Semiquantitative Culture Analysis during Therapy for Mycobacterium avium Complex Lung Disease

Abstract

Rationale: Microbiologically based criteria such as sputum culture conversion to negative have traditionally been used to define treatment success for mycobacterial diseases. There are, however, limited data regarding whether nontuberculous mycobacterial sputum culture conversion or semiquantitative culture analysis correlates with subjective or nonmicrobiologic objective indices of treatment response.Objectives: To determine whether a semiquantitative mycobacterial culture scale correlated with clinical disease status and was predictive of long-term sputum mycobacterial culture conversion to negative in a cohort of patients with nodular/ bronchiectatic Mycobacterium avium complex lung disease undergoing therapy.Methods: One hundred and eighty patients undergoing standard macrolide-based therapy for M. avium complex lung disease were monitored at standard frequent intervals with symptomatic, radiographic, and microbiologic data collected, including semiquantitative mycobacterial culture analysis. Analyses were used to evaluate clinical and microbiologic predictors of longterm sputum conversion to culture negative.Measurements and Main Results: After 12 months of therapy, 148 (82%) patients had sputum conversion to culture negative. Baseline semiquantitative sputum culture scores did not differ between patients with sputum conversion and those without. The change in sputum culture semiquantitative score from baseline to Month 3 was highly predictive of subsequent sputum long-term conversion status indicative of treatment success, as was improvement in cough, and especially early radiographic improvement.Conclusions: Early semiquantitative sputum agar plate culture results can be used to predict symptomatic and radiographic improvement as well as long-term sputum culture conversion to negative in this population. We suggest that semiquantitative sputum culture scores can be a useful tool for evaluating new nontuberculous mycobacterial lung disease therapies.

Clofazimine-Containing Regimen for the Treatment of Mycobacterium abscessus Lung Disease

“…However, this study demonstrated a significant decrease in the positivity of semiquantitative sputum cultures for AFB over the course of treatment with CFZ in both the initial treatment and salvage treatment groups, suggesting that CFZ-containing regimens can help to decrease the mycobacterial burden. Semiquantitative AFB culture positivity is likely to reflect disease burden and was used to assess microbiological responses to the treatment of NTM lung disease in some recently reported studies (38)(39)(40). Given that M. abscessus lung disease is regarded as a chronic, incurable infection and that there are limited antibiotic options, improvement in the health-related quality of life is a reasonable treatment goal, especially in refractory cases (32).…”

British Thoracic Society guidelines for the management of non-tuberculous mycobacterial pulmonary disease (NTM-PD)

“…While there are no prospective studies indicating which clinical endpoints are most informative during and following treatment for NTM-pulmonary disease, a large retrospective case series involving patients on treatment for MAC-pulmonary disease provides some insights 185. Almost all patients presented with cough, sputum production and fatigue, and patients whose cough improved while prescribed NTM treatment were more likely to culture-convert (p<0.001).…”

When occam's razor can fail– active mycobacteria infection and lung cancer: A case of neuroendocrine lung cancer diagnosed in the setting of refractory mycobacterium avium‐intracellulare

“…For example, an article published in 2015 suggested that changes in a baseline score derived from the semiquantitative measure of MAI growth over a 3‐month period was highly predictive of long‐term sputum conversion and treatment success in pulmonary MAI 7. Regarding pneumonias and other opacities seen on chest imaging of patients at risk for lung cancer, recommendations have suggested follow‐up radiographs or CT scans in 6‐12 weeks post pneumonia treatment to ensure resolution.…”