Compared with culture on Lowenstein-Jensen solid medium, the principal advantage of the BACTEC MGIT 960 liquid culture system for recovery of M. tuberculosis is:
- A Ability to differentiate M. tuberculosis from nontuberculous mycobacteria automatically
- B Elimination of the need for biosafety level 3 facilities
- C Detection of growth in approximately 10 to 14 days instead of 3 to 6 weeks ✓
- D Higher specificity with fewer contaminated cultures
Explanation
MGIT tubes contain a fluorescent compound quenched by dissolved oxygen; multiplying bacilli consume oxygen, fluorescence increases, and the instrument flags positivity, typically in 10 to 14 days versus 3 to 6 weeks on egg-based solid medium. Liquid systems actually carry a higher contamination rate than LJ, so specificity is not improved, and speciation still requires separate identification steps such as MPT64 testing or NAAT. Biosafety requirements remain stringent because cultures amplify viable bacilli regardless of the system used.
Reference: Mandell, Douglas and Bennett's Principles and Practice of Infectious Diseases, 9th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.