Evaluation of the BACTEC™ MGIT™ 960 system for the recovery of mycobacteria

Kanchana, M. V.; Cheke, D; Natyshak, I.; Connor, B; Warner, Alexandra N.; Martin, Thomas H.

doi:10.1016/s0732-8893(99)00151-0

Cited by 48 publications

(24 citation statements)

References 8 publications

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“…The median TTD of MTC isolates was 7 days for both methods (Table 2). Although similar TTD values have been reported for MGIT 960 system in other studies (2,5), the design of our study was biased towards slower TTD by the MGIT 960 system and LJ compared to the LRPs. This was due to the fact that sputum sediments were resuspended in 3 ml, a volume larger than that recommended by the Centers for Disease Control and Prevention, and resulted in smaller starting inoculum sizes for MGIT and LJ cultures.…”

Section: Discussionsupporting

confidence: 72%

See 1 more Smart Citation

Luciferase Reporter Mycobacteriophages for Detection, Identification, and Antibiotic Susceptibility Testing of Mycobacterium tuberculosis in Mexico

et al. 2001

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The utility of luciferase reporter mycobacteriophages (LRPs) for detection, identification, and antibiotic susceptibility testing of Mycobacterium tuberculosis was prospectively evaluated in a clinical microbiology laboratory in Mexico City, Mexico. Five hundred twenty-three consecutive sputum samples submitted to the laboratory during a 5-month period were included in this study. These specimens were cultivated in Middlebrook 7H9 (MADC), MGIT, and Löwenstein-Jensen (LJ) media. Of the 71 mycobacterial isolates recovered with any of the three media, 76% were detected with the LRPs, 97% were detected with the MGIT 960 method, and 90% were detected with LJ medium. When contaminated specimens were excluded from the analysis, the LRPs detected 92% ( The microscopic examination of sputum to detect the presence of acid-fast bacilli (AFB) (AFB smear) has served the world well for the past 100 years and is the diagnostic basis of directly observed therapy. However, it fails to identify 30 to 50% of active cases of tuberculosis and cannot identify the increasing numbers of persons diseased by drug-resistant Mycobacterium tuberculosis (7, 10). A reliance solely upon the limited AFB smear is one of the many factors that contribute to poor tuberculosis control in resource-poor countries (1). Although available, conventional mycobacteriological techniques for culture isolation and antibiotic susceptibility testing (AST) are slow, and the more recently developed rapid methods such as the BACTEC and MGIT systems are expensive and require elaborate technology (3, 13, 15). Thus, there is an urgent need for a rapid and affordable method to detect mycobacteria in clinical specimens, to identify whether they are M. tuberculosis, and to determine their antimicrobial susceptibility.Over the past decade, luciferase reporter mycobacteriophages (LRPs) have been developed that show great promise for diagnostic microbiology (4). This novel approach utilizes a genetically engineered reporter phage to detect viable mycobacteria, which upon LRP infection produces quantifiable light. In the presence of antibiotics, bacilli that are drug resistant and retain their viability undergo phage infection and also produce light. In this way, quantification of photons with a luminometer can be used to reveal the susceptibility profile of each isolate. Unlike in the radiometric BACTEC system, the phages do not have any requirement for radioactive isotopes. When mycobacteria are grown in media containing agents such as p-nitro-␣-acetylamino-␤-hydroxypropiophenone (NAP), selective inhibition of M. tuberculosis complex (MTC) organisms allows differentiation from nontuberculous mycobacteria (NTM) (11).To date, the performance of the LRPs for mycobacterial diagnostics has only been tested against a limited number of laboratory strains in a research laboratory (4,12). In this study we prospectively evaluated the diagnostic utility of the LRPs in a centralized diagnostic laboratory in Mexico City, Mexico. We showed (i) that LRP assay can rapidly and sensitively...

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Section: Discussionsupporting

confidence: 72%

“…Cultures were checked for mycobacterial growth on postincubation days 1,3,5,7,11,15,19,23,27, 41, and 55. On each designated day, 80 l of each culture was infected with 8 l of LRP phAE142 in a Falcon 96-well plate (Becton Dickinson Labware, Lincoln Park, N.J).…”

Section: Methodsmentioning

confidence: 99%

Luciferase Reporter Mycobacteriophages for Detection, Identification, and Antibiotic Susceptibility Testing of Mycobacterium tuberculosis in Mexico

et al. 2001

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“…Similar Þ ndings have been reported in the literature. [8][9][10][11][12][13] However in our study, time to detect Mycobacteria by M960 was lesser than that reported by others (11.6-14.4 days). 6,7,8,10,11,13 This is probably because large number of samples (28%) were smear positive and incidence of TB is also higher in our country.…”

Section: Discussionmentioning

confidence: 56%

A comparative study for the detection of mycobacteria by bactec MGIT 960, lowenstein jensen media and direct AFB smear examination

Rishi¹,

Sinha²,

Malhotra³

et al. 2007

Indian J Med Microbiol

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“…For the majority of specimens for AFB culture, modern culture techniques make it possible to meet the 21-day target turnaround time for detection and identification of MTBC as recommended by the Centers for Disease Control and Prevention (22). However, despite standardized techniques for decontamination and concentration and for the addition of antibiotics, contamination of broth cultures by bacteria other than AFB still occurs in 2 to greater than 10% of cultures (8,14,15,18,23,24,26). Many of these contaminated cultures grow AFB as well as other contaminating organisms, thus requiring a redecontamination step and reincubation before the appropriate tests (such as chromatographic or biochemical methods) can be performed for organism identification.…”

mentioning

confidence: 99%

“…The AFB broth culture contamination rates differ among laboratories and depend on factors such as specimen handling, specimen delivery time, processing method, and culture medium used (8,14,15,18,23,24,26). To further identify an organism present in the broth, redecontamination and reincubation (sometimes more than once) are usually required to eliminate non-AFB organisms present in the broth.…”

mentioning

confidence: 99%

Rapid Detection of Mycobacterium tuberculosis in Contaminated BACTEC 12B Broth Cultures by Testing with Amplified Mycobacterium Tuberculosis Direct Test

Zheng

Pang²,

Engler

et al. 2001

J Clin Microbiol

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Contamination of broth cultures of acid-fast bacilli (AFB) by bacterial species other thanMycobacterium species frequently occurs. Many of these contaminated cultures require redecontamination and reincubation before the appropriate tests can be performed for identification, significantly affecting the turnaround time for reporting culture results. In this study, the Amplified Mycobacterium Tuberculosis Direct Test (MTD; GenProbe) was performed to detect the Mycobacterium tuberculosis complex (MTBC) in 125 BACTEC 12B broth cultures with positive growth indices. Among these, 41 grew non-AFB bacteria only, and all 41 were negative by the MTD. The remaining 84 bottles contained contaminated cultures that grew both AFB and other bacteria or yeasts. Repeat decontamination and reincubation of these specimens required a mean time of 13 days (range, 3 to 40 days). The MTD results were positive for 10 samples, 9 of which were MTBC culture positive and 1 of which grew Myobacterium celatum, a species known to cross-react in the MTD. All cultures growing other mycobacterial species were negative by the MTD. The results of this study demonstrate that the MTD is both sensitive and specific in detecting MTBC in contaminated broth cultures and that, when used selectively, the MTD can potentially rule in or out a diagnosis of MTBC as much as 12 days earlier than using nonamplified DNA probe testing alone can.Tuberculosis remains a major cause of morbidity and mortality worldwide. Rapid and accurate detection of the Mycobacterium tuberculosis complex (MTBC) is a key aspect of effective tuberculosis treatment and control. Although the recently introduced nucleic acid amplification tests provide an opportunity for the early diagnosis of disease, routine culture of acid-fast bacilli (AFB) is still necessary for its higher sensitivity and ability to identify mycobacterial species other than MTBC and for the recovery of isolates for antimicrobial susceptibility testing. For the majority of specimens for AFB culture, modern culture techniques make it possible to meet the 21-day target turnaround time for detection and identification of MTBC as recommended by the Centers for Disease Control and Prevention (22). However, despite standardized techniques for decontamination and concentration and for the addition of antibiotics, contamination of broth cultures by bacteria other than AFB still occurs in 2 to greater than 10% of cultures (8,14,15,18,23,24,26). Many of these contaminated cultures grow AFB as well as other contaminating organisms, thus requiring a redecontamination step and reincubation before the appropriate tests (such as chromatographic or biochemical methods) can be performed for organism identification. The turnaround time for reporting culture results is thus significantly affected in this group of cultures. Although the use of DNA probes for detection and identification may be helpful in some of these contaminated cultures, such use is not specified in the manufacturer's instructions or discussed in published literature....

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Evaluation of the BACTEC™ MGIT™ 960 system for the recovery of mycobacteria

Cited by 48 publications

References 8 publications

Luciferase Reporter Mycobacteriophages for Detection, Identification, and Antibiotic Susceptibility Testing of Mycobacterium tuberculosis in Mexico

Luciferase Reporter Mycobacteriophages for Detection, Identification, and Antibiotic Susceptibility Testing of Mycobacterium tuberculosis in Mexico

A comparative study for the detection of mycobacteria by bactec MGIT 960, lowenstein jensen media and direct AFB smear examination

Rapid Detection of Mycobacterium tuberculosis in Contaminated BACTEC 12B Broth Cultures by Testing with Amplified Mycobacterium Tuberculosis Direct Test

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