Determinants of recurrence after successful treatment of Mycobacterium avium complex lung disease

Treatment outcomes and relapse in patients with Mycobacterium avium-intracellulare complex pulmonary disease

The treatment responses and outcomes in patients with Mycobacterium avium-intracellulare complex pulmonary disease (MAC-PD) remain uncertain. This retrospective study was conducted in Taiwan between 2011 and 2020. A microbiological cure was defined as the requirement for a minimum of three consecutive negative cultures following culture conversion that continued until the completion of anti-MAC treatment. A total of 97 patients with MAC-PD were enrolled in this study. The sputum smear-negative conversion rate was 40% (19/47). Thirty (31%) patients achieved sputum culture-negative conversion rates within 3 years after treatment initiation. All patients with negative sputum culture conversion rates achieved microbiological cure. Patients treated with a macrolide + rifamycin + ethambutol (M + R + EMB)-based regimen had a higher microbiological cure rate than the other patients (39% vs 17%, P = 0.023). Patients with persistently positive sputum smears after 6 months of treatment had a lower microbiological cure rate than those with negative sputum smears (6% vs 44%, P < 0.001). Among 30 patients with microbiological cure, the median time from sputum culture conversion to treatment completion was 221.5 (0-483) days, and the 1-year relapse rate was 17%. Treatment with the M + R + EMB-based regimen was associated with a higher microbiological cure rate, and patients with persistently positive sputum smears after 6 months of treatment had a lower microbiological cure rate. IMPORTANCE The treatment responses and outcomes in patients with Mycobacterium avium-intracellulare complex pulmonary disease (MAC-PD) remain uncertain. In this study, patients with MAC-PD treated with a macrolide + rifamycin + ethambutol (M + R + EMB)-based regimen had a higher microbiological cure rate than those treated with other regimens. After 6 months of treatment, patients with persistently positive sputum smears had a lower microbiological cure rate than those with negative sputum smears. Among patients with microbiological cure, the median time from sputum culture conversion to treatment completion was 221.5 days (range, 0-483), and the 1-year relapse rate was 17%.

Outcomes of Adjunctive Surgery in Patients With Nontuberculous Mycobacterial Pulmonary Disease: A Systematic Review and Meta-analysis

BACKGROUND

The burden of nontuberculous mycobacterial pulmonary disease (NTM-PD) is increasing worldwide. Amidst the poor treatment success of antibiotic therapy, adjunctive surgery is gaining attention; however, discrepancies in reported outcomes exist.

RESEARCH QUESTION

What are the treatment outcomes and complications of patients with NTM-PD undergoing adjunctive surgery?

STUDY DESIGN AND METHODS

The MEDLINE, Embase, and Cochrane databases were searched for eligible studies before January 2022. Studies reporting the outcomes of adjunctive surgery in adult patients who satisfied the diagnostic criteria for NTM-PD were included. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guidelines. Data were extracted by two independent observers. Estimates of proportion were pooled using a random-effects model. Sputum mycobacterial culture negative conversion, recurrence, complications, and in-hospital mortality after surgery were primary outcomes that had been set before data collection began. Heterogeneity was evaluated by using the I² statistic, and publication bias was assessed by using funnel plots and the Egger test.

RESULTS

Fifteen of the 2,739 screened studies, with 1,071 patients, were assessed. The weighted proportion of postoperative sputum culture negative conversion was 93% (95% CI, 87%-97%), and recurrence was 9% (95% CI, 6%-14%) for a median follow-up of 34 months. The proportion of patients who experienced postoperative complications was 17% (95% CI, 13%-23%), and in-hospital mortality was 0% (95% CI, 0%-2%). Studies that performed multilobar lung resection in > 30% of the study population showed comparable rates of complications with studies that did not.

INTERPRETATION

Adjunctive surgery is an effective therapeutic option with acceptable rates of complications for selected patients with NTM-PD.

TRIAL REGISTRY

PROSPERO; No.: CRD42022310663; URL: https://www.crd.york.ac.uk/prospero/.

Old age is associated with worse treatment outcome and frequent adverse drug reaction in Mycobacterium avium complex pulmonary disease

Background

The number of patients with nontuberculous mycobacterial pulmonary disease (NTM-PD) is rapidly increasing globally, especially in the older population. However, there is a dearth of evidence regarding the impact of aging on the treatment outcomes of NTM-PD.

Methods

We analyzed consecutive patients who satisfied the diagnostic criteria for Mycobacterium avium complex (MAC)-PD and received antibiotic treatment between January 2009 and December 2020 at a tertiary referral hospital in Korea. The main outcomes were (1) long-term treatment success, defined by negative culture conversion for more than 12 months; and (2) adverse drug reactions (ADRs). Multivariable logistic regression model was used to evaluate the association between age and main outcomes.

Results

A total of 614 patients (median age, 65 years, interquartile range [IQR] 57–73 years; men, 35.3%) were included. Median treatment duration (530 days, IQR 290–678 days; P for trend < 0.001) and long-term treatment success (P for trend = 0.026) decreased, whereas ADRs (P for trend < 0.001) increased significantly with age. Multivariable analyses demonstrated that age ≥ 80 years was an independent factor associated with ADRs (adjusted odds ratio [aOR] 3.29; 95% confidence interval [CI] 1.05–10.28) and worse treatment outcome (aOR 0.42; 95% CI 0.19–0.91).

Conclusions

Aging is associated with worse treatment outcome and frequent ADRs of patients with MAC-PD. Individualized treatment with reduced-intensity may be a reasonable alternative for older adults.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-02063-2.

Low-dosage ethambutol, less than 12.5 mg/kg/day, does not worsen the clinical outcomes of pulmonary Mycobacterium avium and Mycobacterium intracellulare disease: a retrospective cohort study

OBJECTIVES

Multidrug chemotherapy is recommended for treating pulmonary Mycobacterium avium and Mycobacterium intracellulare disease. Although ethambutol has been demonstrated to inhibit macrolide resistance, the ethambutol dosage is sometimes decreased due to concerns about optic neuropathy. We aimed to assess whether lower ethambutol doses impact treatment outcomes.

METHODS

Patients treated over 12 months between 2016 and 2020 were collected retrospectively. Clinical outcomes, including negative culture conversion, microbiological cure, adverse events, resistance to macrolides, and recurrence, were compared according to daily ethambutol dosage.

RESULTS

Among 146 patients, 42 were treated with ethambutol dosages over 12.5 mg/kg/day, and 104 were treated with lower dosages. Negative culture conversion was achieved for 125 patients, and 90 patients achieved microbiological cure. Recurrence was identified in 16 patients who achieved microbiological cure. No macrolide resistance was observed, and no significant difference was observed in the percentage of negative culture conversion (P = 1.00) or microbiological cure (P = 0.67) between the high- and low-dosage ethambutol groups. Sputum smear positivity was associated with a lower adjusted odds ratio (aOR) of negative culture conversion (aOR: 0.48, 95% CI: 0.29-0.80). A lower aOR of microbiological cure was independently associated with sputum smear positivity (aOR: 0.52, 95% CI: 0.37-0.74) and with the use of an intermittent regimen (aOR: 0.60, 95% CI: 0.41-0.87). Daily ethambutol dosage was not identified as a prognostic factor for any of the outcomes. Optic neuropathy was observed in 7.1% of the high-dose ethambutol group and 1.0% of the low-dosage ethambutol group (P = 0.07).

CONCLUSION

An ethambutol dosage of 12.5 mg/kg/day or less in guideline-based chemotherapy may reduce optic neuropathy without worsening clinical outcomes.

Identification of the Target for a Transition Metal-α-Amino Acid Complex Antibiotic Against Mycobacterium smegmatis

Spontaneous mutants of Mycobacterium smegmatis strain mc²155 resistant to 1-PG (iridium-L-phenylglycine complex), an antimycobacterial antibiotic, were isolated. Based on the discovery that some 1-PG-resistant mutants (1-PG^R) were also resistant to high concentrations of clarithromycin (≥250 μg/ml), but no other anti-mycobacterial antibiotics, the 23S rRNA region spanning the peptidyl transferase domain was sequenced and mutations shown to be localized in the peptidyl transferase domain of the 23S rRNA gene. Measurements showed that 1-PG bound to ribosomes isolated from the 1-PG-sensitive parental strain, but the ribosome binding values for the 1-PG^R mutant reduced.

Redevelopment after spontaneous sputum conversion in noncavitary nodular bronchiectatic Mycobacterium avium complex lung disease

BACKGROUND

Although spontaneous sputum conversion can occur in noncavitary nodular bronchiectatic (NC-NB) Mycobacterium avium complex lung disease (MAC-LD), little is known about redevelopment after spontaneous conversion. We investigated the redevelopment phenomenon after spontaneous sputum conversion in patients with NC-NB MAC-LD.

MATERIAL AND METHODS

Among patients diagnosed with NC-NB MAC-LD between 2000 and 2013, 140 patients who experienced spontaneous sputum conversion, and whose follow-up duration after conversion was ≥6 months, were enrolled at a tertiary referral center in South Korea. Their medical records were retrospectively reviewed.

RESULTS

Of the 140 patients, 34 (24.3%) underwent redevelopment during the median follow-up period of 71.0 months (interquartile range [IQR], 58.8-87.5). Redevelopment occurred at a median interval of 25.0 months (IQR, 11.5-41.8) after spontaneous sputum conversion. The mean age of the 34 patients with redevelopment was 63.6 years, and 73.5% were women. No statistically significant differences in clinical characteristics were noted between the 34 patients with redevelopment and those with persistent conversion. Among the 34 patients with redevelopment, 6 received treatment at a median interval of 8 months (IQR, 1.5-16.8) after redevelopment. No significant differences in clinical characteristics were noted between the six treated and 28 untreated patients.

CONCLUSION

At least approximately 24% of patients with spontaneous sputum conversion in NC-NB MAC-LD had redevelopment, and a portion of them required treatment. These findings suggest that long-term follow-up is necessary for patients with NC-NB MAC-LD, even those who experience spontaneous sputum conversion.

Symptom Burden and Medication Use Among Patients with Nontuberculous Mycobacterial Lung Disease

Purpose

Respiratory diseases caused by nontuberculous mycobacteria (NTM) have become a significant concern for patients and health care providers. We aimed to compare symptoms experienced during the 2 week period, at a single point in time, by patients with NTM lung disease (NTMLD) who were currently on any medication to treat their NTMLD versus those not on any therapies.

Methods

We analyzed responses to a "Burden of NTM Survey" developed by the COPD Foundation. The study population included 266 individuals with NTMLD. Using adjusted penalized logistic regression models, we determined associations between the self-reported symptoms and the use of any medication to treat NTMLD.

Results

Based on available data, most respondents were aged 50 and older (95.1%), of female gender (93.1%), and had been living with NTMLD for more than 5 years (55.7%). Many respondents reported symptoms that bother them very often or daily. After adjustment for age and gender, duration of living with NTMLD, and other respiratory illnesses, patients on medication had significantly larger odds of reporting difficulty in walking 500 meters without stopping, difficulty in interacting with others, fatigue or lack of energy, feelings of sadness or depression related to illness, and shortness of breath, wheezing or other difficulties.

Conclusion

In this study, patients currently on any medication to treat their NTMLD reported more symptoms associated with their NTMLD. Further investigations are needed to explore whether increased symptoms are related to differences in disease severity and/or medication effects.

The impact of adjuvant surgical treatment of nontuberculous mycobacterial pulmonary disease on prognosis and outcome

BACKGROUND

Lung resection in patients with nontuberculous mycobacterial pulmonary disease (NTM-PD) has been reported to be associated with favorable outcomes. However, little is known regarding the risk and prognostic factors for refractory and recurrent cases. We aimed to evaluate the overall impact and benefit of adjuvant lung surgery by comparing NTM-PD patients who underwent adjuvant lung resection with those treated exclusively with antibiotics. We also investigated the efficacy of serum IgA antibody against glycopeptidolipid (GPL) core antigen (GPL core antibody) to monitor disease activity and predict the recurrence of disease after adjuvant lung resection.

METHODS

We retrospectively evaluated the clinical characteristics and surgical outcomes of 35 patients surgically treated for NTM-PD. Furthermore, we compared surgically treated patients and control patients treated exclusively with antibiotics who were matched statistically 1:1 using a propensity score calculated from age, sex, body mass index, and radiologic features of disease.

RESULTS

In the surgically treated patients, the median age was 58 (interquartile range, 47-65) years and 65.7% were female. Twenty-eight patients had Mycobacterium avium complex. Operations comprised four pneumonectomies, two bilobectomies, one bilobectomy plus segmentectomy, 17 lobectomies, two segmentectomies, and nine lobectomies plus segmentectomies. Postoperative complications occurred in seven patients (20%), there were no operative deaths, and 33 (94.3%) patients achieved negative sputum culture conversion. Refractory and recurrent cases were associated with remnant bronchiectasis, contralateral shadows, and positive acid-fast bacilli staining or culture. Of 28 statistically matched pairs, long-term sustained negative culture conversion was observed in 23 (82.2%) surgical group patients and in 14 (50.0%) non-surgical group patients (0.0438). The mortality rate was lower in the surgical group, but did not reach statistical significance (one in the surgical group and four in the non-surgical group, p = 0.3516). GPL core antibody was correlated with disease activity and recurrence.

CONCLUSIONS

NTM-PD patients who underwent adjuvant lung resection experienced overall favorable outcomes and achieved sputum culture conversion more frequently. Long-term mortality may have been reduced by this procedure, and the level of GPL core antibody was shown to be a good clinical indicator of disease activity after surgery.

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.

Long-Term Treatment Outcome of Progressive Mycobacterium Avium Complex Pulmonary Disease

BACKGROUND

Multidrug therapy is essential for preventing respiratory failure in patients with highly progressive Mycobacterium avium complex pulmonary disease (MAC-PD). However, the prognosis and long-term outcome following combination therapy is poorly understood.

METHODS

We retrospectively evaluated the clinical characteristics and long-term outcomes in patients with chemo-naïve progressive MAC-PD, hospitalized for first-line multidrug therapy.

RESULTS

Among 125 patients, 86 (68.8%) received standardized treatment (rifampicin, ethambutol, clarithromycin), 25 (20.0%) received a fluoroquinolone (FQ)-containing regimen, and 53 (42.4%) received aminoglycoside injection. The sputum conversion rate was 80.0%, and was independently associated with standardized treatment. The incidence of refractory disease (45.6%) was independently and negatively associated with standardized regimen and aminoglycoside use. Choice of an FQ-containing regimen was not associated with positive outcome. Clarithromycin resistance occurred in 16.8% and was independently associated with refractory disease. MAC-PD-associated death occurred in 3.3% of patients with non-cavitary nodular bronchiectasis (NB) and 21.3% with cavitary MAC-PD over a median follow-up period of 56.4 months. The rates of MAC-PD-associated death were comparable between cavitary-NB and fibrocavitary disease. Concurrent chronic pulmonary aspergillosis (CPA) occurred in 13 (17.3%) patients with cavitary MAC-PD, and age, diabetes mellitus, and CPA were independent risk factors for mortality.

CONCLUSIONS

Standardized intensive multidrug treatment reduces disease progression and persistence in progressive MAC-PD. Cavitary NB may differ from, rather than being just an advanced stage of, non-cavitary NB. The high incidence and significant mortality of CPA in cavitary MAC-PD highlight the need for early diagnosis and treatment.

Development of Macrolide Resistance and Reinfection in Refractory Mycobacterium avium Complex Lung Disease

RATIONALE

Patients with refractory Mycobacterium avium complex lung disease (MAC-LD) undergo long-term macrolide therapy, but macrolide resistance develops infrequently.

OBJECTIVES

The aim of this study was to determine whether reinfection was a factor in the low incidence of macrolide resistance in patients with refractory MAC-LD.

METHODS

Among 481 patients with treatment-naive MAC-LD who started antibiotic treatment between January 2002 and December 2013, we identified 72 patients with refractory disease, characterized by persistently positive sputum cultures despite ≥12 months of treatment. Molecular analyses of the 23S ribosomal RNA gene responsible for macrolide resistance and serial mycobacterial genotyping were performed using stored MAC isolates.

MEASUREMENTS AND MAIN RESULTS

The median duration of treatment was 32 months (interquartile range, 24-41 mo) in 72 patients. After treatment for a median of 33 months (interquartile range, 21-44 mo), macrolide resistance developed in 16 (22%) patients. Molecular analysis of isolates from 15 patients revealed that 80% (12 of 15) had a point mutation at position 2,058 or 2,059 of the 23S ribosomal RNA gene. Of the 49 patients who had stored pre- and post-treatment isolates, mycobacterial genotyping revealed that reinfection by new MAC strains occurred in 36 (73%) patients. New MAC strains were found in 24 (49%) patients, and mixed infections with original and new strains occurred in 12 (24%) patients. Only 13 (27%) patients had persistent infections with their original MAC strains.

CONCLUSIONS

Refractory MAC-LD is commonly caused by reinfection with new strains rather than persistence of the original strain, which may explain the infrequent development of macrolide resistance in refractory MAC-LD. Clinical trial registered with www.clinicaltrials.gov (NCT00970801).

Long-term natural history of non-cavitary nodular bronchiectatic nontuberculous mycobacterial pulmonary disease

BACKGROUND

Information about the natural history of nontuberculous mycobacterial pulmonary disease (NTM-PD) is limited. The purpose of this study was to evaluate the long-term natural history of non-cavitary nodular bronchiectatic NTM-PD and the factors associated with treatment initiation and the frequency of spontaneous sputum culture conversion after diagnosis of NTM-PD.

METHODS

We evaluated 1,021 patients with newly diagnosed non-cavitary nodular bronchiectatic NTM-PD caused by Mycobacterium avium complex or M. abscessus between 2003 and 2013.

RESULTS

Of 1,021 patients, 562 (55%) initiated antibiotic treatment and 459 (45%) did not. Young age (adjusted hazard ratio [aHR] = 0.99; 95% confidence interval [CI] = 0.98-0.99), low body mass index (aHR = 0.96; 95% CI = 0.93-0.99), previous history of tuberculosis (aHR = 1.23; 95% CI = 1.01-1.50), respiratory complaints such as cough (aHR = 1.36; 95% CI = 1.05-1.75) and sputum production (aHR = 1.47; 95% CI = 1.13-1.91), and high number of involved lobes on high-resolution computed tomography (aHR = 1.22; 95% CI = 1.14-1.31) were associated with treatment initiation. Of 459 patients who did not initiate treatment, 157 (34%) showed spontaneous sputum culture conversion. None of the clinical factors was associated with spontaneous conversion. After spontaneous culture conversion, 26 of 157 (17%) showed redeveloped NTM-PD caused by a species different from the original species.

CONCLUSIONS

The natural history of non-cavitary nodular bronchiectatic NTM-PD is variable. After diagnosis, the decision to initiate antibiotic therapy should be individualized based on consideration of the risk factors for disease progression. However, for patients who do not start antibiotic therapy, continuous and lifetime follow-up is recommended to manage underlying bronchiectasis and the possibility of late progression of NTM-PD.

Clinical characteristics and early outcomes of patients newly diagnosed with pulmonary Mycobacterium avium complex disease

BACKGROUND

The incidence of asymptomatic pulmonary Mycobacterium avium complex (MAC) disease appears to be increasing. This study aimed to determine the clinical characteristics and examine early outcomes of patients newly diagnosed with MAC disease.

METHODS

We retrospectively reviewed the medical records of all 184 patients newly diagnosed with MAC disease between April 2013 and March 2015 at our hospital. Culture conversion, defined as at least two consecutive negative cultures, was used as the early outcome measure.

RESULTS

Of 184 patients, 45 were male and 139 were female, with a mean age of 70 years. Abnormal chest shadow found during an annual health check-up (58 patients) or incidentally during visits for other diseases (72 patients), was the major reason for referral to hospital, typically with no symptoms. Anti-MAC IgA antibody was positive in 64.5% of patients, and the positive rate was associated with the extent of lesions. Clarithromycin-based multi-drug chemotherapy was initiated in 111 patients. Culture conversion was achieved in 61 of 82 (74.4%) patients who were able to continue multi-drug chemotherapy. Patients who achieved culture conversion were more likely to be younger, female, and have a lower smear grade and nodular-bronchiectatic type. Multivariate logistic regression analysis identified patient age and smear grade as predictive variables.

CONCLUSIONS

Abnormal chest shadow found during health check-up was the major reason for hospital visits, and most were asymptomatic. Culture conversion was achieved in three-fourths of patients treated, and was associated with age and smear grade, supporting early intervention at a younger age.

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

Mycobacterium avium complex (MAC) and M. abscessus complex (MABC) comprise the two most important human pathogen groups causing nontuberculous mycobacterial lung disease (NTM-LD). However, there are limited data regarding NTM-LD caused by mixed NTM infections. This study aimed to evaluate the clinical characteristics and treatment outcomes in patients with NTM-LD caused by mixed infection with these two major NTM pathogen groups. Seventy-one consecutive patients who had been diagnosed with NTM-LD caused by mixed infection with MAC (M. avium or M. intracellulare) and MABC (M. abscessus or M. massiliense) between January 2010 and December 2015 were identified. Nearly all patients (96%) had the nodular bronchiectatic form of NTM-LD. Mixed infection with MAC and M. massiliense (n = 47, 66%) was more common than mixed infection with MAC and M. abscessus (n = 24, 34%), and among the 43 (61%) patients who were treated for NTM-LD for more than 12 months, sputum culture conversion rates were significantly lower in patients infected with MAC and M. abscessus (25% [3/12]) than in patients infected with MAC and M. massiliense (61% [19/31, P = 0.033]). Additionally, M. massiliense and M. abscessus showed marked differences in clarithromycin susceptibility (90% versus 6%, P < 0.001). Of the 23 patients who successfully completed treatment, 11 (48%) redeveloped NTM lung disease, with mycobacterial genotyping results indicating that the majority of cases were due to reinfection. Precise identification of etiologic NTM organisms could help predict treatment outcomes in patients with NTM-LD due to mixed infections.

Long-term Outcome of Pulmonary Resection for Nontuberculous Mycobacterial Pulmonary Disease

Background

Pulmonary resection along with multiple antimicrobial therapy has produced favorable outcomes at a few centers. However, little is known regarding the risk factors for long-term survival and microbiological recurrence after pulmonary resection for nontuberculous mycobacterial pulmonary disease (NTMPD). We evaluated the long-term outcomes of pulmonary resection, including microbiological recurrence and survival.

Methods

This retrospective cohort study included 125 patients (median age, 60 years) with NTMPD treated by pulmonary resection at two referral centers between January 1994 and August 2015.

Results

Postoperative complications occurred in 27 patients (22%). The complication rate after pneumonectomy was significantly higher than those after other types of pulmonary resection (odds ratio, 4.1; 95% confidence interval [CI], 1.6-10.3; P = .005). The median follow-up period was 7.1 years. While 19 patients experienced microbiological recurrence, 26 died. Multivariate analysis revealed pneumonectomy (adjusted hazard ratio [aHR], 0.12; 95% CI, .007-.66; P = .0098) and cavitary lesions after surgery (aHR, 6.73; 95% CI, 1.68-22.7; P = .0095) to be predictors of microbiological recurrence and old age (aHR, 1.06; 95% CI, 1.01-1.13; P = .016), low body mass index (BMI; aHR for every 1-kg/m2 increase, 0.72; 95% CI, .60-.85; P < .0001), pneumonectomy (aHR, 4.38; 95% CI, 1.78-11.3; P = .014), and remnant cavitary lesions (aHR, 3.53; 95% CI, 1.35-9.57; P = .011) to be predictors of poor prognosis.

Conclusions

Patients who could benefit from pulmonary resection should be carefully selected considering age, BMI, remnant lesions after surgery, and type of pulmonary resection.

Intermittent Antibiotic Therapy for Recurrent Nodular Bronchiectatic Mycobacterium avium Complex Lung Disease

Intermittent, three-times-weekly oral antibiotic therapy is recommended for the initial treatment of noncavitary nodular bronchiectatic (NB) Mycobacterium avium complex (MAC) lung disease. However, intermittent therapy is not recommended for patients who have been previously treated. We evaluated 53 patients with recurrent noncavitary NB MAC lung disease who underwent antibiotic treatment for ≥12 months with daily therapy (n = 26) or intermittent therapy (n = 27) between January 2008 and December 2015. Baseline characteristics were comparable between daily therapy and intermittent therapy groups. Sputum culture conversion rates did not differ between daily therapy (21/26, 81%) and intermittent therapy (22/27, 82%) groups. Compared to the etiologic organism at the time of previous treatment, recurrent MAC lung disease was caused by the same MAC species in 38 patients (72%) and by a different MAC species in 15 patients (28%). Genotype analysis in patients with sequenced paired isolates revealed that 86% (12/14) of cases with same species recurrence were due to reinfection with a new MAC genotype. In conclusion, most recurrent noncavitary NB MAC lung disease cases were caused by reinfection rather than relapse. Intermittent antibiotic therapy is a reasonable treatment strategy for recurrent noncavitary NB MAC lung disease.

Natural course of the nodular bronchiectatic form of Mycobacterium Avium complex lung disease: Long-term radiologic change without treatment

BACKGROUND/PURPOSE

Although the incidence of Mycobacterium avium complex (MAC) lung disease is increasing, the long-term natural course of the nodular bronchiectatic form of MAC lung disease is not well described. The objective of our study is to evaluate long-term radiologic changes in untreated MAC lung disease by analyzing serial chest computed tomography (CT) scan findings.

METHODS

Of 104 patients with MAC lung disease, we selected 40 untreated nodular bronchiectatic MAC patients who underwent serial chest CTs without treatment for at least four years (mean = 6.23 years). Majority of patients have minimal symptoms. Two chest radiologists retrospectively reviewed initial and final chest CT scans. Each chest CT scan was scored for presence and extent of bronchiectasis, cellular bronchiolitis, consolidation, cavity, and nodule (maximum score: 30).

RESULTS

Of 40 patients, 39 (97.5%) experienced a significant increase in overall CT score (overall difference = 4.89, p<0.001). On repeated measure analysis of variance analysis, cavity yielded the largest increase compared with cellular bronchiolitis (p = 0.013), nodule (p<0.001), and consolidation (p = 0.004). However, there was no significant difference in mean score change between cavity and bronchiectasis (p = 0.073). In analysis between radiologic parameters and the absolute number of involved segments, bronchiectasis showed most significant change compared with nodule (p<0.001) and consolidation (p<0.001).

CONCLUSIONS

Most untreated nodular bronchiectatic MAC lung disease cases showed radiologic deterioration over long-term observation periods when we compared serial chest CT scans. Careful monitoring of MAC lung disease with serial chest CT scan can be beneficial in these untreated patients.

Diagnosis and Treatment of Nontuberculous Mycobacterial Lung Disease

Nontuberculous mycobacteria (NTM) are ubiquitous organisms; their isolation from clinical specimens does not always indicate clinical disease. The incidence of NTM lung diseases has been increasing worldwide. Although the geographic diversity of NTM species is well known, Mycobacterium avium complex (MAC), M. abscessus complex (MABC), and M. kansasii are the most commonly encountered and important etiologic organisms. Two distinct types of NTM lung diseases have been reported, namely fibrocavitary and nodular bronchiectatic forms. For laboratory diagnosis of NTM lung diseases, both liquid and solid media cultures and species-level identification are strongly recommended to enhance growth detection and determine the clinical relevance of isolates. Treatment for NTM lung diseases consists of a multidrug regimen and a long course of therapy, lasting more than 12 months after negative sputum conversion. For MAC lung disease, several new macrolide-based regimens are now recommended. For nodular bronchiectatic forms of MAC lung diseases, an intermittent three-time-weekly regimen produces outcomes similar to those of daily therapy. Treatment of MABC lung disease is very difficult, requiring long-term use of parenteral agents in combination with new macrolides. Treatment outcomes are much better for M. massiliense lung disease than for M. abscessus lung disease. Thus, precise identification of species in MABC infection is needed for the prediction of antibiotic response. Likewise, increased efforts to improve treatment outcomes and develop new agents for NTM lung disease are needed.

Antibiotic treatment for nontuberculous mycobacterial lung disease

Pulmonary infections are the most frequent diseases caused by nontuberculous mycobacteria (NTM). Common causative organisms of pulmonary infection are slowly growing mycobacteria including Mycobacterium avium complex and Mycobacterium kansasii, and rapidly growing mycobacteria including Mycobacterium abscessus complex. Clinical concern has been raised over the increasing incidence of NTM lung disease combined with the poor treatment outcomes of these chronic infectious diseases. Since treatment guidelines of the American Thoracic Society/Infectious Disease Society of America were published in 2007 there have been continuous efforts to improve the outcomes of NTM lung disease, albeit slowly and with limitations. Here, we focus on recent advances in the antibiotic treatment of NTM lung disease.