Incubation time of Mycobacterium tuberculosis complex sputum cultures in BACTEC MGIT 960: 4weeks of negative culture is enough for physicians to consider alternative diagnoses

Ogwang, Sam; Mubiri, Paul; Bark, Chung Wung; Joloba, Moses; Boom, W. Henry; Johnson, John L.

doi:10.1016/j.diagmicrobio.2015.07.002

Cited by 13 publications

(11 citation statements)

References 8 publications

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“…Baseline TDG is also correlated to time to conversion ( Visser et al, 2012 ) and inversely related to transmissibility ( Khan et al, 2018 ). TDG in treatment-naïve subjects are, as expected, lower in smear positive and NAAT positive subjects ( Khan et al, 2018 ) with median values ranging between 5 ( Bisognin et al, 2020 ; Ma et al, 2020 ) and 23 days ( Boehme et al, 2011 ; Bark et al, 2012 ; Pfyffer and Wittwer, 2012 ; Tyrrell et al, 2012 ; Visser et al, 2012 ; Olaru et al, 2014 ; Ogwang et al, 2015 ; Diriba et al, 2017 ; Khan et al, 2018 ; Zhao et al, 2019 ). A few recent studies suggest that, in the majority of clinical samples, growth of MTB could be detected within 28 days of incubation ( Pfyffer and Wittwer, 2012 ; Ogwang et al, 2015 ).…”

Section: Introductionsupporting

confidence: 72%

“…TDG in treatment-naïve subjects are, as expected, lower in smear positive and NAAT positive subjects ( Khan et al, 2018 ) with median values ranging between 5 ( Bisognin et al, 2020 ; Ma et al, 2020 ) and 23 days ( Boehme et al, 2011 ; Bark et al, 2012 ; Pfyffer and Wittwer, 2012 ; Tyrrell et al, 2012 ; Visser et al, 2012 ; Olaru et al, 2014 ; Ogwang et al, 2015 ; Diriba et al, 2017 ; Khan et al, 2018 ; Zhao et al, 2019 ). A few recent studies suggest that, in the majority of clinical samples, growth of MTB could be detected within 28 days of incubation ( Pfyffer and Wittwer, 2012 ; Ogwang et al, 2015 ). A US multicentric study reported a median TDG of 14 days (using the Mycobacterium Growth Indicator Tube (MGIT) system, Becton Dickinson, Allschwil, Switzerland) with a 100% detection of all positive samples within 28 days, thus suggesting that there was no additional benefit of growing MTB on solid or liquid media for more than 5 weeks ( Tyrrell et al, 2012 ).…”

Section: Introductionsupporting

confidence: 72%

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Time to Detection of Growth for Mycobacterium tuberculosis in a Low Incidence Area

Vongthilath-Moeung

Poncet

Renzi

et al. 2021

Front. Cell. Infect. Microbiol.

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BackgroundDiagnosis of Mycobacterium tuberculosis (MTB) infection can be confirmed by Xpert assays within hours. However, when sample size does not allow performing both culture and Xpert, or if Xpert is negative, then formal diagnosis of MTB relies on culture and time to detection of growth (TDG) becomes critical for clinical management.ObjectivesTo determine TDG in Xpert negative samples, or in samples in which Xpert could not be performed, in a low-incidence area for MTB.MethodsRetrospective analysis (2015-2020) of a database including all cultures for mycobacteria in a University Hospital covering approximately 500’000 inhabitants. Analysis was restricted to culture positive (C+) samples for MTB for which 1/Xpert was negative or could not be performed because of limited sample volume, and 2/collected from subjects treated less than 24 hours. TDG was analyzed according to microscopy, origin of sample (pulmonary or not) and presence of cavitation.ResultsAmong 837 C+ samples for MTB, 236 samples (80% of respiratory origin) from 147 patients fulfilled study criteria; 78 samples (49 patients, 33%) were acid-fast bacilli (AFB) positive. Median (IQR) TDG was 25 (17; 40) days for all samples. TDG exceeded 28 days in 43% of samples and was significantly shorter in AFB+ vs AFB- samples, and samples from cavitary vs non cavitary or extra-thoracic disease.ConclusionsIn Xpert negative samples, or samples for which Xpert could not be performed, TDG exceeded 4 weeks in 43% of samples. AFB+ and samples from cavitary lung disease had a significantly shorter TDG.

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Section: Introductionsupporting

confidence: 72%

Section: Introductionsupporting

confidence: 72%

Time to Detection of Growth for Mycobacterium tuberculosis in a Low Incidence Area

Vongthilath-Moeung

Poncet

Renzi

et al. 2021

Front. Cell. Infect. Microbiol.

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“…Early diagnosis and treatment are essential measures for effectively controlling the epidemic disease [ 1 ]. However, TB detection remains a major obstacle due to several drawbacks of the available diagnostic methods, such as tuberculin skin test [ 2 ], bacteriological culture (e.g., mycobacteria growth indicator tube) [ 3 ], sputum smear microscopy, radiographic methods [ 4 ], and biochemical and nucleic acid amplification methods [ 5 ], among them. To date, the number of diagnosis approaches for TB has increased as the disease continues to be a mayor public health problem worldwide, as a result of the severe threat of multidrug-resistant (MDR) tuberculosis, extensively drug resistant TB (XDR) [ 6 ] and alarming frequency of TB among immunocompromised co-infected patients (e.g., HIV/AIDS) [ 7 ].…”

Section: Introductionmentioning

confidence: 99%

Bioelectrochemical Detection of Mycobacterium tuberculosis ESAT-6 in an Antibody-Based Biomicrosystem

Sepulveda

Aroca

Varela

et al. 2017

Sensors

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Bioelectrochemical sensing of Mycobacterium tuberculosis through electro-immunosensors is a promising technique to detect relevant analytes. In general, immunosensors require the formation of organic assemblies by the adsorption of molecular constituents. Moreover, they depend on the correct immobilization of the bio-recognition element in the biosensor. These procedures cannot be easily monitored without the use of invasive methods. In this work, an impedance analysis technique was used, as a non-invasive method, to measure and differentiate the manufacturing stages of the sensors. Biomicrosystems were fabricated through physical vapor deposition (PVD) of 80 nm Au nanolayers on 35 µm copper surfaces. Later, the surface was modified through thiolation methods generating a self-assembled-monolayer (SAM) with 20 mM 4-aminothiophenol (4-ATP) on which a polyclonal antibody (pAb) was covalently attached. Using impedance analysis, every step of the electro-immunosensor fabrication protocol was characterized using 40 independent replicas. Results showed that, compared to the negative controls, distilled water, and 0.5 µg/mL HSA, a maximum variation of 171% between each replica was achieved when compared to samples containing 0.5 µg/mL of ESAT-6 M. tuberculosis immunodominant protein. Therefore, this development validates a non-invasive method to electrically monitor the assembly process of electro-immunosensors and a tool for its further measure for detection of relevant antigens.

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“…Rapid diagnosis of TB is critical for initiating effective treatment and preventing its transmission in the community [1]. Recent advances in molecular methods have shortened the turnaround time for the identification of Mycobacterium tuberculosis (MTB); however, culture is still essential for phenotypic drug susceptibility testing and improving the case detection of smear negative patients [1, 2]. Due to the slow growth rate, conventional solid culture systems including Löwenstein-Jensen (LJ) slant or Middlebrook 7H11 agar plate always require 8 weeks of incubation before a negative result is reported, which cannot meet the criteria of clinical practice [3].…”

Section: Introductionmentioning

confidence: 99%

“…The culture is monitored with the oxygen-quenching fluorescent sensor technology every 60 minutes, which provides a satisfactory performance in a short laboratory turnaround time when compared with conventional method [2, 4, 5]. The BACTEC MGIT 960 is therefore widely considered as the gold standard for the diagnosis of TB [3].…”

Section: Introductionmentioning

confidence: 99%

Factors Associated with Missed Detection ofMycobacterium tuberculosisby Automated BACTEC MGIT 960 System

Zhang²,

et al. 2016

BioMed Research International

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Despite the demonstration of excellent performance, mycobacterial growth in BACTEC MGIT 960 can go undetected. The aim of this study was to investigate the prevalence of “false-negative” culture sample in Beijing and the potential factors associated with the detection failures by MGIT 960. Of the 577 sputum samples tested, 141 (24.4%) were culture-positive for mycobacteria, of which 133 (94.3%) were automatically determined by MGIT 960 system and 8 (5.7%) were positive for visual growth (false negative by MGIT). Statistical analysis showed that positive grade of specimen had no influence on the false-negative rate by MGIT 960 system (χ 2 = 2.207, P = 0.820). In addition, the mean time to detection (TTD) was 241.4 (range: 224–261) hours for false-negative group and 186.8 (range: 173–199) hours for positive group. The difference in TTD between false-negative and positive groups was statistically significant (P < 0.01). In conclusion, our data demonstrate that the automatic MGIT missed a small portion of bacteriological mycobacterial patients. In addition, the poor growth rate rather than the low grade of AFB smear is associated with the detection failure by MGIT. Our findings highlight the notion that manual inspection for all instrument-negative MGIT tubes will bring about considerable benefit to patients and clinicians.

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Incubation time of Mycobacterium tuberculosis complex sputum cultures in BACTEC MGIT 960: 4weeks of negative culture is enough for physicians to consider alternative diagnoses

Cited by 13 publications

References 8 publications

Time to Detection of Growth for Mycobacterium tuberculosis in a Low Incidence Area

Time to Detection of Growth for Mycobacterium tuberculosis in a Low Incidence Area

Bioelectrochemical Detection of Mycobacterium tuberculosis ESAT-6 in an Antibody-Based Biomicrosystem

Factors Associated with Missed Detection ofMycobacterium tuberculosisby Automated BACTEC MGIT 960 System

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