RT Journal Article SR Electronic T1 The value of semi-quantitative mycobacterial cultures for predicting culture conversion during MAC lung disease therapy JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP P246 VO 44 IS Suppl 58 A1 David Griffith A1 Jennifer Adjemian A1 Barbara Brown-Elliott A1 Julie Philley A1 D. Rebecca Prevots A1 Sally Hunsberger A1 Christopher Gaston A1 Kenneth Olivier A1 Richard Wallace YR 2014 UL http://erj.ersjournals.com/content/44/Suppl_58/P246.abstract AB Background: The key measure of treatment success for Mycobacterium avium complex (MAC) lung disease is conversion of sputum mycobacterial cultures. Decreasing semi-quantitative mycobacterial culture scores have been interpreted, though not systematically evaluated, as predictive of culture conversion.Methods: Mycobacterial cultures obtained every 1-2 months for 12 months from MAC lung disease patients on therapy were evaluated with a semi-quantitative ordinal score; 0=no growth, 1=liquid media growth only; 2= <50 colonies on solid media; 3-6=1+ to 4+ growth on solid media. We performed logistic regression on culture data to evaluate the predictive value of early changes in culture scores for culture conversion by 12 months.Results: We evaluated 180 MAC lung disease patients on therapy with mean of 13.3±7.7 cultures collected/patient. For each unit decrease in the 2nd culture result (median= 35 days from baseline culture), for each unit change in the 3rd culture result (median= 36 days from culture 2) and for each unit change in the 4th culture result (median= 113 days from culture 3), patients were, respectively 40% (p=0.002), 2 (p<0.001) and 5 times (p<0.001) more likely to have culture conversion. For each unit change in the difference between the baseline and 2nd cultures, and for each unit change in the difference between the baseline and 3rd cultures, patients were 9.5 (CI 4.3-21.1) and 12.1 (CI 4.8-30.3) times, respectively, more likely to have culture conversion.Conclusions: Early decreases in semi-quantitative culture scores are predictive of mycobacterial culture conversion for patients on therapy for MAC lung disease.