scholarly journals Evaluation of OMNIgene Sputum and Ethanol Reagent for Preservation of Sputum Prior to Xpert and Culture Testing in Uganda

2019 ◽  
Vol 58 (1) ◽  
Author(s):  
Elisa Ardizzoni ◽  
Patrick Orikiriza ◽  
Charles Ssuuna ◽  
Dan Nyehangane ◽  
Mourad Gumsboga ◽  
...  
Keyword(s):  
Newly Diagnosed ◽  
Time Points ◽  
Indicator Tube ◽  
Lower Detection ◽  
Tuberculosis Diagnosis ◽  
Mycobacterial Growth ◽  
Pooled Samples ◽  
Reliable Methods ◽  
Mycobacterial Growth Indicator Tube ◽  
Growth Indicator

ABSTRACT Xpert MTB/RIF (Xpert) and culture are the most reliable methods for tuberculosis diagnosis but are still poorly accessible in many low-resource countries. We aimed to assess the effects of OMNIgene Sputum (OM-S) and ethanol in preserving sputum for Xpert and OM-S for mycobacterial growth indicator tube (MGIT) testing over periods of 15 and 8 days, respectively. Sputum samples were collected from newly diagnosed smear-positive patients. For Xpert, pooled samples were split into 5 aliquots: 3 for Xpert on days 0, 7, and 15 without additive and 2 with either OM-S or ethanol at day 15. For MGIT, 2 aliquots were tested without preservative and 2 with OM-S at 0 and 8 days. Totals of 48 and 47 samples were included in the analysis for Xpert and culture. With Xpert, using day 0 as a reference, untreated samples stored for 7 and 15 days showed concordances of 45/46 (97.8%) and 46/48 (95.8%). For samples preserved with OM-S or ethanol for 15 days compared with untreated samples processed at day 0 or after 15 days, OM-S concordances were 46/48 (95.8%) and 47/48 (97.9%), while those of ethanol were 44/48 (91.7%) and 45/48 (93.8%). With MGIT, concordances between untreated and OM-S-treated samples were 21/41 (51.2%) at day 0 and 21/44 (47.7%) at day 8. In conclusion, Xpert equally detected tuberculosis in OM-S-treated and untreated samples up to 15 days but showed slightly lower detection in ethanol-treated samples. Among OM-S-treated samples, MGIT positivity was significantly lower than in untreated samples at both time points.

scholarly journals Accuracy of Xpert Ultra in Diagnosis of Pulmonary Tuberculosis among Children in Uganda: a Substudy from the SHINE Trial

2020 ◽  
Vol 58 (9) ◽  
Author(s):  
Willy Ssengooba ◽  
Jean de Dieu Iragena ◽  
Lydia Nakiyingi ◽  
Serestine Mujumbi ◽  
Eric Wobudeya ◽  
...  
Keyword(s):  
Positive Result ◽  
Diagnostic Challenge ◽  
Indicator Tube ◽  
Lowenstein Jensen ◽  
Mgit Culture ◽  
Mycobacterial Growth ◽  
Culture Positive ◽  
Mycobacterial Growth Indicator Tube ◽  
Higher Sensitivity ◽  
Growth Indicator

ABSTRACT Childhood tuberculosis (TB) presents significant diagnostic challenges associated with paucibacillary disease and requires a more sensitive test. We evaluated the diagnostic accuracy of Xpert MTB/RIF Ultra (Ultra) compared to other microbiological tests using respiratory samples from Ugandan children in the SHINE trial. SHINE is a randomized trial evaluating shorter treatment in 1,204 children with minimal TB disease in Africa and India. Among 352 samples and one cervical lymph node fine needle aspirate, one sample was randomly selected per patient and tested with the Xpert MTB/RIF assay (Xpert) and with Lowenstein-Jensen medium (LJ) and liquid mycobacterial growth indicator tube (MGIT) cultures. We selected only uncontaminated stored sample pellets for Ultra testing. We estimated the sensitivity of Xpert and Ultra against culture and a composite microbiological reference standard (any positive result). Of 398 children, 353 (89%) had culture, Xpert, and Ultra results. The median age was 2.8 years (interquartile range [IQR], 1.3 to 5.3); 8.5% (30/353) were HIV infected, and 54.4% (192/353) were male. Of the 353, 31 (9%) were positive by LJ and/or MGIT culture, 36 (10%) by Ultra, and 16 (5%) by Xpert. Sensitivities (95% confidence intervals [CI]) were 58% (39 to 65% [18/31]) for Ultra and 45% (27 to 64% [14/31]) for Xpert against any culture-positive result, with false positives of <1% and 5.5% for Xpert and Ultra. Against a composite microbiological reference, sensitivities were 72% (58 to 84% [36/50]) for Ultra and 32% (20 to 47% [16/50]) for Xpert. However, there were 17 samples that were positive only with Ultra (majority trace). Among children screened for minimal TB in Uganda, Ultra has higher sensitivity than Xpert. This represents an important advance for a condition which has posed a diagnostic challenge for decades.

Evaluation of the BBL MGIT (Mycobacterial Growth Indicator Tube) AST SIRE System for Antimycobacterial Susceptibility Testing of Mycobacterium tuberculosis to 4 Primary Antituberculous Drugs

2000 ◽  
Vol 124 (1) ◽  
pp. 82-86
Author(s):  
John S. Bergmann ◽  
Geoffrey Fish ◽  
Gail L. Woods
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Susceptibility Testing ◽  
Clinical Isolates ◽  
Indicator Tube ◽  
The Mean ◽  
Inoculum Preparation ◽  
Mycobacterial Growth ◽  
Mean Time ◽  
Mycobacterial Growth Indicator Tube ◽  
Growth Indicator

Abstract Objective.—To evaluate the performance of the BBL MGIT (Mycobacterial Growth Indicator Tube) AST SIRE system for the antimycobacterial susceptibility testing of Mycobacterium tuberculosis to isoniazid (at a concentration equivalent to the lower concentration used for testing by the method of proportion), rifampin, ethambutol, and streptomycin. Design.—Thirty-one clinical isolates and 30 challenge strains provided by the Centers for Disease Control and Prevention (CDC) were tested by MGIT AST SIRE using 2 methods of inoculum preparation, and results were compared with those of the method of proportion, which was considered the reference method. Clinical isolates for which the results of the 2 methods were discordant also were tested at 2 reference laboratories. Results.—Based on data from our site and the reference laboratories, agreement rates between initial MGIT AST SIRE results and the method of proportion for the clinical isolates with the inoculum prepared from a McFarland equivalent and from a positive MGIT tube, respectively, were 100% and 96.8% for isoniazid, 100% and 100% for rifampin, 96.8% and 100% for ethambutol, and 100% and 100% for streptomycin, excluding the isolate for which the discordant streptomycin result could not be resolved. For the 30 challenge isolates, agreement rates between MGIT AST SIRE and expected results and between method of proportion and expected results, respectively, were 96.7% and 93.3% for isoniazid, 93.3% and 100% for rifampin, 83.3% and 100% for ethambutol, and 93.3% and 100% for streptomycin. For the clinical isolates, the mean time to an MGIT AST SIRE result of susceptible was 6.15 ± 0.13 days (range, 5–8 days). For a result of resistant, the mean time overall was 5.00 ± 0.24 days (range, 3–8 days). Conclusion.—These data suggest that the MGIT AST SIRE system, using either method of inoculum preparation, is an acceptable alternative to the BACTEC 460 TB method of susceptibility testing of clinical isolates of M tuberculosis to isoniazid, rifampin, ethambutol, and streptomycin. Reasons for the lower agreement with the CDC challenge isolates should be investigated. Further evaluation of the MGIT AST SIRE system using a concentration of isoniazid equivalent to the higher concentration tested by the method of proportion would be useful, because the decision concerning use of this agent generally is based on the susceptibility test result at the higher concentration.

scholarly journals Comparison of MGIT and Myco/F Lytic Liquid-Based Blood Culture Systems for Recovery of Mycobacterium tuberculosis from Pleural Fluid

2015 ◽  
Vol 53 (4) ◽  
pp. 1391-1394 ◽  
Author(s):  
Elizabeth Harausz ◽  
John Kafuluma Lusiba ◽  
Mary Nsereko ◽  
John L. Johnson ◽  
Zahra Toossi ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Pleural Fluid ◽  
Culture System ◽  
Liquid Culture ◽  
Content Type ◽  
Indicator Tube ◽  
Liquid Culture System ◽  
Mycobacterial Growth ◽  
Mycobacterial Growth Indicator Tube ◽  
Growth Indicator

The specificities and sensitivities of the Bactec mycobacterial growth indicator tube (MGIT) system for the recovery ofMycobacterium tuberculosisfrom pleural fluid are not statistically different than those of the Myco/F lytic liquid culture system. The time to positivity is shorter in the MGIT system (12.7 versus 20.7 days, respectively;P= 0.007). The Myco/F lytic culture system may be an alternative to the MGIT system for diagnosing pleural tuberculosis.

scholarly journals Comparison of Mycobacterial Growth Indicator Tube with Culture on RGM Selective Agar for Detection of Mycobacteria in Sputum Samples from Patients with Cystic Fibrosis

2016 ◽  
Vol 54 (8) ◽  
pp. 2047-2050 ◽  
Author(s):  
Ian Eltringham ◽  
Julie Pickering ◽  
Helen Gough ◽  
Clair L. Preece ◽  
John D. Perry
Keyword(s):  
Cystic Fibrosis ◽  
Culture Medium ◽  
Culture Method ◽  
Culture Methods ◽  
College Hospital ◽  
Indicator Tube ◽  
King's College ◽  
Mycobacterial Growth ◽  
Mycobacterial Growth Indicator Tube ◽  
Growth Indicator

Nontuberculous mycobacteria (NTM) are an important cause of pulmonary disease in patients with cystic fibrosis (CF). A new culture medium (RGM medium) for the isolation of rapidly growing mycobacteria from the sputum of cystic fibrosis patients has recently been reported. The aim of this study was to compare culture of sputum samples on RGM medium with culture using a standard automated liquid culture method. Sputum samples were obtained from 187 distinct patients with CF attending King's College Hospital, London, United Kingdom. Each sample was decontaminated with 3% oxalic acid and inoculated into a mycobacterial growth indicator tube (MGIT) that was monitored for 42 days using the Bactec MGIT 960 instrument. Each sample was also cultured, without decontamination, onto RGM medium, which was incubated for 10 days at 30°C. Mycobacteria were isolated from 28 patients (prevalence, 15%). Mycobacteria were detected in 24 samples (86%) using the MGIT and in 23 samples (82%) using RGM medium (P= 1.00). In this setting, RGM medium showed sensitivity equivalent to that of the MGIT for isolation of NTM from the sputum of patients with CF. RGM medium offers a simple, convenient tool that can be embedded into routine culture methods, allowing the culture of all sputum samples that are submitted from patients with CF.

scholarly journals Improving diagnosis and monitoring of treatment response in pulmonary tuberculosis using the molecular bacterial load assay (MBLA)

2019 ◽  
Author(s):  
Wilber Sabiiti ◽  
Khalide Azam ◽  
Davis Kuchaka ◽  
Bariki Mtafya ◽  
Ruth Bowness ◽  
...  
Keyword(s):  
Pulmonary Tuberculosis ◽  
Health Care Professionals ◽  
Bacterial Load ◽  
Treatment Monitoring ◽  
Viable Count ◽  
Similar Time ◽  
Indicator Tube ◽  
Mycobacterial Growth ◽  
Mycobacterial Growth Indicator Tube ◽  
Growth Indicator

AbstractObjectivesBetter outcomes in tuberculosis require new diagnostic and treatment monitoring tools. In this paper we evaluated the utility of a marker ofM. tuberculosisviable count, the Molecular Bacterial Load assay (MBLA) for diagnosis and treatment monitoring of tuberculosis in a high burden setting.MethodsPatients with smear positive pulmonary tuberculosis from two sites in Tanzania and one each in Malawi and Mozambique. Sputum samples were taken weekly for the first 12 weeks of treatment and evaluated by MBLA and mycobacterial growth indicator tube method (MGIT).ResultsThe results of high and low positive control samples confirmed inter site reproducibility. Over the 12 weeks of treatment there was a steady decline in the viable bacterial load as measured by the MBLA that corresponds to rise in time to a positive result (TTP) in the Mycobacterial Growth Indicator Tube. Both MBLA and MGIT provided similar time to test negativity. Importantly, as treatment progressed samples in MGIT were increasingly likely to be contaminated, which compromised the acquisition of results but did not affect MBLA samples.ConclusionsMBLA produces a reproducible measure ofMtbviable count comparable to that of MGIT that is not compromised by contamination in a real-world setting. As a molecular test, the results can be available in as little as four hours and could allow health care professionals to identify rapidly patients who are failing therapy.

scholarly journals IP-MS Analysis of ESX-5 and ESX-1 Substrates Enables Mycobacterial Species Identification

2020 ◽  
Author(s):  
Qingbo Shu ◽  
Meena Rajagopal ◽  
Jia Fan ◽  
Lingpeng Zhan ◽  
Xiangxing Kong ◽  
...  
Keyword(s):  
Clinical Samples ◽  
Mycobacterial Species ◽  
The Past ◽  
Indicator Tube ◽  
Mgit Culture ◽  
Species Specific ◽  
Mycobacterial Growth ◽  
Slow Growing ◽  
Mycobacterial Growth Indicator Tube ◽  
Growth Indicator

AbstractPulmonary disease resulting from non-tuberculous mycobacteria (NTM) infection has emerged as an increasingly prevalent clinical entity in the past two to three decades, but there are no standardized, commercial assays available for the molecular diagnosis of NTM infections from clinical samples. Herein we discuss the development of an assay that employs immunoprecipitation coupled with mass spectrometry (IP-MS) to rapidly and accurately discriminate prevalent slow-growing mycobacterial species (i.e., M. avium and M. intracellulare, M. kansasii, M. gordonae, M. marinum and M. tuberculosis) during early growth in mycobacterial growth indicator tube (MGIT) cultures. This IP-MS assay employs antibodies specific for conserved tryptic peptides of M. tuberculosis EsxN (AQAASLEAEHQAIVR) and CFP-10 (TQIDQVESTAGSLQGQWR) to capture and identify specific mycobacterial species and allows species-specific mycobacterium identification at the first sign of MGIT culture positivity.

scholarly journals Molecular Bacterial Load Assay Concurs with Culture on NaOH-Induced Loss ofMycobacterium tuberculosisViability

2019 ◽  
Vol 57 (7) ◽  
Author(s):  
Bariki Mtafya ◽  
Wilber Sabiiti ◽  
Issa Sabi ◽  
Joseph John ◽  
Emanuel Sichone ◽  
...  
Keyword(s):  
Bacterial Load ◽  
Viable Count ◽  
Response Monitoring ◽  
The Novel ◽  
Content Type ◽  
Indicator Tube ◽  
Naoh Treatment ◽  
Mycobacterial Growth ◽  
Mycobacterial Growth Indicator Tube ◽  
Growth Indicator

ABSTRACTEffective methods to detect viableMycobacterium tuberculosis, the main causative agent of tuberculosis (TB), are urgently needed. To date, cultivation ofM. tuberculosisis the gold standard, which depends on initial sample processing withN-acetyl-l-cysteine–sodium hydroxide (NALC-NaOH), chemicals that compromiseM. tuberculosisviability and, consequently, the performance of downstream tests. We applied culture and the novel molecular bacterial load assay (MBLA) to measure the loss ofM. tuberculosisviability following NALC-NaOH treatment ofM. tuberculosisH37Rv pure culture and clinical sputum samples from pulmonary TB patients. Compared to the bacterial loads of untreated controls, NALC-NaOH treatment ofM. tuberculosisreduced the MBLA-detectable bacillary load (estimated number of CFU [eCFU] per milliliter) by 0.66 ± 0.21 log10at 23°C (P = 0.018) and 0.72 ± 0.08 log10at 30°C (P = 0.013). Likewise, NALC-NaOH treatment reduced the viable count on solid culture by 0.84 ± 0.02 log10CFU/ml at 23°C (P < 0.001) and 0.85 ± 0.01 log10CFU/ml at 30°C (P < 0.001), respectively. The reduction in the viable count was reflected by a corresponding increase in the time to positivity of the mycobacterial growth indicator tube (MGIT) liquid culture: 1.2 days at 23°C (P < 0.001) and 1.1 days at 30°C (P < 0.001). This NaOH-inducedM. tuberculosisviability loss was replicated in clinical sputum samples, with the bacterial load dropping by 0.65 ± 0.17 log10from 5.36 ± 0.24 log10eCFU/ml to 4.71 ± 0.16 log10eCFU/ml for untreated and treated sputa, respectively. Applying the model of Bowness et al. (R. Bowness, M. J. Boeree, R. Aarnoutse, R. Dawson, et al., J Antimicrob Chemother 70:448–455, 2015,https://doi.org/10.1093/jac/dku415) revealed that the treated MGIT time to culture positivity of 142 ± 7.02 h was equivalent to 4.86 ± 0.28 log10CFU, consistent with the MBLA-measured bacterial load. Our study confirms the contribution of NALC-NaOH treatment to the loss of viable bacterial counts. Tests that obviate the need for decontamination may offer an alternative option for the accurate detection of viableM. tuberculosisand treatment response monitoring.

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