An integrated approach to detection of Mycobacterium tuberculosis using BD MGIT 320 system and other diagnostic modalities.

  • Gargi Choudhury Department of Microbiology Assam Medical College, Dibrugarh, Assam, India
  • Partha Pratim Das Demonstrator, Department of Microbiology Assam Medical College, Dibrugarh, Assam
  • Lahari Saikia Professor, Department of Microbiology Assam Medical College, Dibrugarh, Assam
Keywords: Liquid culture, Multi drug resistant tuberculosis, extrapulmonary tuberculosis, Line Probe Assay


Background: Application of automated liquid culture system like Becton, Dickinson and Company (BD) MGIT 320 can shorten the recovery time of Mycobacteria in clinical diagnostic laboratories as compared to Lowenstein Jensen (LJ) medium. The present study aimed to compare the results of BD MGIT 320 culture system with that of LJ medium and also to evaluate the usefulness of molecular methods as an adjunct.Methods: Specimen from clinically suspected cases of tuberculosis were processed as per standard guidelines for smear microscopy, solid culture in LJ media, liquid culture in BD MGIT 320 system and Line probe assay. Polymerase chain reaction was performed on extracted DNA from MGIT positive specimen to detect IS6110 and MPB64 gene targets.Result: Out of total 83 specimens, a statistically significant higher isolation rate (25.3%, n=21) was shown by MGIT 320 system in comparison to LJ medium (12.04%, n=10). Line Probe Assay was positive in 37.3% (n=31) and direct microscopy was positive in only 13.25% (n=11) specimen. The average duration of detection was found to be more rapid by MGIT320 than LJ culture (18 days vs 24.1 days). Among the 21 MGIT positive specimens 7 were found positive for both IS6110 and MPB64 gene while 7 specimens were found positive only for IS6110.Conclusion: The automated liquid culture systems like BD MGIT 320 have a higher isolation rate and are more rapid as compared to solid media. But adoption of Line probe assay combined with MGIT culture will definitely yield rapid and efficient detection of Mycobacteria. DOI: 10.21276/AABS.1736

Author Biographies

Gargi Choudhury, Department of Microbiology Assam Medical College, Dibrugarh, Assam, India
Assistant Professor, Department of Microbiology
Partha Pratim Das, Demonstrator, Department of Microbiology Assam Medical College, Dibrugarh, Assam
Demonstrator, Department of Microbiology
Lahari Saikia, Professor, Department of Microbiology Assam Medical College, Dibrugarh, Assam
Professor, Department of Microbiology


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