Implication of species change of Nontuberculous Mycobacteria during or after treatment

Abstract

BackgroundCo-existence or subsequent isolation of multiple nontuberculous mycobacteria (NTM) species in same patient has been reported. However, clinical significance of these observations is unclear. The aim of this study was to determine clinical implications of changes of NTM species during or after treatment in patients with NTM lung disease.MethodsPatients with NTM lung disease, who experienced changes of NTM species during treatment or within 2 years of treatment completion between January 1, 2009 and December 31, 2015, were included in the analysis. Demographic, clinical, microbiological, and radiographic data were reviewed and analyzed.ResultsDuring the study period, 473 patients were newly diagnosed with NTM lung disease. Treatment was started in 164 patients (34.6%). Among these 164 patients, 16 experienced changes of NTM species during or within 2 years of treatment completion. Seven showed changes from M. avium complex (MAC) to M. abscessus subspecies abscessus (MAA) and five patients displayed changes from M. abscessus subspecies massiliense (MAM) to MAC. With isolation of new NTM species, 6 out of 7 patients with change from MAC to MAA reported worsening of symptoms, whereas none of the five patients with change from MAM to MAC reported worsening of symptoms. All MAA isolated during or after treatment for MAC lung diseases showed inducible resistance to clarithromycin.ConclusionsChange of NTM species may occur during or after treatment for NTM lung disease. Especially, changes from MAC to MAA is accompanied by symptomatic and radiographic worsening as well as inducible resistance to clarithromycin.

Nontuberculous Mycobacterial Lung Diseases Caused by Mixed Infection with Mycobacterium avium Complex and Mycobacterium abscessus Complex

“…They are vulnerable to continuous environmental exposure to NTM and are likely to eventually develop NTM lung disease with mixed infection. In addition, there is a possible structural (physical) basis for mixed infections, as species of NTM may differ across ectatic bronchi or nodules, as was speculated in a recent study (26). This phenomenon is in line with previous studies of MAC lung disease, which reported that patients with nodular bronchiectatic forms are repeatedly infected with multiple strains (16,20).…”

“…Similarly, in a study of M. abscessus lung disease in which nearly all (98%) of the study subjects had bronchiectasis and nodular opacities, the prevalence of coexistent or previous MAC infection was as high as 55% (22). In a recent study that evaluated the conversion of NTM species, which included 12 patients with conversion from MAC to MABC or vice versa, all patients had nodular bronchiectasis (26).…”

“…The implications of mixed infection with respect to the clinical outcome of NTM lung disease have not been well studied. Patients with conversion from MAC to M. abscessus lung disease have reported worsening symptoms (26), while development of M. abscessus lung disease during MAC therapy has been associated with the emergence of new or enlarging cavities (17). Likewise, coexisting MAC infection in patients with M. abscessus lung disease has been associated with radiologic progression (25).…”

Clinical and microbiological characteristics of non-tuberculous mycobacteria diseases in Singapore with a focus on pulmonary disease, 2012-2016

“…In this study, around 30% of the pulmonary NTM patients had ≥2 species identified. As clinical treatment data was not gathered in current study, we cannot tell if was related to clinical treatment as suggested by Lee et al [63] However, we found that age ≥ 65 years and COPD were significantly associated with multispecies isolation with OR of 1.7 and 2.2 respectively. Chronic inflammation and remodelling of airways in COPD may play a role in the increased susceptibility to NTM infection.…”

Predictors of developing Mycobacterium kansasii pulmonary disease within 1 year among patients with single isolation in multiple sputum samples: A retrospective, longitudinal, multicentre study

“…In patients receiving treatment for MAC-PD, single respiratory isolation of M. abscessus probably requires no therapy 17 . However, the change from MAC to M. abscessus is usually accompanied by symptomatic and radiographic worsening 24 . Unlike other studies, the present analysis revealed that coexistence of MK and another NTM may be associated with a lower risk of MK-PD and initial high-grade sputum AFS is a risk factor for MK-PD, supporting the hypothesis that quantitative organism load might determine the clinical relevance of NTM-PD 8,11,25 .…”