Mycobacterium Chelonae Treatment & Management

Updated: Jun 07, 2022
  • Author: Mary B Ford, MD; Chief Editor: Michael Stuart Bronze, MD  more...
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Treatment

Medical Care

There are no guidelines outlining optimal treatment for M chelonae infections, and recommendations are based on expert consensus and experience. Antimicrobial therapy is the mainstay of treatment for M chelonae disease when eradication via surgical intervention cannot be accomplished. It is critical to differentiate M chelonae from the closely related M abscessus when attempting treatment, as therapy for M chelonae has key differences from M abscessus due to fewer antimicrobial resistance patterns. [8]  General principles for treatment of disease secondary to M chelonae are similar to treatment of other NTM – therapy typically is prolonged and requires multiple agents that only are chosen after drug susceptibility testing is performed. chelonae isolates do not contain an erm gene, so they typically are considered fully susceptible to macrolides. This results in macrolides being the backbone of M chelonae therapy. [45]

Although much of the data for M chelonae treatment is with clarithromycin, azithromycin does have some advantages including better tolerability and less severe drug interactions. [46]  It is critical to note that macrolide resistance can develop rapidly when monotherapy is used, thus combination therapy is vital. [47]  Additional agents typically are aminoglycosides (tobramycin has more in vitro activity against M chelonae than amikacin), linezolid, clofazimine, and occasionally imipenem, fluoroquinolones, and tetracyclines. [8, 45]  M chelonae have elevated MICs (>128) to cefoxitin, and are considered uniformly resistant. [5]  As therapy recommendations can differ based upon the clinical syndrome, treatment for the most common syndromes is discussed separately.

Pulmonary disease:

Treatment of M chelonae initially was addressed by the ATS/IDSA 2007 treatment guidelines for NTM-PD. Recommendations at that time were to utilize in vitro susceptibilities and to treat with clarithromycin and a second susceptible agent for at least 12 months after negative sputum cultures were obtained. [8]  Neither the 2020 updated guidelines nor the 2017 management guideline by the British Thoracic Society cover pulmonary disease caused by M chelonae. In 2022, Lange et al published a statement with consensus management recommendations for less common NTM-PD. [39, 45]  Based upon their review of documented cases of M chelonae pulmonary disease, they recommend for mild to moderate disease to start with at least 2 susceptible drugs. For more severe disease, they recommend that 3 drugs should be used, typically with 1 or 2 intravenous drugs for the first 4 to 16 weeks. [45]  Given predictable macrolide susceptibility, at least 2 oral drugs, with 1 of those being a macrolide, should be administered for at least 12 months after respiratory cultures convert to culture negative. [45]

Skin, Soft Tissue, and Bone Disease:

Although monotherapy with macrolides (particularly clarithromycin) was considered acceptable, more recent data have shown concern for the development of resistance with macrolide monotherapy. [47, 48]  As such, medical treatment of extensive skin and soft tissue infections typically consists of combination therapy (2 to 3 agents) for a minimum of 4 months pending clinical improvement, whereas bone infections require at least 6 months. [8]  Similar to pulmonary disease, parenteral therapy typically is continued for the first 2-4 weeks of treatment, which can be followed by oral medications for the duration of therapy. [6]  For minor or localized disease, it may be appropriate to treat with only oral medications. [6]

Disseminated disease:

Recommendations for treatment of disseminated disease come from expert consensus based on clinical experience. A parenteral agent in combination with a macrolide in the initial phase of treatment, for a total of 2 to 3 antimicrobials, is recommended, with a duration of at least 6 months. [9]  Tobramycin and imipenem (both parenteral) typically are given for the first 2 to 6 weeks in combination with a macrolide. [5]

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Surgical Care

Surgical resection for pulmonary disease is not well studied in patients with M chelonae, but may be considered in patients who have localized lung disease, fail antimicrobial therapy, or have severe complications such as hemoptysis. [9]  A review of documented cases revealed that approximately 20% of patients with M chelonae pulmonary disease required partial pulmonary surgical resection in addition to antimicrobials, typically with a successful treatment course. [45]

It generally is accepted that surgical excision of localized disease can be curative. Surgery may be necessary in the case of abscess formation requiring drainage or with particularly drug resistant organisms. [5, 46]  Disseminated skin or soft tissue disease often occurs in patients who are immunosuppressed and unable to control their disease even with antimicrobials, at which point surgical debridement may be necessary. [9]  It also is critical to remove any foreign bodies associated with the infection, including catheters, biomaterial associated with ocular surgery, prosthetic joints, and breast implants or other implanted devices. [8, 25]

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Consultations

In general, a consultation with an infectious disease specialist to help guide diagnostic and therapeutic decisions is appropriate. Additional expert guidance can be obtained from several centers around the country including the National Institutes of Health in Bethesda, Maryland; National Jewish Health in Denver, Colorado; and The University of Texas Health Science Center at Tyler in Tyler, Texas – all of which have NTM experts on staff.

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Prevention

There are no specific recommendations for prevention of infection with M chelonae, as these organisms are ubiquitous and community acquired disease has been reported worldwide. [6]  Note that M chelonae is not a communicable disease, and no specific isolation precautions are required. Experts have suggested that patients with possible or definite NTM disease be adequately evaluated and treated before initiation of anti-TNF-alpha therapy because of the potential risk for disease progression. [49]  Given the known association of M chelonae infection with immunosuppression, it is reasonable to suggest that if an NTM infection is suspected or diagnosed, treatment should be considered before initiation of any immunosuppressive treatments. [21]

Prevention of health-care associated NTM outbreaks and pseudo-outbreaks is addressed in the 2007 ATS/IDSA NTM guidelines. The overarching theme of this guidance is to avoid contact between tap water and invasive devices (intravenous catheters, fiberoptic endoscopes, and surgical instruments), as tap water often can serve as a reservoir for NTM. [8]  Additionally, it is critical that any potential health-care associated outbreaks or pseudo-outbreaks are recognized and reported to hospital infection control to prevent further transmission. [8]

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Long-Term Monitoring

The need for long-term monitoring should be determined on a case-by-case basis with evaluation of patient’s clinical syndrome and treatment plan.

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Inpatient & Outpatient Medications

If parenteral therapy is to be initiated, patients often will be admitted for the placement of a long-term central venous catheter to facilitate outpatient parenteral antibiotic therapy. There is no specific recommendation for inpatient versus outpatient treatment. 

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