From the Guidelines
Treatment for Mycobacterium chelonae in sputum should include a combination of clarithromycin with a second agent, such as tobramycin or amikacin, for at least 12 months after sputum culture conversion to negative, as this approach is likely to be successful based on in vitro susceptibilities 1. The optimal therapy for M. chelonae lung disease is unknown, but a regimen including clarithromycin with a second agent, based on in vitro susceptibilities, would likely be successful 1. Some key points to consider when treating M. chelonae in sputum include:
- The use of clarithromycin (500 mg twice daily) as the cornerstone medication, combined with at least one additional agent based on susceptibility testing 1
- Common second agents include tobramycin, amikacin, imipenem, linezolid, or ciprofloxacin, with tobramycin being more active in vitro than amikacin 1
- Treatment should continue for at least 12 months after sputum culture conversion to negative 1
- Regular monitoring of sputum cultures, liver function, and drug levels is important during treatment
- Side effects of long-term clarithromycin and other antibiotics, such as hearing loss, QT prolongation, nephrotoxicity, and ototoxicity, require close monitoring 1
From the FDA Drug Label
Antimicrobial Activity Clarithromycin has been shown to be active against most of the isolates of the following microorganisms both in vitroand in clinical infections [see Indications and Usage (1)] ... Mycobacterium avium complex (MAC) consisting of M. avium and M intracellulare
The drug label does not mention Mycobacterium chelonae. Mycobacterium avium complex (MAC) is mentioned, but it consists of M. avium and M. intracellulare, not Mycobacterium chelonae. Therefore, the treatment of sputum Mycobacterium chelonae with clarithromycin is not supported by the FDA drug label 2. No conclusion can be drawn about the effectiveness of clarithromycin for this specific indication.
From the Research
Sputum Mycobacterium chelonae Treatment
- Mycobacterium chelonae is a type of rapidly growing mycobacteria that can cause infections in both immunocompromised and immunocompetent patients 3.
- Treatment of M. chelonae infections is challenging due to its resistance to many first-line tuberculosis agents, requiring a long-term multiple drug regimen that can be costly and associated with drug-related toxicities 3.
Antibiotic Susceptibility
- M. chelonae isolates have shown 100% susceptibility to amikacin, clarithromycin, and tobramycin 3.
- No resistance to linezolid, imipenem, and moxifloxacin was observed in M. chelonae isolates 3.
- Ciprofloxacin and doxycycline have shown poor in vitro activity against M. chelonae isolates 3.
- Clarithromycin has been effective in treating M. chelonae infections, but the duration of treatment should be long, especially in immunosuppressed patients 4.
Treatment Options
- A combination of moxifloxacin and clarithromycin has been successfully used to treat cutaneous M. chelonae infections in immunocompromised patients 5.
- Bacteriophage therapy has also been used to treat refractory cutaneous disseminated M. chelonae infections, showing excellent clinical response 6.
- The Etest method has been found to be a simple and reliable method for determining the drug susceptibility of M. chelonae to amikacin, ciprofloxacin, clarithromycin, doxycycline, imipenem, and tobramycin, except for cefoxitin and linezolid 7.
Considerations
- Accurate species determination is critical for treatment, as well as susceptibility status of rapidly growing mycobacteria to antimicrobials in use 3.
- The choice of antibiotics and duration of treatment for nontuberculous mycobacterial infections, including M. chelonae, are not clearly determined and depend on the clinician's experience 5.