Sequential Monotherapy Matches Multidrug Therapy for Mycobacterium avium Lung Infection
Overview
Sequential monotherapy using clarithromycin, bedaquiline, and clofazimine administered in 4-week intervals achieved lung bacterial burden reductions comparable to standard triple-drug therapy in a murine model of Mycobacterium avium lung infection. Importantly, sequential monotherapy did not select for antimicrobial resistance and prevented extrapulmonary dissemination.
Background
Nontuberculous mycobacterial infections, particularly those caused by Mycobacterium avium complex (MAC), are increasing globally and now surpass tuberculosis in incidence in some regions. Current treatment guidelines recommend prolonged multidrug regimens, typically including clarithromycin, ethambutol, and rifampicin, but these are associated with significant toxicity, poor adherence, and low cure rates. Unlike M. tuberculosis, M. avium is environmentally acquired, which may reduce the necessity for simultaneous multidrug therapy to prevent resistance. This study investigates whether sequential monotherapy could be an effective and less toxic alternative.
Data Highlights
Treatment Regimen
Lung Bacterial Burden Reduction
Resistance Emergence
Extrapulmonary Dissemination
Standard triple-drug (clarithromycin + ethambutol + rifampicin)
Sequential monotherapy achieved lung bacterial burden reductions equivalent to standard multidrug therapy in a murine model.
No increase in minimum inhibitory concentrations (MICs) for clarithromycin, bedaquiline, or clofazimine was observed, indicating no selection for resistant clones.
Sequential monotherapy prevented extrapulmonary dissemination of M. avium infection.
Standard multidrug therapy is associated with high toxicity and poor adherence, limiting its effectiveness.
M. avium is environmentally acquired, reducing the public health imperative for simultaneous multidrug therapy to prevent resistance.
Clinical Implications
Sequential monotherapy may offer a viable alternative to current multidrug regimens for M. avium lung disease by maintaining efficacy while potentially reducing toxicity and improving patient adherence. This approach could be particularly beneficial for patients who experience adverse effects or have difficulty tolerating multiple simultaneous antibiotics. Further clinical investigation is warranted to confirm these findings and optimize sequencing strategies.
Conclusion
This proof-of-concept study demonstrates that sequential monotherapy can achieve comparable efficacy to standard multidrug therapy against M. avium lung infection without promoting antimicrobial resistance, supporting further exploration of this treatment strategy as a more tolerable alternative.
References
Griffith et al. 2023 -- Effectiveness of Sequential Monotherapy Approaches for Mycobacterium avium Lung Infection in Murine Models
The expert panel outlines surveillance, device management, and diagnostic stewardship strategies to address both catheter-associated and non–catheter-associated infections.
