Treatment outcome definitions in nontuberculous mycobacterial pulmonary disease: an NTM-NET consensus statement

Pharmacotherapy for nontuberculous mycobacterial pulmonary disease

DISCLAIMER

In an effort to expedite the publication of articles , AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.

PURPOSE

To provide an updated review of the diagnosis and pharmacotherapy of nontuberculous mycobacteria pulmonary disease (NTM-PD) and summarize guideline recommendations for an interdisciplinary treatment approach.

SUMMARY

A systemic approach was taken in which all articles in English in MEDLINE and PubMed were reviewed. DAILYMED was used to assess drug package inserts. Analysis of NTM treatment guidelines is summarized in the article with a focus on medications, dosing, interactions, and medication monitoring.

CONCLUSION

It is critical to manage patients with NTM with a multidisciplinary team approach. Treatment is prolonged and expensive, and the potential for drug toxicity, adverse effects, and drug interactions requires monitoring. Clinical pharmacists play a role in the management of NTM.

Anxiety and depression in patients with nontuberculous mycobacterial pulmonary disease: a prospective cohort study in South Korea

BACKGROUND

The mental health of patients with nontuberculous mycobacterial pulmonary disease (NTM-PD) has been underestimated.

RESEARCH QUESTION

What is the prevalence of, associated factors for, and clinical impact of anxiety and depression in patients with NTM-PD?

STUDY DESIGN AND METHODS

Among the patients diagnosed with NTM-PD between July 1, 2011 and December 31, 2019, who were a part of Seoul National University Hospital's prospective cohort, we included those who completed the Hospital Anxiety and Depression Scale (HADS) at least twice. Multivariable logistic regression analysis was used to identify the factors associated with anxiety and depression. Multilevel mixed-effects regression was used to analyze the HADS scores' longitudinal trends.

RESULTS

A total of 368 patients were included in this study, including 84 (22.8%) with anxiety (HADS-A score ≥8) and 83 (22.5%) with depression (HADS-D score ≥8). The presence of cough (adjusted odds ratio [aOR] 2.01, 95% confidence interval [CI] 1.19-3.39) and febrile sensation (aOR 4.45, 95% CI 2.13-9.30) were associated with anxiety, whereas dyspnea (aOR 4.13, 95% CI 1.38-12.37) and febrile sensation (aOR 2.91, 95% CI 1.38-6.13) were associated with depression. Although the HADS scores of patients with anxiety or depression at the time of enrollment and throughout the follow-up period were higher than those without, these scores declined significantly within one year after enrollment. Patients with anxiety (P=0.006) or depression (P=0.004) received antibiotic treatment more frequently than those without. Treatment outcomes did not differ depending on the initial anxiety or depression status.

INTERPRETATION

Anxiety and depression were common in patients with NTM-PD and were associated with patient-reported symptoms. While these persisted over time, the treatment outcomes did not differ.

Nontuberculous mycobacterial lung disease caused by Mycobacterium avium complex - disease burden, unmet needs, and advances in treatment developments

INTRODUCTION

Nontuberculous mycobacterial (NTM) lung disease (LD) is the most common clinical manifestation of NTM infection and is a growing health concern. Up to 85% of NTM-LD cases are caused by Mycobacterium avium complex (MAC). Increased awareness of NTM-LD caused by MAC is needed as patients with this disease experience substantial burden and unmet treatment needs.

AREAS COVERED

This review provides clinicians and regulatory and healthcare decision makers an overview of the clinical, economic, and humanistic burden of NTM-LD and the unmet treatment needs faced by patients and clinicians. The review focuses on NTM-LD caused by MAC. A summary of the 2020 NTM guidelines specifically for MAC-LD and an overview of novel treatment options, including amikacin liposome inhalation suspension (ALIS) as the first approved therapy for refractory MAC-LD, and investigational drugs in testing phase are provided.

EXPERT OPINION

Key advancements in NTM-LD management include recent updates to clinical practice guidelines, approval of ALIS for the treatment of refractory MAC-LD, and ongoing clinical trials of investigational treatments. Yet opportunities still exist to improve patient outcomes, including development of better screening tools, such as reliable and responsive biomarkers to help identify high-risk patients, and addressing unmet treatment needs.

Outcomes of adjunctive surgery for nontuberculous mycobacterial pulmonary disease

Background

Owing to the unsatisfactory results of antibiotic treatment alone, surgical resection is currently considered as adjunctive therapy in patients with nontuberculous mycobacterial pulmonary disease (NTM-PD). However, reports regarding the outcomes of surgery vary considerably by institution. Here, we investigated the surgical outcomes and risk factors associated with unfavorable outcomes after surgery.

Methods

We analyzed patients with NTM-PD who underwent pulmonary resection at Seoul National University Hospital between January 1, 2006, and December 31, 2020, and assessed the types of surgical procedures, complications, and long-term outcomes. Multivariate logistic regression analysis was used to identify the risk factors associated with treatment refractoriness or recurrence after surgery.

Results

Among 67 patients who underwent surgery during the study period, the most common indication for surgery was persistent culture positivity despite rigorous medical treatment (80.6%), followed by longstanding cavitary lesions or radiographic aggravation (10.4%) and massive hemoptysis (4.5%). Among 53 patients with positive mycobacterial cultures at the time of surgery, 38 (71.7%) achieved initial negative culture conversion, 9 (17.0%) of whom experienced recurrence. Nine (13.4%) patients experienced postoperative complications, which were managed without lasting morbidity and mortality. Female sex (adjusted odds ratio [aOR] 6.63; 95% confidence interval [CI] 1.04–42.4; P = .046), preoperative positive mycobacterial culture (aOR 5.87; 95 %CI 1.04–33.08; P = .045), and residual lesions (aOR 6.86; 95 %CI 1.49–31.56; P = .013) were associated with refractoriness or recurrence.

Conclusions

Pulmonary resection is a reasonable treatment modality for patients with refractory NTM-PD or major complications such as massive hemoptysis. The potential risk factors associated with unfavorable outcomes included female sex, preoperative positive mycobacterial culture, and residual lesions after surgery.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01679-0.

Amikacin Liposome Inhalation Suspension for Mycobacterium avium Complex Lung Disease: A 12-Month Open-Label Extension Clinical Trial

Rationale: Patients with refractory Mycobacterium avium complex (MAC) lung disease have limited treatment options. In the CONVERT study, amikacin liposome inhalation suspension (ALIS) added to guideline-based therapy (GBT) increased culture conversion rates versus GBT alone by Month 6. Limited data are available regarding >6-month treatment in a refractory population.

Objectives: Evaluate 12-month safety, tolerability, and efficacy of ALIS+GBT.

Methods: Adults with refractory MAC lung disease not achieving culture conversion by CONVERT Month 6 could enroll in this open-label extension (INS-312) to receive 590 mg once-daily ALIS+GBT for 12 months. Two cohorts enrolled: the “ALIS-naive” cohort included patients randomized to GBT alone in CONVERT, and the “prior-ALIS” cohort included those randomized to ALIS+GBT in CONVERT. Safety and tolerability of ALIS over 12 months (primary endpoint) and culture conversion by Months 6 and 12 were assessed.

Results: In the ALIS-naive cohort, 83.3% of patients (n = 75/90) experienced respiratory treatment-emergent adverse events (TEAEs), and 35.6% (n = 32) had serious TEAEs; 26.7% (n = 24) achieved culture conversion by Month 6 and 33.3% (n = 30) by Month 12. In the prior-ALIS cohort, 46.6% of patients (n = 34/73) experienced respiratory TEAEs, and 27.4% (n = 20) had serious TEAEs; 9.6% (n = 7) achieved culture conversion by Month 6 (≤14 mo ALIS exposure) and 13.7% (n = 10) by Month 12 (≤20 mo ALIS exposure). Nephrotoxicity-related TEAEs and measured hearing decline were infrequent in both cohorts.

Conclusions: In up to 20 months of ALIS use, respiratory TEAEs were common, nephrotoxicity and hearing decline were infrequent, and culture conversion continued beyond 6 months of therapy.

Clinical trial registered with www.clinicaltrials.gov (NCT02628600).

Serum GPL core antibody levels are associated with disease activity and treatment outcomes in Mycobacterium avium complex lung disease following first line antibiotic treatment

BACKGROUND

No objective serum biomarkers of disease course or treatment outcome of Mycobacterium avium complex lung disease (MAC-LD) presently exist. Serum IgA antibody levels against the glycopeptidolipid (GPL) core have good diagnostic accuracy for MAC-LD. However, their usefulness for monitoring and predicting disease course and outcome of MAC-LD following first-line antibiotic treatment remains unclear.

METHODS

We conducted a single-center retrospective cohort study to investigate the utility of serial measurements of GPL core IgA antibodies for monitoring disease course in 133 patients with MAC-LD following first-line antibiotic treatment.

RESULTS

Patients were classified into treatment failure [n = 46 (34.6%)], recurrence [n = 19 (14.3%)], or treatment success [n = 68 (51.1%)] groups according to bacteriological outcomes after chemotherapy. Pretreatment serum anti-GPL core IgA levels in the treatment success group were similar to those in the treatment failure and recurrence groups (P = 0.6431 and P = 0.9045, respectively). In the treatment success group, serum anti-GPL core IgA levels were significantly and continuously reduced after initiating antibiotic treatment. No significant reductions in anti-GPL core IgA levels were observed in either the treatment failure or recurrence groups. Reduced levels of GPL core antibodies following antibiotic treatment correlated well with treatment outcomes (P = 0.0045).

CONCLUSION

In this study, by performing serial measurements, we found that GPL core antibody levels were associated with disease activity and treatment outcomes in patients with MAC-LD. Time course analysis of anti-GPL core IgA levels clearly differentiated between patients who achieved treatment success and those who experienced treatment failure or disease recurrence.

Rheumatoid arthritis with nontuberculous mycobacterial pulmonary disease: a retrospective, single-centre cohort study

OBJECTIVES

Nontuberculous mycobacterial pulmonary disease (NTM-PD) is a rare but important comorbidity of rheumatoid arthritis (RA). Our objective was to investigate the association between NTM-PD and RA, especially regarding the immunosuppressive treatment of RA such as biological disease-modifying antirheumatic drugs (bDMARDs).

METHODS

We conducted a retrospective, single-centre cohort study. All RA patients regularly followed up at our rheumatology division in December 2012 were included in the study, and followed for 5 years.

RESULTS

At baseline, 26 of 1639 RA patients had NTM-PD. During the observation period, 14 were newly diagnosed with NTM-PD. For new diagnosis of NTM-PD, bDMARD use at baseline was not a significant risk factor. Among the 40 patients with NTM-PD, 16 were treated with a total of 27 bDMARDs after NTM-PD diagnosis. They did not present with a greater exacerbation of NTM-PD than those not treated with bDMARDs (25 vs. 17%, p = .52). A total of 55 patients died, but nobody died of NTM-PD. NTM-PD was not associated with worse mortality in multivariate analysis (hazard ratio, 2.0; 95% CI, 0.6-6.4; p = .26).

CONCLUSIONS

Biological DMARD was not associated with worse prognosis of NTM-PD. Careful use of bDMARDs could be tolerated in RA patients with NTM-PD.

Radiographic severity and treatment outcome of Mycobacterium abscessus complex pulmonary disease

INTRODUCTION

The lack of reliable predictors for the treatment response complicates decisions to initiate treatment in patients with Mycobacterium abscessus complex pulmonary disease (MABC-PD). We aimed to investigate whether baseline radiographic disease severity is associated with treatment outcome in MABC-PD.

METHOD

We retrospectively analyzed 101 patients with MABC-PD (54 with M. abscessus-PD and 47 with M. massiliense-PD) treated in a tertiary referral hospital between January 2006 and December 2019. Using chest computed tomography images, baseline radiographic disease severity was quantitatively scored according to five categories of radiographic lesions (bronchiectasis, bronchiolitis, cavities, nodules, and consolidation).

RESULTS

Treatment success was achieved in 53.7% of patients with M. abscessus-PD and 85.1% of patients with M. massiliense-PD. Higher overall scores for baseline radiographic disease severity were associated with treatment failure in patients with M. massiliense-PD (aOR 1.35, 95% CI 1.02-1.79 for each 1-point increase in severity score), as well as in patients with M. abscessus-PD (aOR 1.15, 95% CI 1.00-1.33). This was particularly prominent in patients with overall severity score of ≥14 (aOR 31.16, 95% CI 1.12-868.95 for M. massiliense-PD and aOR 3.55, 95% CI 1.01-12.45 for M. abscessus-PD). Among variable radiographic abnormalities, the score for cavitary lesion severity was associated with treatment failure in patients with M. abscessus-PD (aOR 1.26, 95% CI 1.01-1.56), but not in patients with M. massiliense-PD.

CONCLUSIONS

Given the association between baseline radiographic disease severity and treatment outcome, initiating treatment should be actively considered before significant progression of radiographic lesions in patients with MABC-PD.

The role of amikacin in the treatment of nontuberculous mycobacterial disease

Introduction: Guidelines recommend the use of amikacin in the treatment of nontuberculous mycobacterial (NTM) disease. The authors have evaluated the evidence for the position of amikacin in NTM disease treatment.Areas covered: The authors performed a literature search for original research on amikacin in NTM disease, including its mechanism of action, emergence of resistance, pre-clinical and clinical investigations.Expert opinion: Amikacin shows moderate in vitro activity against the clinically most relevant NTM species (M. avium complex and M. abscessus). It is synergistic with ethambutol, clofazimine, and macrolides and these combinations are effective in animal models. Liposomal encapsulation increases amikacin efficacy. Clinically, the recommended dose of 15 mg/kg intravenous amikacin does not lead to PK/PD target attainment in all patients and a positive impact on long-term treatment outcomes remains unproven in both M. avium complex and M. abscessus disease. Adding the amikacin liposome inhalation suspension did prove to be effective in short and long term in patients not responding to recommended treatment for M. avium complex pulmonary disease. Its optimal use in M. avium complex and M. abscessus pulmonary disease warrants further evaluation.

Clofazimine for treatment of multidrug-resistant non-tuberculous mycobacteria

BACKGROUND

/QUESTION: Nontuberculous mycobacteria (NTM) infections are increasingly detected but difficult to cure given complex drug-resistance patterns. Select U.S. centers have incorporated clofazimine in the treatment of NTM but experience is limited as procurement restrictions hamper widespread use.

METHODS

A prospective cohort study was performed in patients diagnosed with pulmonary or extrapulmonary NTM infection and treated with clofazimine between February 2015 and April 2019 at a tertiary referral hospital. Treatment success was defined by a combined outcome of clinical stabilization, microbiologic cure and radiologic improvement. Secondary outcomes included all-cause mortality and time to sputum culture conversion. Uni/multi-variate regression were used to define associations between pre-determined predictor variables and overall treatment outcome.

RESULTS

Of 44 patients enrolled, 39 (89 %) received clofazimine along with a median of 3 concomitant antibiotics. Thirty-one (80 %) of patients had pulmonary NTM infection, with Mycobacterium abscessus group and Mycobacterium avium complex being the most common species groups identified. Of 36 people with evaluable outcomes, 35 (97 %) survived and 22 (58 %) had treatment success, including 12 of 19 (63 %) with Mycobacterium abscessus group. In multivariate analysis, patients with Mycobacterium abscessus group were more likely to experience treatment success (OR 18.22, 95%CI 0.972-341.43, p = 0.052), while macrolide resistance predicted a lack of treatment success (OR 0.053, 95%CI 0.003-0.841, p = 0.037). Clofazimine was well-tolerated.

CONCLUSION

Adding clofazimine to multi-class antibiotic regimens for drug-resistant NTM infection led to treatment success in the majority treated. Randomized controlled studies are needed to determine the individual impact of clofazimine within an otherwise optimized drug regimen.

Trends in the Nontuberculous Mycobacterial Disease Mortality Rate in Japan: A Nationwide Observational Study, 1997-2016

BACKGROUND

The incidence of nontuberculous mycobacterial (NTM) infections has been increasing worldwide, becoming a significant healthcare burden especially among elderly people. This study aimed to evaluate the trends in NTM-associated mortality in Japan.

METHODS

This study used vital statistics data and data on all NTM-associated deaths (N = 18 814) among individuals aged ≥40 years in Japan from 1997 to 2016. We calculated the crude and age-adjusted mortality rates by age and sex and used joinpoint regression to analyze trends and estimate the average annual percentage change (AAPC). We compared crude NTM- and tuberculosis-associated mortality rates by sex.

RESULTS

The overall crude annual mortality rate increased from 0.63/100 000/year in 1997 to 1.93/100 000/year in 2016 and was the highest among individuals aged 80-84 years. The AAPC of the crude mortality rates among men of all ages and women aged 40-59 years were stable but increased among women aged 60-79 years (3.5%; 95% confidence interval [CI], 2.8-4.3) and ≥80 years (4.3%; 95% CI, 3.7-4.9). Among men, the age-adjusted mortality rates did not show a significant trend, while among women, the rates increased over the study period (AAPC, 4.6%; 95% CI, 2.7-6.6). In women, the crude NTM-associated mortality rate exceeded the tuberculosis mortality rate in 2014, 2015, and 2016.

CONCLUSIONS

NTM mortality increased in Japan between 1997 and 2016, especially among the elderly female population. Given the increasing NTM-associated mortality and the susceptible aging population, public health authorities in Japan should pay greater attention to NTM infections.

Nontuberculous Mycobacteria

Nontuberculous mycobacteria (NTM) are ubiquitous in the environment and 193 species of NTM have been discovered thus far. NTM species vary in virulence from benign environmental organisms to difficult-to-treat human pathogens. Pulmonary infections remain the most common manifestation of NTM disease in humans and bronchiectasis continues to be a major risk factor for NTM pulmonary disease (NTM PD). This article will provide a useful introduction and framework for clinicians involved in the management of bronchiectasis and NTM. It includes an overview of the epidemiology, pathogenesis, diagnosis, and management of NTM PD. We will address the challenges faced in the diagnosis of NTM PD and the importance of subspeciation in guiding treatment and follow-up, especially in Mycobacterium abscessus infections. The treatment of both Mycobacterium avium complex and M. abscessus, the two most common NTM species known to cause disease, will be discussed in detail. Elements of the recent ATS/ERS/ESCMID/IDSA NTM guidelines published in 2020 will also be reviewed.

Posttreatment Lymphopenia Is Associated With an Increased Risk of Redeveloping Nontuberculous Lung Disease in Patients With Mycobacterium avium Complex Lung Disease

BACKGROUND

Lymphopenia has been reported as a risk factor for poor prognosis in various infectious diseases, including Mycobacterium avium complex lung disease (MAC-LD), and recurrence in several infectious diseases. However, the association between lymphopenia and the risk of redeveloping nontuberculous lung disease (NTM-LD) after completed treatment for MAC-LD is unknown.

METHODS

We performed a retrospective cohort study with 147 patients with MAC-LD who successfully completed guideline-based therapy. Lymphopenia was defined as an absolute lymphocyte count (ALC) <1000 cells/μL based on commonly accepted reference values.

RESULTS

During the median follow-up period of 41.9 months after treatment completion, 59 (40.1%) patients redeveloped NTM-LD. Patients with NTM-LD redevelopment had significantly lower posttreatment ALCs (median, 1260 vs 1420 cells/μL) than those without, and the univariate Cox proportional hazard analysis identified posttreatment ALC as a predictive factor for redevelopment (hazard ratio, .94 [95% confidence interval, .89-.99] for every increase of 100 cells/μL; P = .04). In the multivariate analysis, posttreatment ALC and the extent of bronchiectasis were independently associated with NTM-LD redevelopment. The cumulative rate of NTM-LD redevelopment was significantly higher in patients with posttreatment lymphopenia than in those without (P = .008).

CONCLUSIONS

Posttreatment lymphopenia could predict an increased risk of NTM-LD redevelopment after completed treatment for MAC-LD.

Treatment outcomes of nontuberculous mycobacterial pulmonary disease in lung transplant recipients

BACKGROUND

Lung transplant (LTX) recipients are at risk miscellaneous infections, among whom the clinical significance of nontuberculous mycobacteria (NTM) is increasingly recognized. Despite anti-mycobacterial therapy becoming standardized worldwide, there is a lack of data on treatment outcomes in LTX recipients who develop NTM-pulmonary disease (PD). We aimed to review the treatment outcomes of NTM-PD among LTX recipients in our center.

METHODS

Patients who underwent LTX from January 2013 to December 2014 were consecutively enrolled in the retrospective cohort, with follow-up of data retrieved to December 2017. Clinical and radiological improvement and culture conversion after anti-mycobacterial therapy were reviewed in those who developed post-transplant NTM-PD.

RESULTS

Sixteen of 230 LTX recipients developed post-transplant NTM-PD. Ten of 16 patients with post-transplant NTM-PD were treated with macrolide-containing anti-mycobacterial therapy, leading to clinical improvement in 5/10 (50%), radiological improvement in 5/10 (50%) and culture conversion in 6/10 (60%) patients.

CONCLUSION

Anti-mycobacterial therapy may relieve pulmonary symptoms and reduce microbial load among individuals with post-transplant NTM-PD.

DNA Methylation Profiling for the Diagnosis and Prognosis of Patients with Nontuberculous Mycobacterium Lung Disease

The incidence of nontuberculous Mycobacterium (NTM) lung disease is rapidly increasing; however, its diagnosis and prognosis remain unclear while selecting patients who will respond to appropriate treatment. Differences in DNA methylation patterns between NTM patients with good or poor prognosis could provide important therapeutic targets. We used the Illumina MethylationEPIC (850k) DNA methylation microarray to determine the pattern between differentially methylated regions (DMRs) in NTM patients with good or poor prognosis (n = 4/group). Moreover, we merged and compared 20 healthy controls from previous Illumina Methylation450k DNA methylation microarray data. We selected and visualized the DMRs in the form of heatmaps, and enriched terms associated with these DMRs were identified by functional annotation with the “pathfinder” package. In total, 461 and 293 DMRs (|Log2 fold change| > 0.1 and P < 0.03) were more methylated in patients with four poor and four good prognoses, respectively. Furthermore, 337 and 771 DMRs (|Log2 fold change| > 0.08 and P < 0.001) were more methylated in eight NTM patients and 20 healthy controls, respectively. TGFBr1 was significantly less methylated, whereas HLA-DR1 and HLA-DR5 were more methylated in patients with poor prognosis (compared to those with good prognosis). LRP5, E2F1, and ADCY3 were the top three less-methylated genes in NTM patients (compared with the controls). The mTOR and Wnt signaling pathway-related genes were less methylated in patients with NTM. Collectively, genes related to Th1- cell differentiation, such as TGFBr1 and HLA-DR, may be used as biomarkers for predicting the treatment response in patients with NTM lung disease.

Computed Tomography in Adults with Bronchiectasis and Nontuberculous Mycobacterial Pulmonary Disease: Typical Imaging Findings

Among patients with bronchiectasis, nontuberculous mycobacterial pulmonary disease (NTM-PD) ranged between 1 and 6% and it is suspected that its prevalence is underestimated. Our aim was to evaluate differences in computed tomography (CT) features in patients with bronchiectasis, with and without NTM-PD, in order to facilitate earlier diagnosis in the future. In addition, we evaluated longitudinal changes after successful NTM-PD treatment. One hundred and twenty-eight CTs performed in adults with bronchiectasis were scored for the involvement, type, and lobar distribution of bronchiectasis, bronchial dilatation, and bronchial wall thickening according to Reiff. In addition, associated findings, such as mucus plugging, tree-in-bud, consolidations, ground-glass opacities, interlobular thickening, intralobular lines, cavities, and atelectasis, were registered. Patients with NTM-PD (n = 36), as defined by ATS/IDSA diagnostic criteria, were compared to bronchiectasis patients without NTM-PD (n = 92). In twelve patients with an available consecutive CT scan after microbiological cure of NTM-PD imaging findings were also scored according to Kim and compared in the course. In patients with NTM-PD, there was a higher prevalence of bronchiectasis in the middle lobes (p < 0.001), extended bronchiolitis (p = 0.032) and more small and large nodules (p < 0.001). Furthermore, cavities turned out to be larger (p = 0.038), and walls thickened (p = 0.019) and extended (p = 0.016). Patients without NTM more often showed peripheral ground-glass opacities (0.003) and interstitial changes (p = 0.001). CT findings decreased after successful NTM-PD treatment in the follow-up CT; however, without statistical significance for most features (p = 0.056), but bronchiolitis was the only significantly reduced score item (p = 0.043). CT patterns in patients with bronchiectasis and NTM-PD differ from those of patients with bronchiectasis without NTM-PD, although the findings are non-specific radiological features. Follow-up CT findings after microbiological cure differed interindividual regarding the decline in imaging features. Our findings may help practitioners to identify NTM-PD in patients with bronchiectasis. Further research is needed regarding the use of CT as a potential imaging biomarker for the evaluation of treatment response.

Impact of Susceptibility to Injectable Antibiotics on the Treatment Outcomes of Mycobacterium abscessus Pulmonary Disease

Background

Current guidelines recommend a susceptibility-based regimen for Mycobacterium abscessus subspecies abscessus pulmonary disease (MAB-PD), but the evidence is weak. We aimed to investigate the association between treatment outcomes and in vitro drug susceptibility to injectable antibiotics in MAB-PD patients.

Methods

We enrolled MAB-PD patients treated with intravenous amikacin and beta-lactams for ≥4 weeks at 4 referral hospitals in Seoul, South Korea. Culture conversion and microbiological cure at 1 year were evaluated based on susceptibility to injectable antibiotics among patients treated with those antibiotics for ≥2 weeks.

Results

A total of 82 patients were analyzed. The mean age was 58.7 years, and 65.9% were women. Sputum culture conversion and microbiological cure were achieved in 52.4% and 41.5% of patients, respectively. Amikacin was the most common agent to which the M. abscessus subspecies abscessus isolates were susceptible (81.7%); 9.8% and 24.0% of the isolates were resistant to cefoxitin and imipenem, respectively. The clarithromycin-inducible resistance (IR) group (n = 65) had a lower microbiological cure rate than the clarithromycin-susceptible group (35.4% vs 64.7%). The treatment outcomes appeared to be similar regardless of in vitro susceptibility results with regard to intravenous amikacin, cefoxitin, imipenem, and moxifloxacin. In the subgroup analysis of the clarithromycin-IR group, the treatment outcomes did not differ according to antibiotic susceptibility.

Conclusions

We did not find evidence supporting the use of susceptibility-based treatment with intravenous amikacin and beta-lactams in patients with MAB-PD. Further research is required.

Isolation of non-tuberculous mycobacteria among tuberculosis patients, a study from a tertiary care hospital in Lahore, Pakistan

BACKGROUND

There is scarce knowledge on the prevalence of diseases caused by non-tuberculous mycobacteria (NTM) in Pakistan. In the absence of culture and identification, acid-fast bacilli (AFB) causing NTM disease are liable to be misinterpreted as tuberculosis (TB). Introduction of nucleic acid amplification testing for Mycobacterium tuberculosis complex (MTBC) offers improved diagnostic accuracy, compared with smear microscopy, and also assists in differentiating MTBC from other mycobacteria. This study aimed to investigate the prevalence of NTM among patients investigated for TB and describe NTM disease and treatment outcomes at a tertiary care hospital in Pakistan.

METHODS

This is a retrospective study, data on NTM isolates among culture-positive clinical samples over 4 years (2016-19) was retrieved from laboratory records. Information on clinical specimens processed, AFB smear results, and for the AFB positive isolates, results of species identification for MTBC, and for NTM isolates, results of species characterization and drug susceptibility testing was collected. Additional clinical data including patient characteristics, treatment regimens, and outcomes were collected for patients with NTM disease treated at Gulab Devi Hospital, Lahore.

RESULTS

During the study period, 12,561 clinical specimens were processed for mycobacterial culture and 3673 (29%) were reported positive for AFB. Among these 3482 (95%) were identified as MTBC and 191 (5%) as NTM. Among NTM, 169 (88%) were isolated from pulmonary and 22 (12%) from extrapulmonary specimens. Results of NTM speciation were available for 60 isolates and included 55% (n = 33) M. avium complex and 25% (n = 15) M. abscesses. Among these patients, complete clinical records were retrieved for 12 patients with pulmonary disease including nine infected with M. avium complex and three with M. abscessus. All 12 patients had a history of poor response to standard first-line anti-TB treatment. Ten patients were cured after 18 months of treatment, whereas, one with M. abscessus infection died and another was lost to follow up.

CONCLUSION

In TB endemic areas, NTM can be misdiagnosed as pulmonary TB leading to repeated failed anti-TB treatment and increased morbidity, emphasizing the need for improved diagnosis.

Amikacin Liposome Inhalation Suspension for Refractory Mycobacterium avium Complex Lung Disease: Sustainability and Durability of Culture Conversion and Safety of Long-term Exposure

BACKGROUND

In the CONVERT study, treatment with amikacin liposome inhalation suspension (ALIS) added to guideline-based therapy (GBT) met the primary end point of increased culture conversion by month 6 in patients with treatment-refractory Mycobacterium avium complex lung disease (ALIS plus GBT, 29% [65/224] vs GBT alone, 8.9% [10/112]; P < .0001).

RESEARCH QUESTION

In patients who achieved culture conversion by month 6 in the CONVERT study, was conversion sustained (negative sputum culture results for 12 months with treatment) and durable (negative sputum culture results for 3 months after treatment) and were there any additional safety signals associated with a full treatment course of 12 months after conversion?

STUDY DESIGN AND METHODS

Adults were randomized 2:1 to receive ALIS plus GBT or GBT alone. Patients achieving culture conversion by month 6 continued therapy for 12 months followed by off-treatment observation.

RESULTS

More patients randomized to ALIS plus GBT (intention-to-treat population) achieved conversion that was both sustained and durable 3 months after treatment vs patients randomized to GBT alone (ALIS plus GBT, 16.1% [36/224] vs GBT alone, 0% [0/112]; P < .0001). Of the patients who achieved culture conversion by month 6, 55.4% of converters (36/65) in the ALIS plus GBT treated arm vs no converters (0/10) in the GBT alone arm achieved sustained and durable conversion (P = .0017). Relapse rates through 3 months after treatment were 9.2% (6/65) in the ALIS plus GBT arm and 30.0% (3/10) in the GBT alone arm. Common adverse events among ALIS plus GBT-treated patients (dysphonia, cough, dyspnea, hemoptysis) occurred mainly within the first 8 months of treatment.

INTERPRETATION

In a refractory population, conversion was sustained and durable in more patients treated with ALIS plus GBT for 12 months after conversion than in those treated with GBT alone. No new safety signals were associated with 12 months of treatment after conversion.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT02344004; URL: www.clinicaltrials.gov.

A Low Body Mass Index Is Associated with Unsuccessful Treatment in Patients with Mycobacterium avium Complex Pulmonary Disease

Background: A low body mass index (BMI) has been reported to be a poor prognostic factor for Mycobacterium avium complex pulmonary disease (MAC-PD). The purpose of this study was to clarify the clinical features of MAC-PD in cases with a low BMI. Methods: This retrospective study analyzed the data of patients diagnosed with MAC-PD at Saga University Hospital between 2008 and 2019. The analyzed patient characteristics included age, gender, BMI, symptoms, laboratory data, chest computed tomography findings, and the treatment courses. We also investigated the factors associated with successful treatment. Results: In total, 144 patients were included in this study. The low-BMI group (BMI < 18.5 kg/m²) had a higher incidence of sputum, Mycobacterium intracellurare infection, and cavitary lesions, in addition to lower blood lymphocyte counts, higher neutrophil–lymphocyte ratios, and a lower prognostic nutritional index (PNI) when compared to the preserved-BMI group (BMI ≥ 18.5 kg/m²). Sixty-six of the 144 patients (45.8%) received treatment. Hemosputum, acid-fast bacillus sputum smear positivity, low lymphocyte counts, a low PNI, and unsuccessful treatment (48.5% vs. 24.2%, p < 0.05) were found to be associated with a low BMI. Conclusions: A low BMI is associated with cavitary lesions, malnutrition, and unsuccessful treatment in MAC-PD.

Variability in the Management of Adults With Pulmonary Nontuberculous Mycobacterial Disease

BACKGROUND

The increasing global prevalence of pulmonary nontuberculous mycobacteria (NTM) disease has called attention to challenges in NTM diagnosis and management. This study was conducted to understand management and outcomes of patients with pulmonary NTM disease at diverse centers across the United States.

METHODS

We conducted a 10-year (2005-2015) retrospective study at 7 Vaccine and Treatment Evaluation Units to evaluate pulmonary NTM treatment outcomes in human immunodeficiency virus-negative adults. Demographic and clinical information was abstracted through medical record review. Microbiologic and clinical cure were evaluated using previously defined criteria.

RESULTS

Of 297 patients diagnosed with pulmonary NTM, the most frequent NTM species were Mycobacterium avium-intracellulare complex (83.2%), M. kansasii (7.7%), and M. abscessus (3.4%). Two hundred forty-five (82.5%) patients received treatment, while 45 (15.2%) were followed without treatment. Eighty-six patients had available drug susceptibility results; of these, >40% exhibited resistance to rifampin, ethambutol, or amikacin. Of the 138 patients with adequate outcome data, 78 (56.5%) experienced clinical and/or microbiologic cure. Adherence to the American Thoracic Society/Infectious Diseases Society of America (ATS/IDSA) treatment guidelines was significantly more common in patients who were cured (odds ratio, 4.5, 95% confidence interval, 2.0-10.4; P < .001). Overall mortality was 15.7%.

CONCLUSIONS

Despite ATS/IDSA Guidelines, management of pulmonary NTM disease was heterogeneous and cure rates were relatively low. Further work is required to understand which patients are suitable for monitoring without treatment and the impact of antimicrobial therapy on pulmonary NTM morbidity and mortality.

Tedizolid vs Linezolid for the Treatment of Nontuberculous Mycobacteria Infections in Solid Organ Transplant Recipients

Background

Treatment options for nontuberculous mycobacteria (NTM) infections are limited by the pathogen's intrinsic resistance profile and toxicities. Tedizolid and linezolid display in vitro activity against NTM species. However, safety data and treatment outcomes are limited in the solid organ transplant (SOT) population.

Methods

This was a single-center retrospective cohort study of adult SOT recipients receiving linezolid or tedizolid for an NTM infection from January 1, 2010, to August 31, 2019. The primary outcome compared the hematologic safety profiles of tedizolid vs linezolid. We also described nonhematological adverse drug events (ADEs) and therapy discontinuation rates. In an exploratory analysis, we assessed symptomatic microbiologic and clinical outcomes in those receiving tedizolid or linezolid for at least 4 weeks.

Results

Twenty-four patients were included (15 tedizolid, 9 linezolid). No differences were identified comparing the effects of tedizolid vs linezolid on platelet counts, absolute neutrophil counts (ANCs), and hemoglobin over 7 weeks using mixed-effects analysis of variance models. ANC was significantly decreased in both groups after 7 weeks of therapy (P = .04). Approximately 20% of patients in each arm discontinued therapy due to an ADE. Seven of 12 (58%) and 2 of 3 (67%) patients were cured or clinically cured with tedizolid- and linezolid-containing regimens, respectively.

Conclusions

This study suggests no significant safety benefit of tedizolid over linezolid for the treatment of NTM infections in SOT recipients. Tedizolid or linezolid-containing regimens demonstrated a potential benefit in symptomatic and microbiologic improvement. Larger cohorts are needed to further delineate the comparative role of linezolid and tedizolid for the treatment of NTM infections in SOT recipients.

Isolation and Characterization of vB_MsmS_Celfi: A New Mycobacterium tuberculosis Bacteriophage

Introduction: Because of the clinical relevance of Mycobacteria, and from a therapeutic perspective, there is an increasing interest to study phages that infect bacteria belonging to this genus. Materials and Methods: A phage was isolated from a soil sample, using Mycobacterium smegmatis as host. Its characterization included sequencing, annotation, and analysis of the genome, host range determination, and electron microscopy imaging. Results: Mycobacterium phage vB_MsmS_Celfi is a temperate phage able to infect Mycobacterium tuberculosis with high efficiency. From electron microscopy images, Celfi belongs to the Siphoviridae family. Genome analysis classified phage Celfi into cluster L, subcluster L2 of Actinobacteriophage clusters. Mycobacterium phage Celfi exhibits a Lysin B distant to those present in other members of the subcluster and other mycobacteriophages. Conclusions: The discovery of new phages that infect M. tuberculosis could contribute to the development of novel tools for detection systems and future treatment of the disease.

Clinical Implications of Size of Cavities in Patients With Nontuberculous Mycobacterial Pulmonary Disease: A Single-Center Cohort Study

Background

The presence of cavities is associated with unfavorable prognosis in patients with nontuberculous mycobacterial pulmonary disease (NTM-PD). However, little is known about the characteristics of such cavities and their impact on clinical outcomes. The aim of this study was to investigate the size of cavities and their implications on treatment outcomes and mortality in patients with NTM-PD.

Methods

We included patients diagnosed with NTM-PD at Seoul National University Hospital between January 1, 2007, and December 31, 2018. We measured the size of cavities on chest computed tomography scans performed at the time of diagnosis and used multivariable logistic regression and Cox proportional hazards regression analysis to investigate the impact of these measurements on treatment outcomes and mortality.

Results

The study cohort comprised 421 patients (noncavitary, n = 329; cavitary, n = 92) with NTM-PD. During a median follow-up period of 49 months, 118 (35.9%) of the 329 patients with noncavitary and 64 (69.6%) of the 92 patients with cavitary NTM-PD received antibiotic treatment. Cavities >2 cm were associated with worse treatment outcomes (adjusted odds ratio, 0.41; 95% CI, 0.17–0.96) and higher mortality (adjusted hazard ratio, 2.52; 95% CI, 1.09–5.84), while there was no difference in treatment outcomes or mortality between patients with cavities ≤2 cm and patients with noncavitary NTM-PD.

Conclusions

Clinical outcomes are different according to the size of cavities in patients with cavitary NTM-PD; thus, the measurement of the size of cavities could help in making clinical decisions.

Outcomes of Inhaled Amikacin-Containing Multidrug Regimens for Mycobacterium abscessus Pulmonary Disease

BACKGROUND

Mycobacterium abscessus pulmonary disease (M abscessus-PD) is challenging to treat because of its resistance to antibiotics.

RESEARCH QUESTION

What are the outcomes of treatment-naive patients with M abscessus-PD treated with inhaled amikacin-containing multidrug regimens?

STUDY DESIGN AND METHODS

We identified 82 treatment-naive patients with M abscessus-PD from a prospective observational cohort treated with regimens containing inhaled amikacin with or without clofazimine between March 2015 and June 2018 (ClinicalTrials.gov identifier: NCT00970801). During the initial phase, all patients received IV amikacin, imipenem (or cefoxitin), and oral azithromycin. Oral clofazimine was added in cases of (1) M abscessus subspecies abscessus (here M abscessus) or (2) M abscessus subspecies massiliense (here M massiliense) with cavitary lesions. During the continuation phase, amikacin was changed from an injectional to inhalational form.

RESULTS

Of 82 patients, 46 (56%) had M massiliense-PD and 36 (44%) had M abscessus-PD. Among 59 patients with nodular bronchiectatic disease (72%), 23 of 59 had a concurrent cavitary lesion. The remaining 23 patients (28%) had fibrocavitary disease. Twelve months after treatment initiation, cure was achieved in 53 patients (65%): 42 of 46 patients (91%) with M massiliense-PD and 11 of 36 patients (31%) with M abscessus-PD (P < .001). Symptomatic and radiologic improvements were observed in 72 patients (88%) and 64 patients (78%), respectively, with significantly greater improvement in patients with M massiliense-PD (symptom improvement, 96% vs 78% [P = .047]; improvement on CT scanning, 93% vs 61% [P = .002]).

INTERPRETATION

Inhaled amikacin with or without clofazimine in the regimen provides favorable treatment outcomes in M massiliense-PD. However, more effective treatments are needed for M abscessus-PD.

Aspergillus isolation in nontuberculous mycobacterial pulmonary disease: Associated with antimycobacterial treatment initiation but not response

PURPOSE

Chronic pulmonary aspergillosis is a serious complication of nontuberculous mycobacterial pulmonary disease (NTM-PD), and diagnosis remains challenging. The present study examined associations between the respiratory isolation of Aspergillus and the clinical characteristics and treatment outcomes of patients with NTM-PD.

METHODS

All patients meeting NTM-PD criteria as defined by the ATS/IDSA statement, with at least one respiratory sample cultured for fungi, were included in this retrospective cohort analysis. Patients with at least one respiratory sample isolating Aspergillus were compared to patients who did not isolate Aspergillus. The primary outcomes were culture conversion and radiologic evolution 12 months after NTM-PD treatment initiation.

RESULTS

During a 12 year period, 497 patients meeting the inclusion criteria were seen in our tertiary care center, of whom 130 grew Aspergillus. Median follow up after NTM-PD diagnosis was 46 months. Inhaled corticosteroid use, a nodular-bronchiectatic CT pattern and NTM-PD treatment initiation were more frequent in patients who isolated Aspergillus compared to those who did not (p-value respectively 0.01, 0.03 and < 0.001). Rates of culture conversion (63.0% vs. 62.2%, respectively; p-value 1) and radiologic evolution (improvement or stability in 69.7% vs. 77.2%, respectively; p-value 0.25) were not significantly different between treatment groups. Likewise, culture reversion rate and 5-year mortality were not significantly different. Additionally, A. fumigatus and repeated detection of Aspergillus were not associated with treatment outcomes.

CONCLUSION

There was no association between respiratory isolation of Aspergillus and NTM-PD treatment outcomes in this cohort. However, treatment for NTM-PD was initiated more frequently in patients who isolated Aspergillus.

Eradication success for non-tuberculous mycobacteria in children with cystic fibrosis

Non-tuberculous mycobacteria (NTM) are an emerging pathogen worldwide in both cystic fibrosis (CF) and non-CF pulmonary disease (PD), with reports suggesting an increasing prevalence [1, 2]. It is an opportunistic infection acquired from the environment [3], though conflicting evidence remains around person-to-person transmission [4, 5]. Recent evidence suggests that Mycobacterium abscessus complex (MABSC) may be the most detrimental airway infection to lung function in CF [6], yet its treatment remains poorly evidenced.

Non-tuberculous mycobacteria pulmonary disease affects cystic fibrosis lung health and increasingly affects children. This study reports treatment outcomes from a large CF centre, with eradication rates exceeding 60% for M. abscessus complex infection.https://bit.ly/2L8TdFM

First line treatment selection modifies disease course and long-term clinical outcomes in Mycobacterium avium complex pulmonary disease

The combination of rifamycin (RFP), ethambutol (EB), and macrolides is currently the standard regimen for treatment of Mycobacterium avium complex pulmonary disease (MAC-PD). However, poor adherence to the standardized regimens recommended by current guidelines have been reported. We undertook a single-centred retrospective cohort study to evaluate the long-term outcomes in 295 patients with MAC-PD following first line treatment with standard (RFP, EB, clarithromycin [CAM]) or alternative (EB and CAM with or without fluoroquinolones (FQs) or RFP, CAM, and FQs) regimens. In this cohort, 80.7% were treated with standard regimens and 19.3% were treated with alternative regimens. After heterogeneity was statistically corrected using propensity scores, outcomes were superior in patients treated with standard regimens. Furthermore, alternative regimens were significantly and independently associated with sputum non-conversion, treatment failure and emergence of CAM resistance. Multivariate cox regression analysis revealed that older age, male, old tuberculosis, diabetes mellitus, higher C-reactive protein, and cavity were positively associated with mortality, while higher body mass index and M. avium infection were negatively associated with mortality. These data suggest that, although different combination regimens are not associated with mortality, first line administration of a standard RFP + EB + macrolide regimen offers the best chance of preventing disease progression in MAC-PD patients.

Predictive modeling of nontuberculous mycobacterial pulmonary disease epidemiology using German health claims data

OBJECTIVES

Administrative claims data are prone to underestimate the burden of non-tuberculous mycobacterial pulmonary disease (NTM-PD).

METHODS

We developed machine learning-based algorithms using historical claims data from cases with NTM-PD to predict patients with a high probability of having previously undiagnosed NTM-PD and to assess actual prevalence and incidence. Adults with incident NTM-PD were classified from a representative 5% sample of the German population covered by statutory health insurance during 2011-2016 by the International Classification of Diseases, 10th revision code A31.0. Pre-diagnosis characteristics (patient demographics, comorbidities, diagnostic and therapeutic procedures, and medications) were extracted and compared to that of a control group without NTM-PD to identify risk factors.

RESULTS

Applying a random forest model (area under the curve 0.847; total error 19.4%) and a risk threshold of >99%, prevalence and incidence rates in 2016 increased 5-fold and 9-fold to 19 and 15 cases/100,000 population, respectively, for both coded and non-coded vs. coded cases alone.

CONCLUSIONS

The use of a machine learning-based algorithm applied to German statutory health insurance claims data predicted a considerable number of previously unreported NTM-PD cases with high probabilty.

High-Resolution CT Findings as Predictive Factors for Recurrent Nontuberculous Mycobacterial Pulmonary Disease after Successful Treatment

Despite long-term treatment for nontuberculous mycobacterial pulmonary disease (NTM-PD), recurrence is common. We aim to identify computed tomography (CT) findings that predict recurrence after successful treatment of NTM-PD. This retrospective study included 44 patients (12 men, 60 ± 11.2 years) successfully treated for NTM-PD between March 2009 and September 2016. Recurrence developed in 18 patients (40.9%) during follow-up (median, 852 days). CT scores for bronchiectasis, bronchiolitis, consolidation, cavities, and nodules at the initiation and termination of treatment were evaluated, then determined association with recurrence. We also assessed the diagnostic performance and reproducibility of CT scores. Patients with recurrent NTM-PD showed higher CT scores for bronchiectasis (p = 0.008), nodules (p = 0.006), consolidation (p = 0.033), and total CT scores (p = 0.017) at the time of treatment termination. On the contrary, only nodule score differed among the initial CT scores (p = 0.014). Regression analysis showed that the scores for bronchiectasis (odds ratio (OR) = 1.638, 95% confidence interval (CI) = 1.049-2.558, p = 0.030) and nodules (OR = 5.246, 95% CI = 1.370-20.087, p = 0.016) at treatment termination were significant predictors. The AUC of the regression model was 0.814 (95% CI = 0.689-0.939, p = 0.005). The interreader agreement for the total CT score was excellent (intraclass correlation coefficient = 0.841, p < 0.001). CT scores at the time of treatment termination can predict disease recurrence with good reproducibility.

Immune defects in patients with pulmonary Mycobacterium abscessus disease without cystic fibrosis

The prevalence of Mycobacterium abscessus infections in non-cystic fibrosis (CF) patients has increased in recent years. In this study, we investigate whether immune defects explain the apparent susceptibility to this opportunistic infection in non-CF patients.

We performed stimulations of peripheral blood mononuclear cells and whole blood from 13 patients with M. abscessus pulmonary disease and 13 healthy controls to investigate their cytokine production after 24 h and 7 days.

Patients were predominantly women (54%) with a mean age of 59 years; 62% had nodular bronchiectatic disease. Many patients had predisposing pulmonary diseases, such as COPD (46%), and asthma (23%). Patients with COPD showed an impaired interleukin (IL)-6 response to M. abscessus and a reduced IL-17 response to Candida, together with a M. abscessus-specific enhanced IL-22 production. Patients without COPD showed higher levels of interleukin-1 receptor antagonist (IL-1Ra), an anti-inflammatory molecule. Within the non-COPD patients, those with bronchiectasis showed defective interferon (IFN)-γ production in response to Candida albicans.

In conclusion, susceptibility to M. abscessus is likely determined by a combination of immunological defects and predisposing pulmonary disease. The main defect in the innate immune response was a shift of the ratio of IL-1β to IL-1Ra, which decreased the bioactivity of this pathway in the adaptive immune response. In the adaptive immune response there was defective IL-17 and IFN-γ production. Patients with COPD and bronchiectasis showed different cytokine defects. It is therefore crucial to interpret the immunological results within the clinical background of the patients tested.

Measurement of defects in both the innate and adaptive immune responses in patients with M. abscessus pulmonary disease show that susceptibility to M. abscessus is determined by a combination of immunological defects and predisposing pulmonary diseasehttps://bit.ly/2DtbycY

Outcomes of Inhaled Amikacin and Clofazimine-Containing Regimens for Treatment of Refractory Mycobacterium avium Complex Pulmonary Disease

Limited data are available regarding optimal treatment for refractory Mycobacterium avium complex-pulmonary disease (MAC-PD). We evaluated outcomes of inhaled amikacin (AMK) with clofazimine (CFZ) regimens as an add-on salvage therapy for refractory MAC-PD. We retrospectively analyzed 52 patients with refractory MAC-PD, characterized by persistently positive sputum cultures despite >6 months of treatment. Thirty-five (67%) patients had M. intracellulare-PD, and 17 (33%) patients had M. avium-PD. Twenty-seven (52%) patients received the salvage therapy for ≥12 months, whereas 25 (48%) patients were treated for <12 months due to adverse effects or other reasons. Seventeen (33%) patients had culture conversion: 10 (10/27) in the ≥12-month treatment group and seven (7/25) in the <12-month treatment group (p = 0.488). Microbiological cure, defined as maintenance of culture negativity, was achieved in 12 (23%) patients; six (6/12) with accompanying symptomatic improvement were considered to have reached cure. Clinical cure, defined as symptomatic improvement with <3 consecutive negative cultures, was achieved in three (6%) patients. Overall, 15 (29%) patients achieved favorable outcomes, including microbiological cure, cure, and clinical cure. Inhaled AMK with CFZ may provide favorable outcomes in some patients with refractory MAC-PD. However, given the adverse effects, more effective strategies are needed to maintain these therapeutic regimens.

Mycobacterium avium Complex: Addressing Gaps in Diagnosis and Management

Nontuberculous mycobacteria (NTM) are ubiquitous in the environment and an important cause of disease. The most common species causing pulmonary disease are members of Mycobacterium avium complex (MAC). MAC pulmonary disease (MAC-PD) can be chronic, debilitating, costly, and associated with a high mortality. However, MAC diagnoses are often delayed due to the nonspecific presentation of MAC-PD and radiological findings that overlap with other pulmonary diseases. Patients with risk factors and who meet the diagnostic criteria-which include clinical, radiological, and microbiologic criteria-should be considered for treatment. Diagnosis requires 2 or more positive sputum cultures or 1 bronchoscopic specimen culture. The recommendation for those who are treated is a 3-drug regimen including macrolide, rifamycin, and ethambutol that is continued for 12 months beyond sputum culture conversion to negative. MAC-PD is difficult to treat, with frequent drug-related side effects and suboptimal treatment outcomes. Refractory and recurrent disease is common, leading to lifelong follow-up of patients. There are limited treatment options for patients with macrolide-resistant or refractory disease. Amikacin liposome inhalation suspension is recommended for treatment-refractory patients whose cultures remain positive after 6 months of guideline-based therapy. Among the research priorities to improve patient outcomes and quality of life are developing new, more rapid diagnostic tests, investigating biomarkers associated with disease progression, and identifying new drugs and routes of administration as well as new, shorter, and better-tolerated regimens.

Treatment of Nontuberculous Mycobacterial Pulmonary Disease: An Official ATS/ERS/ESCMID/IDSA Clinical Practice Guideline

Nontuberculous mycobacteria (NTM) represent over 190 species and subspecies, some of which can produce disease in humans of all ages and can affect both pulmonary and extrapulmonary sites. This guideline focuses on pulmonary disease in adults (without cystic fibrosis or human immunodeficiency virus infection) caused by the most common NTM pathogens such as Mycobacterium avium complex, Mycobacterium kansasii, and Mycobacterium xenopi among the slowly growing NTM and Mycobacterium abscessus among the rapidly growing NTM. A panel of experts was carefully selected by leading international respiratory medicine and infectious diseases societies (ATS, ERS, ESCMID, IDSA) and included specialists in pulmonary medicine, infectious diseases and clinical microbiology, laboratory medicine, and patient advocacy. Systematic reviews were conducted around each of 22 PICO (Population, Intervention, Comparator, Outcome) questions and the recommendations were formulated, written, and graded using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) approach. Thirty-one evidence-based recommendations about treatment of NTM pulmonary disease are provided. This guideline is intended for use by healthcare professionals who care for patients with NTM pulmonary disease, including specialists in infectious diseases and pulmonary diseases.

Minimal Inhibitory Concentration of Clofazimine Among Clinical Isolates of Nontuberculous Mycobacteria and Its Impact on Treatment Outcome

BACKGROUND

Clofazimine has been regarded as a promising agent for the treatment of nontuberculous mycobacteria pulmonary disease (NTM-PD). However, its overall effectiveness in vitro and in the clinic remains unknown.

RESEARCH QUESTION

What is the minimal inhibitory concentration (MIC) of clofazimine in clinical isolates and the association between MICs and treatment outcome?

STUDY DESIGN AND METHODS

MICs for clofazimine were measured in clinical isolates from NTM-PD patients who participated in a prospective study at Seoul National University Hospital. The MIC was determined by using the broth microdilution concentration method. Correlation between MIC and conversion to negative of sputum culture with clofazimine was determined.

RESULTS

Of a total 189 isolates, 133 strains were Mycobacterium avium complex (MAC) and 40 strains were M abscessus. Although the clofazimine MICs for MAC ranged from 0.031 mg/L to 8 mg/L, the values obtained for M abscessus ranged from 0.031 mg/L to 16 mg/L. Of 20 patients who were treated with a regimen including clofazimine, eight achieved negative conversion of sputum culture. All patients with isolates exhibiting clofazimine MIC values ≤ 0.25 mg/L achieved culture conversion. The likelihood of culture conversion in patients with MIC value ≤ 0.25 mg/L was much higher than that of patients with MIC value > 0.5 mg/L (OR, 39.3; P = .021).

INTERPRETATION

The MICs of clofazimine varied widely in clinical isolates from patients with NTM-PD. Negative conversion of sputum culture with clofazimine use was associated with a lower MIC value. Clofazimine use could be considered in patients with NTM-PD when the MIC value is ≤ 0.25 mg/L.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT01616745; URL: www.clinicaltrials.gov.

Treatment of nontuberculous mycobacterial pulmonary disease: an official ATS/ERS/ESCMID/IDSA clinical practice guideline

Nontuberculous mycobacteria (NTM) represent over 190 species and subspecies, some of which can produce disease in humans of all ages and can affect both pulmonary and extrapulmonary sites. This guideline focuses on pulmonary disease in adults (without cystic fibrosis or human immunodeficiency virus infection) caused by the most common NTM pathogens such as Mycobacterium avium complex, Mycobacterium kansasii, and Mycobacterium xenopi among the slowly growing NTM and Mycobacterium abscessus among the rapidly growing NTM. A panel of experts was carefully selected by leading international respiratory medicine and infectious diseases societies (ATS, ERS, ESCMID, IDSA) and included specialists in pulmonary medicine, infectious diseases and clinical microbiology, laboratory medicine, and patient advocacy. Systematic reviews were conducted around each of 22 PICO (Population, Intervention, Comparator, Outcome) questions and the recommendations were formulated, written, and graded using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) approach. Thirty-one evidence-based recommendations about treatment of NTM pulmonary disease are provided. This guideline is intended for use by healthcare professionals who care for patients with NTM pulmonary disease, including specialists in infectious diseases and pulmonary diseases.

Serum Krebs von den Lungen-6 level in the disease progression and treatment of Mycobacterium avium complex lung disease

BACKGROUND AND OBJECTIVE

The lack of useful biomarkers reflecting the disease state limits the management of Mycobacterium avium complex lung disease (MAC-LD). We clarified the associations between serum KL-6 level, disease progression and treatment response.

METHODS

Resected lung tissues from MAC-LD patients were immunostained for KL-6. We compared serum KL-6 levels between MAC-LD and healthy control or bronchiectasis patients without nontuberculous mycobacterial lung disease (NTM-LD). Serum KL-6 level was assessed in a prospective observational study at Keio University Hospital between May 2012 and May 2016. We investigated associations between serum KL-6 level and disease progression and treatment response in patients untreated for MAC-LD on registration (n = 187).

RESULTS

The KL-6⁺ alveolar type 2 cell population in the lung and serum KL-6 level were significantly higher in MAC-LD patients than in controls. Serum KL-6 level in bronchiectasis patients without NTM-LD showed no significant increase. Of the 187 patients who did not receive treatment on registration, 53 experienced disease progression requiring treatment. Multivariable Cox analysis revealed that the serum KL-6 level (aHR: 1.18, P = 0.005), positive acid-fast bacilli smear (aHR: 2.64, P = 0.001) and cavitary lesions (aHR: 3.01, P < 0.001) were significantly associated with disease progression. The change in serum KL-6 (ΔKL-6) was significantly higher in the disease progression group; it decreased post-treatment, reflecting the negative sputum culture conversion.

CONCLUSION

Serum KL-6 level is associated with disease progression and treatment response. Longitudinal assessment combined with AFB smear status and presence of cavitary lesions may aid MAC-LD management.

Longitudinal changes in health-related quality of life according to clinical course among patients with non-tuberculous mycobacterial pulmonary disease: a prospective cohort study

BACKGROUND

Improvement in health-related quality of life (HRQL) has been suggested as an alternative treatment goal of non-tuberculous mycobacterial pulmonary disease (NTM-PD). This study was performed to elucidate the longitudinal changes in HRQL using St. George's Respiratory Questionnaire (SGRQ) among patients with NTM-PD according to their clinical course.

METHODS

Patients with NTM-PD who participated in Seoul National University Hospital's prospective NTM cohort were screened. Participants for whom the SGRQ score was estimated with the one-year interval for ≥ three times were included. The longitudinal trends of the SGRQ score were assessed. The impact of the clinical course on the change in the SGRQ score was elucidated using multilevel mixed-effects linear regression with a repeated-measures model.

RESULTS

In total, 114 patients were analyzed. During the median 5-year observation period, 53 patients started anti-mycobacterial treatment and 61 patients were observed without treatment. Among the treated patients, 24 (45.2%) achieved microbiological cure. Patients who required treatment eventually had worsening SGRQ scores with time compared with patients who could be observed without treatment (P < 0.001). In cured patients, the SGRQ score decreased from 33.9 at baseline to 20.8 at 1 year post-treatment (P < 0.001), 21.3 at 2 years (P < 0.001), and 17.6 at 3 years (P < 0.001). The SGRQ scores also decreased for 2 years of treatment in patients with NTM-PD that could not be cured, although this decrease did not last for 3 years of treatment.

CONCLUSION

Worsening HRQL scores were associated with the initiation of treatment and, in turn, treatment improved HRQL scores of patients with NTM-PD.

TRIAL REGISTRATION

This study was registered to the ClinicalTrials.gov (Identifier: NCT01616745 / registration date: June 12, 2012). The protocol was retrospectively registered.

Impact of prognostic nutritional index on outcomes in patients with Mycobacterium avium complex pulmonary disease

Onodera’s prognostic nutritional index (PNI) is useful in predicting prognosis of various diseases. But the usefulness of PNI in non-surgical patients has not been sufficiently proven yet. In patients with mycobacterium avium complex pulmonary disease (MAC-PD), malnutrition is an important factor that affects the quality of life and morbidity. Here, we aimed to evaluate whether PNI is related with clinical outcomes in MAC-PD patients. We examined 663 patients diagnosed with MAC-PD between May 2005 and November 2017. PNI score was calculated at the time of diagnosis and treatment initiation, and patients were divided into malnutrition and non-malnutrition groups according to a cut-off PNI score of 45. As the recommended duration of treatment for MAC-PD is 12 months following sputum conversion, treatment duration less than 12 months was defined as treatment intolerance. Survivals were compared with the log-rank test. Multivariate logistic regression and multivariate Cox proportional hazards models were used to estimate the odds ratio (OR) and hazards ratio (HR) for treatment intolerance and mortality, respectively. Of the 306 patients that received treatment, 193 received treatment longer than 12 months. In the multivariable logistic regression model, malnutrition at the time of treatment initiation was related with treatment intolerance (OR: 2.559, 95% confidence interval [CI]: 1.414–4.634, P = 0.002). Patients in the malnutrition group at the time of diagnosis exhibited lower survival (P<0.001) and malnutrition at the time of diagnosis was a significant risk for all-cause mortality (HR: 2.755, 95% CI: 1.610–4.475, P<0.001). Malnutrition, as defined by PNI, is an independent predictor for treatment intolerance and all-cause mortality in patients with MAC-PD.

Spontaneous sputum conversion and reversion in Mycobacterium abscessus complex lung disease

Background

We aim to investigate the rate of spontaneous sputum conversion and reversion in patients with Mycobacterium abscessus complex (MABC) lung disease.

Methods

Among 241 patients diagnosed with MABC lung disease between July 2012 and December 2018, 126 patients with persistent sputum positivity for ≥ 6 months without treatment were enrolled at a tertiary referral center in South Korea. Patients were subdivided into two groups, depending on whether or not treatment was initiated within 2 years of diagnosis. The rates of spontaneous sputum culture conversion and reversion was investigated in patients who did not receive treatment within 2 years.

Results

The mean age of 126 patients was 62.9 years. During a mean follow-up duration of 3.2 years, 33 (26.2%) patients received treatment within 2 years of diagnosis. Among the remaining 93 patients not receiving treatment within 2 years, spontaneous sputum conversion occurred in 24 (25.8%) patients during a mean follow-up duration of 3.7 years after diagnosis. No significant differences were observed in time to conversion between Mycobacterium abscessus and Mycobacterium massiliense lung diseases. The Cox regression analysis showed that malignancy as a comorbid disease and the lower number of lobes involved were independent predictors of spontaneous sputum conversion. After spontaneous sputum conversion, reversion occurred in 27.8% patients at a median of 18.2 months after conversion.

Conclusions

Among patients with MABC lung disease who did not receive treatment for at least 2 years after diagnosis, approximately one-fourth experienced spontaneous conversion. However, not a few patients experienced reversion after spontaneous conversion.

Nontuberculous mycobacteria in solid organ transplant

PURPOSE OF REVIEW

Nontuberculous mycobacteria (NTM) are emerging pathogens of concern especially in solid organ transplant candidates and recipients. This review aims to address diagnostic challenges, new and emerging treatment options, and infection prevention.

RECENT FINDINGS

The incidence of NTM infections in transplant candidates and recipients is rising. The infection prevalence of these environmental pathogens varies geographically by species with a coastal predominance. Although existing guidelines from the American Thoracic Society, Infectious Diseases Society of America, and British Thoracic Society provide recommendations for diagnosis and management, they do not fully address the subtle nuances and challenges faced in managing infections in immunocompromised transplant recipients. Evolving data on new therapeutic agents and their use in combination therapy will help individualize treatment regimens while limiting adverse effects and improving compliance. Use of combination β-lactams, avibactam, tedizolid, clofazimine, bedaquiline, liposomal amikacin, and ciprofloxacin for commonly isolated species such as Mycobacterium abscessus and Mycobacterium avium complex have proven effective.

SUMMARY

Further studies are needed to determine the incidence of NTM infection in a prospective, multicentric manner and evaluate the most promising synergistic treatment combinations in transplant recipients.

Protocol of a Nationwide Observational Study among Patients with Nontuberculous Mycobacterium Pulmonary Disease in South Korea (NTM-KOREA)

BACKGROUND

The burden of nontuberculous mycobacterial (NTM) pulmonary disease (PD) is increasing globally. To understand the treatment outcomes and prognosis of NTM-PD, a unified registry is needed. In this project, we aim to construct a multicenter prospective observational cohort with NTM-PD in South Korea (NTM-KOREA).

METHODS

The primary objective of this study is to analyze treatment outcomes according to the species. In addition, recurrence rate, adverse events, the impact of each drug on treatment outcomes as well as the impact of characteristics of mycobacteriology will be analyzed. The inclusion criteria for the study are as follows: fulfilling the criteria for NTM-PD having one of the following etiologic organisms: Mycobacterium avium complex, M. abscessus subspecies abscessus, M. abscessus subspecies massiliense, or M. kansasii; receiving the first treatment for NTM-PD after enrollment; age >20 years; and consenting to participate in the study. Seven institutions will participate in patient enrollment and about 500 patients are expected to be enrolled. Participants will be recruited from 1 March 2020 until 19 March 2024 and will be observed through 19 March 2029. During the follow-up period, participants' clinical course will be tracked and their clinical data as well as NTM isolates will be collected.

CONCLUSION

NTM-KOREA will be the first nationwide observational cohort for NTM-PD in South Korea. It will provide the information to optimize treatment modalities and will contribute to deeper understanding of the treatment outcomes and long-term prognosis of patients with NTM-PD in South Korea.

Treatment Outcomes after Discontinuation of Ethambutol due to Adverse Events in Mycobacterium avium Complex Lung Disease

BACKGROUND

Long-term administration of ethambutol (EMB) for Mycobacterium avium complex lung disease (MAC-LD) sometimes leads to permanent discontinuation of EMB due to various adverse events. This study aimed to investigate treatment outcomes after discontinuation of EMB.

METHODS

Among patients diagnosed with MAC-LD between January 2001 and December 2014, 508 patients whose treatment was initiated with standard regimen until May 2018 were enrolled at a tertiary referral center in Korea. Of these 508 patients, 60 (11.8%) discontinued EMB due to various adverse effects. Among these 60 patients, treatment outcomes were analyzed for 44 patients by comparing their outcomes with those of matched subjects who received the standard treatment regimen without EMB discontinuation.

RESULTS

The mean age of the 60 patients who discontinued EMB was 64.4 years. Ocular toxicity was the most common cause of discontinuation of EMB (75.0%, 45/60). The mean duration of EMB administration before its discontinuation was 7.0 ± 4.6 months. The treatment failure rate of the 44 patients with EMB discontinuation analyzed for treatment outcome was 29.6%, which was higher than that of the matched patients who received the standard regimen (18.3%), although the difference was not significant (P = 0.095). Of these 44 patients, EMB was substituted with later-generation fluoroquinolone in 23 patients, and the treatment failure rate of these 23 patients was significantly higher than that of the matched patients who received the standard regimen (39.1% vs. 19.3%, P = 0.045).

CONCLUSION

These findings suggest that treatment outcomes are unsatisfactory in patients with MAC-LD who discontinue EMB owing to adverse events. Notably, there was a statistically significant high failure rate in patients who were prescribed fluoroquinolone to replace EMB.

Outcome of shorter treatment duration in non-cavitary nodular bronchiectatic Mycobacterium avium complex lung disease

Background

The recommended treatment duration for non-cavitary nodular bronchiectatic (NC-NB) Mycobacterium avium complex (MAC) lung disease (LD) is at least 12 months after culture conversion, but evidence supporting this is limited. This study investigated whether treatment for less than 12 months after culture conversion is acceptable in terms of recurrence rate.

Methods

The study enrolled the patients diagnosed with NC-NB MAC LD between 2001 and 2014 at a tertiary referral center in South Korea who received the standard treatment for at least 9 months after culture conversion up to October 2018. The patients were divided into a shorter treatment group (9-11 months after culture conversion) and a standard treatment group (≥12 months).

Results

Of the 228 patients enrolled, 59 (25.9%) were treated for 9-11 months after culture conversion and 169 (74.1%) for ≥12 months. The mean treatment durations after culture conversion in the shorter and standard treatment groups were 11.1 and 13.8 months, respectively (P<0.001). During median follow-up durations after the completion of treatment of 56.5 and 55.9 months, respectively, the recurrence rates in the two groups were similar, at 39.0% (23/59) and 36.7% (62/169). There were also no significant differences between the groups in the 1-year and 3-year recurrence rates.

Conclusions

Post-conversion treatment shorter than the recommended duration may be adequate in terms of recurrence rate for patients with NC-NB MAC LD who receive the standard treatment for at least 9 months after culture conversion.

Real-life evaluation of clinical outcomes in patients undergoing treatment for non-tuberculous mycobacteria lung disease: A ten-year cohort study

Outcome recognition is a crucial step in the management of non-tuberculous mycobacteria lung disease (NTM-LD). In order to explore NTM-LD outcomes in a real-life setting, an observational, retrospective study enrolling consecutive adults who received treatment for NTM-LD in Milan, Italy, from 2007 to 2017 was conducted. Among 170 patients (68.2% females; median age: 68 years), NTM-LD was mainly due to M. avium complex (MAC) (71.2%), M. kansasii (9.4%) and M. xenopi (7.1%). Along a median follow-up of 31 months, adverse events occurred in 37.6% of the patients. Treatment outcomes of the entire study population included an unsuccessful outcome in 35.3% of the patients, including treatment halted in 13.5%, recurrence in 11.2%, re-infection in 5.3%, treatment failure in 4.1% and relapse in 1.2%. The main reason for treatment halted was drug intolerance. No differences were detected between patients with MAC-LD vs. those with other NTM-LD in terms of unsuccessful outcome in general (35.5% vs. 34.7%). A significantly higher prevalence of patients who underwent treatment halted was found in patients with NTM-LD other than MAC in comparison to patients with MAC-LD (22.4% vs. 9.9%, p = 0.030). One third of adults undergoing treatment for a NTM-LD experiences an unsuccessful outcome with adverse events and treatment discontinuation being major challenges in patients' management.

Incremental Shuttle Walk Distance as an Indicator for Functional Exercise Capacity of Pre-Surgical Patients with Nontuberculous Mycobacterial Lung Disease

The incidence of nontuberculous mycobacterial lung disease (NTMLD) is increasing worldwide, the number of lung surgeries is increasing accordingly. The disease is progressive and is characterized by exertional intolerance, respiratory dysfunctions, and impaired health-related quality of life (HRQOL). Treatment comprises multidrug antibiotic treatment combined with lung resection. The incremental shuttle walk distance (ISWD) is a standard tool for assessing the patients' tolerance to lung resection. The exertional tolerance, physical functions and HRQOL among pre-surgical patients with NTMLD are clinically important, but not fully studied yet from the viewpoint of physiotherapy. The purpose of this study was to explore the clinical significance of ISWD for assessing the exercise capacity of pre-surgical patients with NTMLD. For peripheral muscle evaluation, the strength of the quadriceps femoris muscle was measured. HRQOL was evaluated using scores of the St. George's Respiratory Questionnaire (SGRQ). Thirty-three patients (mean age 54.9 ± 13 years) were enrolled. The mean ISWD was 505 ± 134 m, shorter than the reference values (ISWD %predicted: 96 ± 27%). Regression analysis showed significant associations between ISWD and percent-predicted vital capacity (r = 0.38, p = 0.03) and percent quadriceps force/body weight (r = 0.54, p = 0.001). HRQOL assessed by SGRQ scores was correlated with ISWD (r < -0.4, p < 0.05). Multiple regression analysis showed that ISWD was significantly associated with leg muscle strength and with HRQOL. In conclusion, ISWD is useful to evaluate the exercise capacity among pre-surgical patients with NTMLD.