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.

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 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.

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.

scholarly journals Isoniazid Resistance in Mycobacterium tuberculosis Is a Heterogeneous Phenotype Composed of Overlapping MIC Distributions with Different Underlying Resistance Mechanisms

2019 ◽  
Vol 63 (7) ◽  
Author(s):  
Arash Ghodousi ◽  
Elisa Tagliani ◽  
Eranga Karunaratne ◽  
Stefan Niemann ◽  
Jennifer Perera ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Resistance Mechanisms ◽  
Whole Genome ◽  
Tube System ◽  
Isoniazid Resistance ◽  
Content Type ◽  
Indicator Tube ◽  
Promoter Mutations ◽  
Level Resistance ◽  
Growth Indicator

ABSTRACT MIC testing using the Bactec mycobacteria growth indicator tube system 960 of 70 phylogenetically diverse, isoniazid-resistant clinical strains of Mycobacterium tuberculosis revealed a complex pattern of overlapping MIC distributions. Whole-genome sequencing explained most of the levels of resistance observed. The MIC distribution of strains with only inhA promoter mutations was split by the current concentration endorsed by the Clinical and Laboratory Standards Institute to detect low-level resistance to isoniazid and is, consequently, likely not optimally set.

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 Time to Detection of Mycobacterium tuberculosis Using the MGIT 320 System Correlates with Colony Counting in Preclinical Testing of New Vaccines

2013 ◽  
Vol 21 (3) ◽  
pp. 453-455 ◽  
Author(s):  
K. Kolibab ◽  
A. Yang ◽  
M. Parra ◽  
S. C. Derrick ◽  
S. L. Morris
Keyword(s):  
Culture System ◽  
Liquid Culture ◽  
Preclinical Testing ◽  
Content Type ◽  
Solid Media ◽  
Liquid Culture System ◽  
Colony Counting ◽  
Liquid Systems ◽  
Time To Detection ◽  
New Vaccines

ABSTRACTClinical studies have suggested that the enumeration of mycobacteria by using automated liquid systems is a faster and simpler alternative to quantitative cultures. Here, we show that the time to detection ofM. tuberculosisgrowth as measured with the MGIT 320 liquid culture system inversely correlates with CFU determinations from culture on solid media and that mycobacterial quantification using the MGIT system is faster and easier to perform than CFU plating.

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