Sputum smear-positive, culture-negative state during anti-tuberculosis treatment in the MGIT liquid culture era.

The sputum smear-positive, culture-negative state poses a challenge for clinicians. Previous studies have shown that most samples with positive smears during the later stages of treatment are culture-negative. Earlier studies generally used solid culture media, which tend to be less sensitive than current liquid culture systems. We examined the smear-positive, culture-negative state in the era of MGIT™ 960™ liquid cultures. We found that the smear-positive, culture-negative state occurred less frequently with MGIT culture, and that the majority of the samples with late positive smears were culture-negative, regardless of media type.