MGIT culture out of which 35.2 % showed Resistance to 1st line ATT drugs on DST where as 39.33% was tested positive with Gene expert out of which 22.47% showed Rifampicin Resistance. Sensitivity of MGIT was 28.00 % and specificity was 39.50 %.Sensitivity of Genexpert was 39.33% and specificity was 26.5%. Conclusion: Our findings suggest that Gene Xpert may have a role in EPTB diagnosis in addition to PTB, particularly in low income/high-burden settings, where facilities for mycobacterial culture are limited. But Gene Xpert can detect only Rifampicin resistance where as DST by BACTEC MGIT AFB Culture detects other ATT drugs sensitivity too. Also the test results of MTB detected in GeneXpert in extra pulmonary samples was shown as low and very low based on the CT range (high, 28) as most of the extra pulmonary samples are pauci bacillary; hence the result is not totally reliable. Therefore, it should be confirmed by phenotypic DST by BACTEC MGIT Culture.

Diagnostic tests for tuberculous meningitis

Tuberculous meningitis is the most serious manifestation of tuberculosis, with mortality in approximately 50% of HIV co-infected people. 1 Marais S Pepper DJ Schutz C Wilkinson RJ Meintjes G Presentation and outcome of tuberculous meningitis in a high HIV prevalence setting. PLoS One. 2011; 6e20077 Crossref PubMed Scopus (69) Google Scholar A major factor contributing to the poor outcome of tuberculous meningitis is delayed diagnosis due to a lack of rapid, accurate diagnostic tests. Until recently, these tests were restricted to smear microscopy of cerebrospinal fluid (CSF) and microbiological culture. The former tends operationally to be of low sensitivity and the latter often renders a result too late to be clinically meaningful. The diagnosis of drug-resistant disease presents further difficulties. Xpert MTB/RIF Ultra for the diagnosis of HIV-associated tuberculous meningitis: a prospective validation studyXpert Ultra detected tuberculous meningitis with higher sensitivity than Xpert and MGIT culture in this HIV-positive population. However, with a negative predictive value of 93%, Xpert Ultra cannot be used as a rule-out test. Clinical judgment and novel highly sensitive point-of-care tests are still required. Full-Text PDF Open AccessXpert MTB/RIF Ultra versus Xpert MTB/RIF for the diagnosis of tuberculous meningitis: a prospective, randomised, diagnostic accuracy studyXpert Ultra was not statistically superior to Xpert for the diagnosis of tuberculous meningitis in HIV-uninfected and HIV-infected adults. A negative Xpert Ultra or Xpert test does not rule out tuberculous meningitis. New diagnostic strategies are urgently required. Full-Text PDF Open Access

Comparison of Lowenstein-Jensen medium and MGIT culture system for recovery of Mycobacterium tuberculosis from abscess samples

PurposeIn this study, our aim was to assess Lowenstein-Jensen (L-J) medium and MGIT culture system for recovery of Mycobacterium tuberculosis (MTB) from abscess samples in skeletal tuberculosis (TB) cases. MethodsAbscess samples were collected from patients suggestive of skeletal TB in Beijing Chest Hospital for laboratory examination, including smear microscopy, L-J culture and MGIT culture. ResultsOf the 232 abscess samples, 72 (31.0%) were culture-positive for mycobacteria. Of 72 isolates recovered, 94.4% were detected in MGIT 960 and 75.0% on L-J medium. MGIT could recover significantly higher rate of MTB isolates from smear-positive specimens than L-J medium. The mean time to detection of MTB in MGIT 960 was significantly lower than that on L-J medium. ConclusionThe BACTEC MGIT 960 outperforms the conventional L-J medium in recovering MTB from abscess samples. The combination of MGIT and L-J method also increases the overall recovery rate of MTB in culture.

Respiratory Specimens for the Diagnosis of Pediatric Pulmonary Tuberculosis: A Comparative Assessment

The objective was to assess the utility of induced sputum (IS) as an alternative or add-on to gastric lavage and aspirate (GLA) as the respiratory specimen to diagnose pulmonary tuberculosis (PTB) in children. After consent, fifty children aged 0–14 years with suspected PTB were enrolled. Sputum/induced sputum and gastric lavage from the participants were collected on two consecutive days. Bronchoalveolar lavage was also done if indicated. The microbiological isolation in these specimens by Smear, MGIT culture, or Xpert MTB/RIF assay was compared. Based on the clinical, radiological, and microbiological profile, 23/50 children were diagnosed with PTB. If GLA was used alone, the yield was 11 cases (47.8%). If sputum (expectorated or induced) was used alone, the yield was 12 cases (52.1%). The difference in the two yields was not statistically significant (p = 1). The combined yield of GA and sputa was 69.5%, which was significantly more than when either of the specimens was used alone. Sputum was induced in 11 children, who could not expectorate. GLA and IS were compared, as these are the typical specimens obtainable in children who cannot expectorate. The yield of GLA was 4/11(36.36%) in these samples, and it was 5/11 (45.45%) for IS. Combining GLA and IS increased the yield to 7/11(63.6%) which amounted to a 27.2% increase from using GLA alone. IS is a valuable tool to increase the microbiological yield for the diagnosis of PTB in young children who cannot expectorate and should be considered routinely.

Multicenter evaluation of the acid-fast bacillus smear, mycobacterial culture, Xpert MTB/RIF assay, and adenosine deaminase for the diagnosis of tuberculous peritonitis in China

BackgroundThe aim of this study was to assess the validity of GeneXpert MTB/RIF (Xpert) and adenosine deaminase (ADA) in the diagnosis of tuberculous peritonitis (TBP). MethodsThe laboratory results of peritoneal effusion (PE) specimens from patients with symptoms suggestive of TBP, attending three TB specialized hospitals between January 2016 and December 2018, were included retrospectively. Clinically diagnosed TBP was set as the gold standard to evaluate the performance of these methods. ResultsIn total, 191 individuals presenting with symptoms suggestive of TBP were included for analysis. The sensitivities of MGIT culture and Xpert were 17.2% and 18.3%, respectively. In addition, the TBP cases (69.8±6.0U/l) had higher amounts of ADA in their PE samples than the non-TBP cases (12.6±1.6U/l; p<0.01). Using a threshold of 31.5U/l to differentiate the TBP group from non-TBP group, the ADA assay provided a sensitivity of 89.6% and a specificity of 92.1%. The mean ADA concentration was significantly higher in bacteria-positive cases than in bacteria-negative cases (p<0.01). ConclusionsIn conclusion, the study data demonstrate the high sensitivity and specificity of the ADA test for the early diagnosis of TBP. In addition, the ADA concentration is directly correlated with the mycobacterial load.

435. Iliopsoas Abscess in Egyptian Patients Presenting to Cairo University Hospitals

BackgroundThe incidence of iliopsoas abscess (IPA) is rare but the frequency of this diagnosis has increased with the use of ultrasonography and computed tomography (CT). The vague presentation leads to delays in diagnosis and increases morbidity. Managing iliopsoas abscess is still forming a therapeutic challenge. The aim of this research was to study the features of iliopsoas abscess cases including the etiology and clinical presentation.MethodsPatients and Methods. all patients presented to the orthopedic outpatient clinic (Cairo university hospitals) by back pain were screened by plain X-ray and IPA was by ultrasonography (US). The confirmed patients were diagnosed as having psoas or iliopsoas collection and subjected to: full history taking, full laboratory workup, screening for tuberculosis, radiological studies and ultrasound-guided needle aspiration of the abscess. The aspirate samples were microbiologically tested by culture (aerobic, anaerobic and MGIT) and PCR technique. Follow-up US was done within 7 days from the first aspiration.ResultsThe outpatient clinic received 40 thousand back pain cases during a one-year study. Only 14 patients were diagnosed as IPA. The age ranged 19–65years (mean 37years) and 57% were male. 44.4% patients had primary IPA while 55.5% patients had secondary IPA. All patients had limping and flank pain, backache or both. Fever was common 90% of patients. Leukocytosis was found in 55.5% of patients, ESR was elevated and CRP was positive in all patients. Z.N stain for AFB was negative in all patients. Culture of aspirated fluid revealed S.aureus as the commonest organism (44% of cultures), then E.coli in (22% of cultures), Mycobacterial tuberculosis in 7% by MGIT culture and PCR. Other cultures were negative. All patients were treated by drainage and appropriate antibiotics. surgical intervention was needed in 22% patients. Recurrence occurred in only 1 patient with tuberculous iliopsoas abscess.ConclusionAlthough IPA is rare, the appropriate diagnosis by US is needed. S.aureus is the commonest pathogen but Mycobacterial tuberculosis could be a cause for recurrence.Disclosures All authors: No reported disclosures.

The Application of Xpert Mycobacterium tuberculosis/Rifampicin, Quantitative Polymerase Chain Reaction and High Resolution Melting Curve in the Diagnosis of Superficial Lymph Node TB.

The diagnostic sensitivity and specificity of conventional methods for superficial lymph node tuberculosis (LNTB) are not ideal. We evaluated several novel methods including Xpert Mycobacterium tuberculosis/rifampicin (Xpert MTB/RIF) technology, quantitative fluorescence Polymerase Chain Reaction (qPCR) and High-Resolution Melting Curve (HRMC) in the diagnosis of superficial lymph node TB. Specimens from eighty-one consecutive patients with suspected LNTB and thirteen cases with other lymph node disease were analyzed by Xpert MTB/RIF, qPCR, and HRMC. Among 81 patients with clinical suspicion of LNTB, there were 74 (91.4%) cases positive Mycobacterium tuberculosis Complex (MTBC) of Xpert MTB/RIF, 60 (74%) positive of qPCR, 24 (29.6%) of positive of BACTEC MGIT960 culture, and 13 (16%) cases positive of Roche culture. 38 cases (46.9%) were diagnosed with LNTB. All test methods showed a diagnostic specificity of 100% for LNTB. The sensitivity of molecular biology techniques was significantly higher than that of the traditional diagnostic methods, and Xpert MTB/RIF was the most sensitive diagnostic assay. On Rifampinresistant detection, Xpert MTB/RIF detected three cases (3.7%) with rpoB gene mutation, and Mycobacterium tuberculosis susceptibility testing detected 2 rifampicin-resistant cases (2.4%) which were consistent with Xpert MTB/RIF results. In the Isoniazid-resistant, 7 cases (8.1) of isoniazid resistance mutations (8.1%) were detected by HNC and 1 case was confirmed by Isoniazid susceptibility test. Molecular detection increased the diagnostic sensitivity of LNTB and improved the detection sensitivity for rifampin and isoniazid resistance strain.

Comparison of GeneXpert and line probe assay for detection of Mycobacterium tuberculosis and rifampicin-mono resistance at the National Tuberculosis Reference Laboratory, Kenya

BackgroundThe dual challenge of low diagnostic sensitivity of microscopy test and technical challenge of performing a TB culture test poses a problem for case detection and initiation of Tuberculosis (TB) second-line treatment. There is thus need for a rapid, reliable and easily accessible assay. This comparative analysis was performed to assess diagnostic performance characteristics of GeneXpert MTB/RIF and Line Probe Assay (LPA).MethodsThree hundred twenty nine sputum samples of patients across the 47 counties in Kenya suspected to have drug resistant TB were picked and subjected to GeneXpert, LPA and Culture MGIT at the National TB Reference Laboratory. Sensitivity, specificity and predictive values were then determined to assess the performance characteristics of the various assays.ResultsAgainst culture MGIT as the gold standard for TB diagnosis, GeneXpert had a sensitivity, specificity, positive predictive value, and negative predictive value of 78.5, 64.9, 59.4 and 82.2% respectively while LPA had 98.4, 66.0, 65.4 and 98.4%. For diagnosis of rifampicin mono-resistance GeneXpert had a moderate agreement (Kappa 0.59, P < 0.01) (sensitivity 62.50%, specificity 96.50%) while LPA that had almost perfect agreement (Kappa = 0.89, p < 0.01) with a (sensitivity 90.0% and specificity 99.1%).ConclusionLPA has a better performance characteristic to GeneXpert and an alternative to culture with regards to detection of RIF’s mono-resistance.

DRUG SENSITIVITY PATTERNS OF TB IN A TERTIARY CARE CENTRE IN MUMBAI

SESSION TITLE: Monday Abstract Posters SESSION TYPE: Original Investigation Posters PRESENTED ON: 10/21/2019 02:30 PM - 03:15 PM PURPOSE: To analyze patterns of drug resistance among Tuberculosis patients in a Tertiary care centre in Mumbai: A Prospective study METHODS: Prospective Descriptive observational study was done over 18 months. A total of 181 Mycobacterium Tuberculosis (MTB) Culture Positive patients were included. DST was done by Bactec MGIT 960. Automated liquid culture systems are recommended by the WHO as the current gold standard for DST. The samples were subjected to DST for the following thirteen drugs with the recommended critical concentrations: Isoniazid, Rifampicin, Pyrazinamide, Ethambutol, Streptomycin, Amikacin, Kanamycin, Capreomycin, Ofloxacin, Moxifloxacin, Ethionamide, Para-aminosalicylic acid, and Clofazimine. A detailed history was taken in the form of a questionnaire which included history, site of TB, past history, antitubercular drugs taken, contact with TB source, previously diagnosed XDR patients were excluded. Sampling was done from pulmonary and extrapulmonary samples for AFB smear and MGIT cultures, and if culture positive DST was done for 13 drugs. The DST results and the patient characteristics were then analyzed. RESULTS: Out of 181 total patients, 83(45.8%) were found to be MDR-TB and 10(5.5%) were XDR-TB. Resistance either to any individual drug or in combination with other drugs was highest for Isoniazid (105, 58.01%), followed by Streptomycin (86, 47.51%), Rifampicin (85, 46.96%), Ethambutol (65, 35.91%), Pyrazinamide (62, 34.25%), Ofloxacin (61, 33.7%), Ethionamide (55, 30.39%), Moxifloxacin (46, 25.41%), Para-aminosalicylic acid (18, 9.94%), Kanamycin (11, 6.08%), Amikacin(10, 5.52%), Capreomycin (10, 5.52%). None of the patients showed resistance to Clofazimine.correlation between XDR-TB and history of previous treatment with anti-TB drugs (p<0.001 by Fischer’s Exact Test). Mean duration of symptoms was 10.5 months for XDR-TB patients as compared to 3.82 months for non XDR-TB patients previously treated cases were significantly higher than new cases among XDR-TB cases compared to non XDR-TB cases. CONCLUSIONS: 1) Out of all drugs, the highest resistance was seen to Isoniazid (58.1%) 2) Ofloxacin resistance (33.7%) was highest among second-line drugs and may be due to inappropriate use of fluoroquinolone as broad-spectrum antibiotics. 3) High resistance to second-line drugs may be due to its widespread and unchecked prescription. 4) Least resistance was seen to second-line aminoglycosides (5.5-6%) 5) No resistance to Clofazimine could probably be due to very little ability of MTB to develop resistance to Clofazimine. CLINICAL IMPLICATIONS: 1. Fluoroquinolones should be used judiciously as shown by our study the highest second-line drug resistance is with fluoroquinolones mostly due to their limitless use as a broad spectrum antibiotic. 2. Isoniazid should not be used with only rifampicin in CP Phase of drug therapy for TB. 3. Clofazimine is a good reserve drug for MDR TB. DISCLOSURES: No relevant relationships by Amita Nene, source=Web Response No relevant relationships by Neel Thakkar, source=Web Response

Comparative evaluation of loop-mediated isothermal amplification (LAMP) assay, GeneXpert MTB/Rif and multiplex PCR for the diagnosis of tubercular lymphadenitis in HIV-infected patients of North India

BackgroundTubercular lymphadenitis (TBLA) is one of the most common extrapulmonary manifestations of tuberculosis in patients with HIV. With several other pathological conditions presenting as lymphadenitis and lack of consensus regarding a gold standard test, the diagnosis of TBLA remains a challenge for the clinician. Objectivesand design: In this study, we have assessed the potential of loop-mediated isothermal amplification (LAMP) test for the diagnosis of TBLA in HIV-infected patients. The study group included samples collected by fine needle aspiration (FNAC) of lymph nodes from 24 HIV-infected patients with TBLA. A composite reference standard was used to identify cases of TBLA based on clinical suspicion, results of cytology, AFB smear, MGIT culture, GeneXpert MTB/RIF, multiplex polymerase chain reaction (MPCR) and subsequently clinical response to antitubercular therapy. These tests were also carried out in 26 control samples of lymph node FNAC from HIV-infected patients with non-tubercular lymphadenitis. ResultsLAMP assay was positive in 19/24 TBLA cases and yielded a sensitivity of 79.17% with 100% specificity. Cytology was suggestive in 18/24 (75%) TBLA cases. GeneXpert MTB/RIF assay correctly identified 16/24 TBLA cases, but the test did show one false positive result reducing its specificity. MPCR had the highest sensitivity of 91.67% as it correctly identified 22/24 cases and showed no false positive result. ConclusionThe current study highlights the potential of LAMP test for the specific diagnosis of tubercular lymphadenitis in FNAC samples from HIV-infected patients, especially when cytology is either non-conclusive or non-available. Though MPCR had a higher sensitivity than LAMP assay, the added advantages of low cost, minimal technical expertise and simplicity of procedure make LAMP assay a suitable diagnostic test in resource-limited settings.

Case Series of Pott’s Spine Diagnosed by ZN Stain and BacTec MGIT in a Tertiary Care Hospital

Introduction: Pott’s spine is a destructive form of tuberculosis and accounts for approximately half of all cases of musculoskeletal tuberculosis. Spinal Tuberculosis is most often missed due to inadequate sample and lack of clinical history. Most of the Extrapulmonary tuberculosis (EPTB) can be diagnosed by Ziehl Nelson stain (ZN) only, when clinically suspected samples are adequate and optimally stained. We are reporting four case series of spinal tuberculosis diagnosed by ZN stain and confirmed by Bactec MGIT Culture.&#x0D; Material &amp; Methods: These four clinically suspected spinal biopsis were received for ZN stain and MTB culture by MGIT.&#x0D; Results: All the four spinal biopsies were found positive by ZN stain as well as by BacTec MGIT.All the four cases were HIV negative. ESR and CRP of all four cases were raised.&#x0D; Discussion &amp; Conclusion: Spinal tuberculosis can be easily diagnosed by ZN stain in resource constraint lab. Despite its common occurrence and the high frequency of long-term morbidity, there are no straight forward guidelines for the diagnosis and treatment of spinal tuberculosis. Early diagnosis and prompt treatment is necessary to prevent permanent neurological disability and to minimize spinal deformity.

Evaluation of modified petroff’s method and manual MGIT culture system to facilitate detection of acid-fast bacilli in smear-negative presumptive cases of pulmonary tuberculosis

Background: Tuberculosis is a major public health problem in India. According to RNTCP guidelines, all efforts are to be made to diagnose tuberculosis on the basis of detection of AFB/ MTB in the clinical specimen; hence all those cases where AFB/ MTB have not been detected are presumptive cases of tuberculosis. In this background, the present study aims to detect AFB/ MTB in the sputum of clinico-radiologically presumptive cases of pulmonary tuberculosis using direct ZN microscopy, Modified Petroff’s method followed by ZN microscopy &amp; MGIT liquid culture method. Materials and Methods: A total of 94 sputum samples which were negative for AFB by direct ZN microscopy at the DMC of the institute, were subjected to Modified Petroff’s method followed by microscopy &amp; MGIT liquid culture test to find out any additional yield of bacteriologically confirmed disease. Result: Out of 94 specimens, 20 (21.28%) were positive for AFB on ZN microscopy post Modified Petroff’s method. Among all the specimens, 30 (31.91%) were found to be positive by MGIT liquid culture method with average time to detection growth (TTD) around 16.73 days (2-38 days). Conclusion: Modified Petroff’s method followed by ZN microscopy &amp; MGIT test for mycobacterial culture can improve case detection.

An improved algorithm for rapid diagnosis of pleural tuberculosis from pleural effusion by combined testing with GeneXpert MTB/RIF and an anti-LAM antibody-based assay

BackgroundThis retrospective study evaluated the performance of a lipoarabinomannan (LAM)-based immunological method for diagnosing pleural tuberculosis (TB) from pleural effusion samples. Results were compared to those obtained using conventional culture and molecular testing methods.MethodsSuspected pleural TB patients who visited Beijing Chest Hospital for medical care between January 2016 and June 2017 were retrospectively analysed in the study. Pleural effusion samples were tested for Mycobacterium tuberculosis (MTB) using the BACTEC MGIT 960 System, GeneXpert, and an anti-LAM antibody assay (LAM assay).ResultsPleural effusion samples were collected from a total of 219 retrospectively recruited participants suspected of having pleural TB. Thirteen of 155 confirmed pleural TB cases tested positive for MTB via MGIT culture, for a sensitivity of 8.4% [95% confidence interval (CI): 4.0–12.8%]. In addition, GeneXpert and LAM testing identified 22 and 55 pleural TB cases, for sensitivities of 14.2% (95% CI: 8.7–19.7%) and 35.5% (95% CI: 28.1–43.6%), respectively. The specificities of these two assays were 100.0% (95% CI: 92.9–100.0%) and 96.9% (95% CI: 88.2–99.5%), respectively. Combined application of culture and LAM testing identified 60 positive cases, for a sensitivity of 38.7% (95% CI: 31.0–46.4%) that was significantly higher than that of MGIT culture alone (P < 0.01). Similarly, use of LAM testing in combination with GeneXpert led to correct diagnosis of 40.0% (95% CI: 32.3–47.7%) of pleural TB cases, a higher rate than obtained using GeneXpert alone (P < 0.01). In addition, the specificity of the combined assay of GeneXpert and LAM testing was 96.9% (95% CI: 88.2–99.5%). Patients aged 25 to 44 years were more likely to have positive LAM assay results than those ≥65 years of age (P = 0.02). Meanwhile, the proportion of diabetic patients with positive LAM assay results was significantly lower than that of the non-diabetes group (P = 0.03).ConclusionsAn anti-LAM antibody detection assay showed potential for diagnosis of pleural TB from pleural effusion samples. Combined use of the LAM assay with MGIT culture or GeneXpert methods could improve sensitivity for improved pleural TB diagnosis compared to results of individual conventional tests alone.

CLINICAL PROFILE, DRUG RESISTANCE PATTERN AND TREATMENT OUTCOMES OF ABDOMINAL TUBERCULOSIS PATIENTS IN WESTERN INDIA.

Abdominal tuberculosis is an increasing problem in developing world. The objective of the study was to describe the clinical presentations, drug resistance pattern and treatment outcomes of abdominal tuberculosis in Western India. All the cases of abdominal tuberculosis from May 2014 to April 2017, diagnosed on the basis of clinical profile and gross morphological findings at endoscopy, imaging, followed by histology and/or GeneXpert and MGIT culture were included. All patients received antitubercular drug (AKT) therapy according to national protocol. Patients were followed from diagnoses till completion of treatment and various parameters were studied. Out of the 176 patients, 48% were males. Abdominal pain was most common complaint in 83.5%. On colonoscopy terminal ileum and ileocaecal valve were most commonly involved segments. Upper gastrointestinal tract was involved in four patients. Overall ulceronodular lesions were most common followed by ulcerative/nodular lesion. Strictures in bowel were seen in 28 (15.9%) patients with ileocaecal valve being most commonly involved, of which 23 had symptomatic relief with AKT and only three required dilatation. Histopathology showed granuloma in 80.8% cases. MGIT was positive in 43 (35.80%) cases and GeneXpert was positive in 35 (26.1%) cases. Eight patients had multi drug resistant tuberculosis. Only two patients required surgical management. Abdominal tuberculosis with wide spectrum of presentation, can still be managed with early diagnosis and treatment even in patients with sub acute intestinal obstruction. Weight gain or resolving symptoms were considered early markers of treatment response. Patients with stricture can become asymptomatic with medical treatment alone.

Diagnosis of paediatric tuberculosis by cartridge based nucleic acid amplification test and its effectiveness as compared to the other conventional diagnostic methods

Background: Childhood TB constitutes 10-20% of all TB cases in high burden countries like India and accounting for 8-20% of TB related deaths. Diagnosis of TB in children is difficult. One test, CBNAAT which was recently endorsed by WHO has the potential to lead a revolution in diagnosis of active TB disease.Methods: A cross sectional study in SCB MCH and SVPPGIP, Cuttack in all the suspected TB patients admitted during the period from January 2016 to October 2017.Results: A total of 100 suspicious patients admitted to the Department of Pediatrics in SCB MCH and SVPPGIP during the study period. Of these 45 were diagnosed TB and rest others were diagnosed otherwise than TB. Diagnosis of TB was established on basis of Microscopy, CBNAAT, culture, biochemistry, cytology, clinical findings, neuroimaging, FNAC/biopsy, USG abdomen. Out of 45 TB patients 30 were CBNAAT positive taking the body fluid samples other than blood, urine and stool with a sensitivity of 66.7% and specificity of 100%. Out of 45 TB patients 14 were having ZN Smear positive taking the same fluid sample with a sensitivity of 31.1% and specificity of 100%. Whereas out of these 45 TB patients 32 were MGIT culture positive taking the same sample with a sensitivity of 71.1% and specificity of 100%. When diagnostic performances of CBNAAT and MGIT culture were compared, it was found to be statistically insignificant with a P value 0.54.Conclusions: The CBNAAT is able to confirm a diagnosis of TB with 66.7% sensitivity and 100% specificity within 2 hours. We can use CBNAAT as a diagnostic method as it provides rapid result and simultaneous better sensitive result, it can be helpful in starting ATT in sick patients and also in outdoor patients.

Retrospective Analysis of False-Positive and Disputed Rifampin Resistance Xpert MTB/RIF Assay Results in Clinical Samples from a Referral Hospital in Hunan, China.

Concerns about the specificity of the Xpert MTB/RIF (Xpert) assay have arisen, as false-positive errors in the determination of Mycobacterium tuberculosis complex (MTBC) infection and rifampin (RIF) resistance in clinical practice have been reported. Here, we investigated 33 cases where patients were determined to be RIF susceptible using the Bactec MGIT 960 (MGIT) culture system but RIF resistant using the Xpert assay. Isolates from two of these patients were found not to have any mutations in the rifampin resistance determining region (RRDR) region of rpoB and had good treatment outcomes with first-line antituberculosis (anti-TB) drugs. The remaining 31 patients included 5 new cases and 26 previously treated patients. A large number of well-documented disputed mutations, including Leu511Pro, Asp516Tyr, His526Asn, His526Leu, His526Cys, and Leu533Pro, were detected, and mutations, including a 508 to 509 deletion and His526Gly, were described here as disputed mutations for the first time. Twenty-one (81%) of the 26 previously treated patients had poor treatment outcomes, and isolates from 19 (90%) of these 21 patients were resistant to isoniazid (INH) as determined using the MGIT culture system. Twenty-seven of the 31 isolates with disputed rpoB mutations were phenotypically resistant to INH, 21 (78%) being predicted by GenoType MTBDRplus to have a high level of INH resistance. Most (77.4%) of the isolates with disputed mutations were of the Beijing lineage. These findings have implications for the interpretation of false-positive and disputed rifampin resistance Xpert MTB/RIF results in clinical samples and provide guidance on how clinicians should manage patients carrying isolates with disputed rpoB mutations.

Estimation of prevalence of multidrug resistance in spinal tuberculosis, antibiotic susceptibility patterns and clinical outcomes

&lt;p class="abstract"&gt;&lt;strong&gt;Background:&lt;/strong&gt; There are no adequate data in literature referring to the early diagnosis and treatment (especially surgical) of MDR tuberculosis of spine and evaluation of its clinical outcome. We aimed to address this lacunae, by using gene expert test (CBNAAT) and drug sensitivity/susceptibility tests (DST) and by studying subsequent actual clinical outcomes.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; Forty patients with clinico-radiological scenario of spinal tuberculosis were evaluated using biochemical, radiological and histo-pathological studies. Anti-tuberculosis treatment was empirically started based on initial clinico-radiological suspicion of spinal tuberculosis. All tissue specimen and intra-operative samples were subjected to CBNAAT, MGIT culture and histopathological examination. Culture of those samples which showed rifampicin resistance on CBNAAT were followed up for DST (Drug Susceptibility Test) and the treatment modified accordingly, if required. All cases were followed up at 3, 6, 9 and 12 months interval.&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results:&lt;/strong&gt; Out of 40 patients, mycobacterium tuberculosis was detected in 23 patients by CBNAAT. Out of these 23 cases, 20 showed mycobacterium tuberculosis sensitivity to rifampicin and 3 were resistant. Out of these 3 cases, one had culture positive. Sensitivity and negative predictive value of gene expert test in comparison with the culture were 100%. Specificity and positive predictive value were calculated at 58.6% and 47.8% respectively. Accuracy of gene expert in our study was found to be 70%.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; Early detection of MDR spinal tuberculosis using highly sensitive CBNAAT test would be helpful to avoid consequences of inappropriate chemotherapy and would result in favourable outcomes.&lt;/p&gt;