Reprocessing of Contaminated MGIT 960 Cultures to Improve Availability of Valid Results for Mycobacteria.

Optimal recovery of mycobacteria from the contaminated liquid culture is a challenge. While alternative methods have been suggested to reduce the rate of contamination in the BACTEC MGIT 960 system, reprocessing the contaminated liquid culture improves recovery of . Among 793 MGIT cultures raised from as many sputum specimens after primary decontamination by the standard NaLC-NaOH method, valid results were available for 687 (86.6%) as 106 (13.4%) were contaminated. Reprocessing and reculturing of the contaminated cultures increased valid results to 739 (93.2%) and reduced the contamination rate to 6.8%. Both values were statistically significant. Recovery of the complex increased from 45.6% to 48.4%. Valid negative results were available for an additional 3.4%. The method may be adopted to reduce the rate of contamination and to improve the valid culture results for mycobacteria.