Usefulness of bronchial lavage for the diagnosis of pulmonary disease caused by Mycobacterium avium-intracellulare complex (MAC) infection

Diagnostic Criteria and the Decision to Treat Nontuberculous Mycobacterial Pulmonary Disease

The diagnosis of nontuberculous mycobacterial (NTM) pulmonary disease is based on three criteria: patient's symptoms, radiographic findings, and microbiologic results. The microbiologic criterion is the most complicated because it requires more than one positive sputum acid-fast bacilli culture. Clinicians are challenged to apply the diagnostic criteria in the context of variable patient symptoms, NTM pathogenicity, and host susceptibility. The decision to treat NTM pulmonary disease entails assessment of the risks and benefits of therapy and the patient's wishes and ability to receive treatment.

Evaluation of a novel ELISA test using synthetic mycolic acid antigens for serodiagnosis of non-tuberculous mycobacterial (NTM) infections

The diagnosis of non-tuberculous mycobacteria (NTM) is a particular challenge in people with cystic fibrosis. Current standard diagnostic approaches rely on serial sputum culture, which is resource demanding, dependent on patient expectoration and may be compromised by excessive decontamination, conventional bacterial overgrowth and masking by concomitant oral and nebulised antibiotics. An alternative rapid, reliable and inexpensive diagnostic method is therefore urgently needed. Serum of patients with Mycobacterium abscessus infection and chronic suppurative lung disease without NTM infection was tested against an array of novel synthetic mycolic acids, identical or similar to natural components of mycobacterial cell walls, and glycopeptidolipid (GPL)-core antigen, which has previously been investigated in Mycobacterium avium pulmonary infection. Diagnostic accuracy of individual antigens and combination of various antigens were calculated. An ELISA using individual trehalose dimycolates and GPL-core antigen was able to effectively distinguish serum from infected and non-infected individuals with a specificity of 88% and a sensitivity of up to 88%, which increased to 88% sensitivity and 93% specificity by combining several antigens in the test. These results suggest synthetic mycolic acid antigens, used individually or in combination with GPL-core antigen could be successfully used to distinguish patients with M. abscessus infection from disease controls.

Detection of Mycobacterium avium-intracellulare Complex (MAC) by Bronchial Lavage and the Relationship with Titers of Anti-Glycopeptidolipid-Core IgA Antibodies to MAC in Patients with Pulmonary MAC Disease

Background

Higher rates of diagnosis of pulmonary Mycobacterium avium-intracellulare complex (MAC) disease by bronchoscopy (BS) in patients who could not diagnose by sputum cultures have been suggested, but the detailed utility of BS, especially in combination with anti-glycopeptidolipid-core IgA antibodies (anti-MAC Ab), is still unclear.

Methods

A total of 111 patients at our hospital with suspected MAC who underwent BS because they were sputum-negative from April 2018 to March 2022 were analyzed prospectively. These patients were also divided into two groups, anti-MAC Ab-positive and anti-MAC Ab-negative, and compared.

Results

A total of 111 patients underwent BS, though 95 (38.0%) of 250 enrolled patients were sputum smear/culture-positive. The age of the 111 patients was 69.14 (31.0-89.0) years, and 90 (81.0%) were female; 69 (62.2%) of 111 patients were either smear-positive (n = 42, 37.8%) or culture-positive (n = 27, 24.3%) by BS. Of the total 111 patients, 69 (62.2%) were anti-MAC Ab-positive and 57 (82.6%) of 69 patients were also positive by BS. In contrast, only 12 (28.6%) of the 42 anti-MAC Ab-negative patients were positive by BS. The sensitivity and specificity of anti-MAC Ab for positive by BS were 82.6% and 71.4%, respectively, and the area under the curve (AUC) on receiver-operating characteristic (ROC) curve analysis was 0.807.

Conclusion

BS and anti-MAC Ab showed similar usefulness to confirm the diagnosis in patients who could not be diagnosed by sputum examination, but pulmonary MAC disease was strongly suspected based on chest radiography/CT findings. These two examinations were correlated, and their combination appeared to provide more accurate diagnosis and earlier therapy.

Efficacy of three sputum specimens for the diagnosis of Mycobacterium avium complex pulmonary disease

BACKGROUND

In Mycobacterium avium complex pulmonary disease (MAC-PD), diagnosis requires a positive culture from at least two separate expectorated sputum specimens. The optimal number of sputum examinations remains unclear.

OBJECTIVE

This study sought to elucidate the diagnostic yield of acid-fast bacilli in MAC-PD using 3 sputum specimens and to clarify the clinical characteristics of patients with MAC-PD diagnosed using 3 sputum specimens. Furthermore, we investigated the correlation between increased number of sputum specimens and diagnostic yield.

METHODS

We reviewed the medical records of 139 patients with MAC-PD diagnosed at Toho University Omori Medical Center for whom at least three sputum specimens were examined before treatment from November 2014 through June 2021. Patients were classified into the 3-sputum diagnosed and the non-3 sputum diagnosed groups based on diagnostic procedure; clinical and radiological characteristics were compared. We also assessed diagnostic yield with the increased number of sputum specimens.

RESULTS

Diagnostic yield with 3 sputum specimens was 16.5% (23/139). The 3-sputum diagnosed group had a lower body mass index [18.6(17-19.5) vs. 19.5(18-21.5); p = 0.014], and higher chest CT score [9(6.5-13) vs. 6(4-9); p = 0.011] including cavitary lesions (39.1% vs. 19%; p = 0.037) compared with the non-3 sputum diagnosed group. When the number of sputum specimens was increased to 6, the diagnostic yield increased to 23.7% (33/139).

CONCLUSION

Diagnostic yield with 3 sputum specimens was 16.5%. Patients diagnosed using 3 sputum specimens had more severe chest CT findings including cavitary lesions. Increasing the number of sputum specimens to 6 improved diagnostic yield by 7.2%.

Bronchoscopy for the diagnosis of nontuberculous mycobacterial pulmonary disease: Specificity and diagnostic yield in a retrospective cohort study

BACKGROUND

Bronchoscopy is a recognized method for obtaining specimens for the diagnosis of nontuberculous mycobacterial pulmonary disease (NTM-PD). However, its diagnostic properties remain to be elucidated. The aim of this study was to determine the specificity of bronchoscopy for the diagnosis of NTM-PD, and to examine the diagnostic yield of bronchoscopy for detecting nontuberculous mycobacteria (NTM) when patients cannot expectorate sputum with NTM.

METHODS

This retrospective cohort study included 2657 patients who underwent bronchoscopy and mycobacterial culture between January 2004 and June 2018 in a tertiary care center in Tokyo, Japan. To examine the specificity of bronchoscopy, the first cohort comprised patients who underwent bronchoscopy for the diagnosis of lung cancer and mycobacterial culture. To investigate the diagnostic yield, patients with nodular bronchiectasis who underwent bronchoscopy for the diagnosis of NTM-PD were enrolled into the second cohort.

RESULTS

In total, 919 patients were diagnosed with lung cancer, 19 patients showed positive culture for NTM, and 14 patients showed findings for NTM-PD. Accordingly, the specificity was calculated as 900/905 (99.4%). In addition, NTM-PD was suspected before bronchoscopy in 199 patients; the diagnostic yield was 105/199 (52.8%). Four factors were associated with NTM-PD: upper lobe examination, absence of specific bacteria, absence of connective tissue disease, and a higher total computed tomography score.

CONCLUSIONS

Bronchoscopy has a high specificity for the diagnosis of NTM-PD. In addition, even when NTM is undetected in sputum, bronchoscopy may detect mycobacteria in approximately half of the patients suspected of having NTM-PD.

Usefulness of Post-bronchoscopy Sputum Culture for Diagnosis of Nontuberculous Mycobacterial Pulmonary Disease

BACKGROUND

Bronchoscopy is recommended for patients with suspected nontuberculous mycobacterial pulmonary disease (NTM-PD) whose sputum culture results are consistently negative or from whom adequate sputum samples cannot be obtained. Post-bronchoscopy sputum (PBS) collection is recommended for patients with suspected tuberculosis who undergo bronchoscopy. However, it remains unclear whether PBS collection can increase the diagnostic yield of NTM-PD.

METHODS

Patients with suspected NTM-PD who underwent diagnostic bronchoscopy from January 1, 2017 to June 30, 2020 at the Seoul National University Hospital were included in the study. They were divided into the sputum culture-negative and scanty sputum groups. The results of mycobacterial cultures from bronchial washing specimens and PBS were compared between these groups.

RESULTS

In total, 141 patients were included in the study; there were 39 and 102 patients in the sputum culture-negative and scanty sputum groups, respectively. Nontuberculous mycobacteria were cultured from bronchial washing specimens collected from 38.3% (54/141) of all patients (30.7% [12/39] patients in the sputum culture-negative group and 41.2% [42/102] patients in the scanty sputum group; P = 0.345). Nontuberculous mycobacteria were exclusively cultured from PBS collected from 3.5% (5/141) of all patients (7.7% [3/39] patients in the sputum culture-negative group and 2.0% [2/102] patients in the scanty sputum group; P = 0.255).

CONCLUSIONS

Additional PBS collection improved diagnostic yield marginally in patients with suspected NTM-PD who undergo bronchoscopy.

Establishment and validation of a predictive model for nontuberculous mycobacterial infections in acid-fast bacilli smear-positive patients

INTRODUCTION

Nontuberculous mycobacteria (NTM) and pulmonary tuberculosis (PTB) are difficult to distinguish in initial acid-fast bacilli (AFB) smear-positive patients.

OBJECTIVES

Establish a predictive model to identify more effectively NTM infections in initial AFB patients.

METHODS

Consecutive AFB smear-positive patients in the Respiratory Department of Shanghai Pulmonary Hospital from January 2019 to February 2020 were retrospectively analysed. A multivariate regression was used to determine the independent risk factors for NTM. A receiver operating characteristic (ROC) curve was used to determine the model's predictive discrimination. The model was validated internally by a calibration curve and externally for consecutive AFB smear-positive patients from March to June 2020 in this institution.

RESULTS

Presenting with haemoptysis, bronchiectasis, a negative QuantiFERON tuberculosis (QFT) test and being female were characteristics significantly more common in patients with NTM (P ≤ 0.001), when compared with PTB. The involvement of right middle lobe, left lingual lobe and cystic change was more commonly seen on chest high-resolution computed tomography (HRCT) in patients with NTM (P < 0.05), compared with PTB. Multivariate regression showed female, bronchiectasis, negative test for QFT and right middle lobe lesion were independent risk factors for NTM (P < 0.05). A ROC curve showed a sensitivity and specificity of 85.9% and 93.4%, respectively, and the area under the curve (AUC) was 0.963. Moreover, internal and external validation both confirmed the effectiveness of the model.

CONCLUSIONS

The predictive model would be useful for early differential diagnosis of NTM in initial AFB smear-positive patients.

Bronchial Brushing and Diagnosis of Pulmonary Nontuberculous Mycobacteria Infection

BACKGROUND

The optimal bronchoscopy procedure for diagnosis of pulmonary nontuberculous mycobacteria (NTM) infection is unclear.

OBJECTIVE

This study investigated the usefulness of bronchial brushing in bronchoscopy for diagnosis of pulmonary NTM infection in patients with suspected NTM lung disease and nodular bronchiectasis on chest computed tomography (CT) images.

METHODS

Bronchoscopy was prospectively performed for 69 patients with clinically suspected pulmonary NTM infection on chest CT from December 2017 through December 2019. Before and after bronchial brushing, bronchial washing was performed with 20 or 40 mL of normal sterile saline at the same segmental or subsegmental bronchi. Before and after bronchial brushing, samples of the washing fluid (pre- and postbrushing samples) and brush deposits (brush samples) were obtained and cultured separately.

RESULTS

NTM was detected in 37 of the 69 (53.6%) patients (Mycobacterium avium in 27, Mycobacterium intracellulare in 7, M. abscessus in 2, and M. kansasii in 2). NTM was detected in 34 (49.3%) prebrushing samples, in 27 (39.1%) postbrushing samples, and in 20 (29.0%) brush samples from the 69 patients. In 2 (2.9%) patients, NTM was detected only in postbrushing samples; in 1 (1.4%) patient, NTM was detected only in a brush sample. As compared with bronchial washing only, additional bronchial brushing increased the NTM culture-positive rate by 4.3% (3/69). Bronchial brushing caused bleeding, requiring hemostasis in 5 (7.2%) patients.

CONCLUSION

Additional bronchial brushing increased the NTM culture-positive rate by only 4.3% (3/69), as compared with bronchial washing alone. Thus, the usefulness of brushing appears to be limited.

Prognosis of nontuberculous mycobacterial pulmonary disease according to the method of microbiologic diagnosis

Microbiological criteria for nontuberculous mycobacterial pulmonary disease (NTM-PD) require cultures from two separate sputum or one non-sputum specimen. However, there is limited data on the progression of NTM-PD following non-sputum culture-based diagnosis. We compared the disease progression of NTM-PD diagnosed with non-sputum vs sputum cultures. We included 833 patients and divided them into sputum NTM isolation (n = 123), sputum NTM-PD (n = 558), and non-sputum NTM-PD groups (n = 152). Disease progression, defined as radiographic aggravation and therapy initiation, was compared between groups. The median observation time was 60.5 months (interquartile range, 31.4-96.0). The non-sputum NTM-PD group showed longer treatment-free survival (log-rank test; p = 0.009) and lower risk of treatment (adjusted hazard ratio [aHR] of sputum NTM-PD group, 1.36; 95% confidence interval (CI), 1.01-1.84) than the sputum NTM-PD group. The non-sputum NTM-PD group showed longer radiographic aggravation-free survival (Log-rank test; p = 0.015) and lower risk of radiographic aggravation (aHR of sputum NTM-PD group, 1.52; 95% CI, 1.06-2.19) than the sputum NTM-PD group. NTM-PD diagnosed using methods other than sputum culture showed a low risk of disease progression and progressed slower than NTM-PD diagnosed from a sputum culture. NTM-PD diagnosed using methods other than sputum culture may be a mild disease, not equivalent to NTM-PD diagnosed from sputum culture.

Diagnosing MonoMAC Syndrome in GATA2 Germline Mutated Myelodysplastic Syndrome via Next-Generation Sequencing in a Patient with Refractory and Complex Infection: Case Report and Literature Review

Monocytopenia and mycobacterial infection (MonoMAC) syndrome is a rare disease. Herein, we reported a 65-year-old Asian woman, previously diagnosed with myelodysplastic syndrome (MDS), suffering from recurrent pneumonia, intermittent fever, fatigue, and chest tightness lasting for five months. She was ultimately diagnosed with MonoMAC syndrome with Mycobacterium kansasii (M. kansasii) infection and GATA2 mutation through metagenomic generation sequencing (mNGS) of peripheral blood specimen, for which she was given anti-NTM therapy. Her situation significantly improved within 2 weeks of therapy. We discussed the clinical features, genetic characteristic, and prognosis of this disorder, aiming to further elucidate this rare syndrome. For MDS/AML patient with recurrent mixed infection and pancytopenia (especially with monocyte absence), MonoMAC syndrome should be highly suspected, and germline mutation and pathogen sequencing should be performed.

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.

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.

Clinical relevance and diagnosis of nontuberculous mycobacterial pulmonary disease in populations at risk

The lungs are the most common disease site of nontuberculous mycobacteria (NTM). However, the isolation of NTM in a respiratory specimen does not indicate lung disease (LD). Differentiation between NTM colonization and NTM-LD remains challenging. In this brief review, we summarize the clinical impact of NTM-LD on morbidity and mortality in high-risk populations. The diagnosis criteria for NTM-LD-including clinical features, radiological presentations, and microbiological evidence-are also reviewed, according to the latest American Thoracic Society (ATS)/Infectious Disease Society of America (IDSA) guideline and the British Thoracic Society (BTS) guideline. However, the diagnosis of NTM-LD does not necessitate the initiation of anti-NTM treatment. Both environmental, host, and bacterial factors should be considered to identify patients that require NTM-LD treatment.

Non-tuberculous mycobacterial pulmonary disease

Nontuberculous mycobacterial pulmonary disease (NTM-PD) is a challenging infection which is becoming increasingly prevalent, particularly in the elderly, for reasons which are unknown. While underlying lung disease is a well-established risk factor for NTM-PD, it may also occur in apparently healthy individuals. No single common genetic or immunological defect has been identified in this group, and it is likely that multiple pathways contribute towards host susceptibility to NTM-PD which further interact with environmental and microbiological factors leading to the development of disease.The diagnosis of NTM-PD relies on the integration of clinical, radiological and microbiological results. The clinical course of NTM-PD is heterogeneous, with some patients remaining stable without the need for treatment and others developing refractory disease associated with considerable mortality and morbidity. Treatment regimens are based on the identity of the isolated species, drug sensitivity testing (for some agents) and the severity of disease. Multiple antibiotics are typically required for prolonged periods of time and treatment is frequently poorly tolerated. Surgery may be beneficial in selected cases. In some circumstances cure may not be attainable and there is a pressing need for better regimens to treat refractory and drug-resistant NTM-PD.This review summarises current knowledge on the epidemiology, aetiology and diagnosis of NTM-PD and discusses the treatment of two of the most clinically significant species, the M. avium and M. abscessus complexes, with a focus on refractory disease and novel therapies.

Nontuberculous mycobacterial pulmonary disease diagnosed by two methods: a prospective cohort study

Background

Microbiological criteria for diagnosing nontuberculous mycobacterial pulmonary disease (NTM-PD) include positive culture results from at least two separately expectorated sputum specimens or one bronchial washing or lavage. However, the clinical similarities and differences between patients diagnosed by these two methods remain unclear. We compared clinical features and prognoses of patients with NTM-PD diagnosed from both specimen types.

Methods

We analysed data from patients who participated in the Seoul National University Hospital NTM-PD cohort (ClinicalTrials.gov identifier: NCT01616745). Baseline demographics, symptoms, radiographic findings, disease progression, and treatment responses were summarized and compared between patients diagnosed from sputum specimens and patients diagnosed from bronchoscopic specimens.

Results

Three hundred forty-seven patients were included in the analyses. Of these, 279 (80.4%) were diagnosed from two separately expectorated sputum specimens, and 68 (19.6%) were diagnosed from bronchoscopic specimens. Patients diagnosed from sputum specimens had more frequent and severe cough, sputum, postnasal drip, and high St. George’s Respiratory Questionnaire scores. However, the extent and severity of the radiographic lesions, disease progression, and treatment responses were similar for both groups. Further analysis based on the following three groups (sputum culture positive, sputum culture negative/bronchoscopy, and scanty sputum/bronchoscopy groups) suggested that the scanty sputum/bronchoscopy group appeared to have the worst prognosis in terms of both time to progression and time to culture conversion.

Conclusions

Although some symptoms and quality of life were worse in patients with NTM-PD diagnosed from sputum specimens, their prognoses were similar to those of patients diagnosed by bronchoscopic specimen. We recommend bronchoscopic sampling for patients in whom NTM-PD is suspected clinically or radiographically, especially those who have no or scanty sputum.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-4078-0) contains supplementary material, which is available to authorized users.

Characteristics of patients with bronchoscopy-diagnosed pulmonary Mycobacterium avium complex infection

BACKGROUND

We occasionally treat patients with clinically suspected pulmonary Mycobacterium avium complex (MAC) infection and negative MAC culture on bronchoscopy.

OBJECTIVE

This study aimed to investigate the usefulness of bronchoscopy in patients with suspected MAC lung disease with nodular bronchiectasis on chest computed tomography (CT) and to clarify the clinical characteristics of these patients.

METHODS

We reviewed the records of 71 patients with clinically suspected pulmonary MAC infection on chest CT who underwent bronchoscopy. The patients were classified on the basis of MAC culture result, and their clinical characteristics were compared.

RESULTS

MAC was detected in 33 of the 71 (46.5%) patients (positive group), and 35 (49.3%) were culture-negative for nontuberculous mycobacteria (NTM) (negative group). NTM other than MAC were detected in 3 of 71 (4.2%) patients. MAC was not detected in 14 of 38 (36.8%) patients positive for GPL core IgA antibody. Patients in the positive group had a higher body mass index (20.1 ± 3.4 vs 18.5 ± 2.9 kg/m²; p = 0.047) and positive rate for GPL core IgA antibody (72.7% vs 40%; p = 0.006) and a lower chronic obstructive pulmonary disease assessment test score (6.6 ± 6.6 vs 11.7 ± 8.5; p = 0.016) and rate of positive culture for Pseudomonas aeruginosa or Haemophilus influenzae (12.1% vs 45.7%; p = 0.003), as compared with the negative group.

CONCLUSION

Bronchoscopy is useful for diagnosis of MAC in patients who cannot be diagnosed by sputum examination. In addition, patients with pulmonary MAC disease had less severe subjective symptoms and weight loss than did those with a negative MAC culture on bronchoscopy.

Endobronchial Non-Tuberculosis Mycobacterium Infection Presenting in a Healthy Child

OBJECTIVES

To describe a safe and effective treatment for endobronchial Mycobacterium avium complex.

METHODS

Case report and literature review.

RESULTS

We present a case of endobronchial M. avium complex in a healthy child treated with serial carbon-dioxide laser excisions and antibiotic triple therapy using azithromycin, rifampin, and ethambutol. No current guideline for the treatment of these lesions in the pediatric population exists.

CONCLUSIONS

In patients with airway impingement, serial endoscopic surgical resection combined with antibiotics can provide safe and effective management.

Mycobacterium avium Complex Disease

Despite the ubiqitous nature of Mycobacterium avium complex (MAC) organisms in the environment, relatively few of those who are infected develop disease. Thus, some degree of susceptibility due to either underlying lung disease or immunosuppression is required. The frequency of pulmonary MAC disease is increasing in many areas, and the exact reasons are unknown. Isolation of MAC from a respiratory specimen does not necessarily mean that treatment is required, as the decision to treatment requires the synthesis of clinical, radiographic, and microbiologic information as well as a weighing of the risks and benefits for the individual patient. Successful treatment requires a multipronged approach that includes antibiotics, aggressive pulmonary hygiene, and sometimes resection of the diseased lung. A combination of azithromycin, rifampin, and ethambutol administered three times weekly is recommend for nodular bronchiectatic disease, whereas the same regimen may be used for cavitary disease but administered daily and often with inclusion of a parenteral aminoglycoside. Disseminated MAC (DMAC) is almost exclusively seen in patients with late-stage AIDS and can be treated with a macrolide in combination with ethambutol, with or without rifabutin: the most important intervention in this setting is to gain HIV control with the use of potent antiretroviral therapy. Treatment outcomes for many patients with MAC disease remain suboptimal, so new drugs and treatment regimens are greatly needed. Given the high rate of reinfection after cure, one of the greatest needs is a better understanding of where infection occurs and how this can be prevented.

The characteristics of patients with pulmonary Mycobacterium avium-intracellulare complex disease diagnosed by bronchial lavage culture compared to those diagnosed by sputum culture

BACKGROUND AND OBJECTIVE

The utility of bronchoscopy for the diagnosis of pulmonary Mycobacterium avium-intracellulare complex (MAC) disease has been reported; however, which patients require bronchoscopy remains unclear. Our objective was to identify the characteristics of the patients in whom bronchoscopy is needed for the diagnosis of MAC disease.

METHODS

Fifty-four patients with pulmonary MAC disease were divided into two groups according to established diagnostic criteria: 39 patients were diagnosed by sputum culture and 15 patients were diagnosed by bronchial lavage culture. We analysed the differences in demographic and clinical characteristics as well as microbiological and radiological data between the two groups.

RESULTS

There were no significant differences in age, sex, smoking status, MAC species, underlying diseases, or steroid use. Significantly more patients diagnosed by sputum culture than bronchial lavage culture had a positive sputum smear for acid-fast bacilli (79.5% vs. 0.0%, respectively; p < 0.001) and any symptoms (75.3% vs. 46.2%, respectively; p = 0.0059). No significant differences were found in the prevalence of each computed tomography finding, including nodules, air-space disease, bronchiectasis, and cavities. However, more patients diagnosed by sputum culture than bronchial lavage culture had abnormalities in the left upper division (48.7% vs. 13.3%, respectively; p = 0.017) and higher numbers of affected lobes (4.3 ± 1.4 vs. 3.3 ± 1.6, respectively; p = 0.034).

CONCLUSION

If patients suspected of having pulmonary MAC disease have a negative sputum smear, no symptoms, no abnormal findings in the left upper division, or fewer affected lobes on computed tomography, bronchoscopy might be needed for the diagnosis.

Relationship Between Lung Cancer and Mycobacterium Avium Complex Isolated Using Bronchoscopy

Introduction:

The incidence of Mycobacterium avium complex (MAC)-positive respiratory specimen cultures and MAC lung disease (MACLD) is increasing worldwide. This retrospective study aimed to assess the association between MAC culture-positive bronchoscopy specimens and lung cancer.

Materials and Methods:

The medical records of 1382 untreated lung cancer patients between 2003 and 2011 were collected using our hospital database. Of them, records for 1258 that had undergone bronchoscopy together with sampling for mycobacterial culture were reviewed. Patient characteristics were compared between those with MAC-positive/other nontuberculous mycobacteria (NTM)-negative bronchial washings and those with MAC-negative/other NTM-negative bronchial washings. Patients with MAC-positive lung cancer were cross-sectionally divided into MACLD and non-MACLD groups, and their features were assessed. Follow-up data for patients with lung cancer but without MACLD were reviewed for subsequent development of MACLD.

Results:

Of the 1258 patients with lung cancer, 25 (2.0%) had MAC-positive/other NTM-negative bronchial washings. The proportion of women (52% vs 30%; P = 0.0274) and patient age (72 years vs 69 years; P = 0.0380) were significantly higher in the MAC-positive/other NTM-negative lung cancer group (n = 25) than in the MAC-negative/other NTM-negative lung cancer group (n = 1223). There were 10 patients with lung cancer and MACLD and 15 without MACLD; significant differences in patient characteristics were not found between the two groups, and none of the 15 patients without MACLD subsequently developed MACLD.

Conclusion:

MAC culture-positive bronchial washing is positively associated with lung cancer. Female sex and advanced age, but not lung cancer characteristics, were found to be associated with MAC infection in patients with lung cancer.

US Cystic Fibrosis Foundation and European Cystic Fibrosis Society consensus recommendations for the management of non-tuberculous mycobacteria in individuals with cystic fibrosis

Non-tuberculous mycobacteria (NTM) are ubiquitous environmental organisms that can cause chronic pulmonary infection, particularly in individuals with pre-existing inflammatory lung disease such as cystic fibrosis (CF). Pulmonary disease caused by NTM has emerged as a major threat to the health of individuals with CF but remains difficult to diagnose and problematic to treat. In response to this challenge, the US Cystic Fibrosis Foundation (CFF) and the European Cystic Fibrosis Society (ECFS) convened an expert panel of specialists to develop consensus recommendations for the screening, investigation, diagnosis and management of NTM pulmonary disease in individuals with CF. Nineteen experts were invited to participate in the recommendation development process. Population, Intervention, Comparison, Outcome (PICO) methodology and systematic literature reviews were employed to inform draft recommendations. An anonymous voting process was used by the committee to reach consensus. All committee members were asked to rate each statement on a scale of: 0, completely disagree, to 9, completely agree; with 80% or more of scores between 7 and 9 being considered ‘good’ agreement. Additionally, the committee solicited feedback from the CF communities in the USA and Europe and considered the feedback in the development of the final recommendation statements. Three rounds of voting were conducted to achieve 80% consensus for each recommendation statement. Through this process, we have generated a series of pragmatic, evidence-based recommendations for the screening, investigation, diagnosis and treatment of NTM infection in individuals with CF as an initial step in optimising management for this challenging condition.

Limited value of transbronchial lung biopsy for diagnosing Mycobacterium avium complex lung disease

BACKGROUND AND AIMS

It remains unclear whether transbronchial lung biopsy (TBLB) is useful for diagnosing Mycobacterium avium complex (MAC) lung disease.

METHODS

Thirty-eight consecutive patients with MAC lung disease, who were evaluated with TBLB tissue culture between June 2006 and May 2010, were included. Bronchial washing (BW) and histopathological evaluation were performed in all patients. The positivity rates of BW and TBLB tissue culture, and typical histopathological findings for MAC disease were investigated. Furthermore, all patients were divided into two groups according to the presence of intrabronchial purulent or mucopurulent secretion and the clinical, bacteriological and pathological characteristics were compared between the two groups.

RESULTS

The positive culture rates of BW and TBLB specimens for MAC were 100% (38 patients) and 28.9% (11 patients). BW materials were much more sensitive for culture positivity than TBLB specimens (P < 0.0001). Typical pathological findings for MAC disease were present in the TBLB specimens of only 11 patients (28.9%). Intrabronchial secretion was identified in 15 patients (39.5%, secretion-positive group) and absent in 23 patients (60.5%, secretion-negative group). Typical histopathological findings for MAC disease were more common in the secretion-positive group than in the secretion-negative group (53.3% vs 13.0%, P = 0.01), although the radiological classification and smear positivity of BW were not different between the two groups.

CONCLUSION

TBLB for pathological and bacterial investigations would provide only a limited value for MAC diagnosis. Moreover, the presence of intrabronchial secretion may be an important manifestation of ongoing airway damage, which would require early treatment.

Role of bronchoalveolar lavage in the diagnosis of pulmonary infiltrates in immunocompromised patients

PURPOSE OF REVIEW

To describe the role of bronchoalveolar lavage (BAL) in the evaluation of pulmonary disease in immunocompromised patients.

RECENT FINDINGS

Recent discoveries in this field are largely in two areas: the array of diagnostic testing performed on BAL fluid and technical details that can enhance the yield from this procedure. Regarding diagnostic testing, the addition of new assays, including Aspergillus galactomannan antigen assay, respiratory viral panels, and Pneumocystis jirovecii PCR, has improved the diagnostic yield of BAL over conventional cultures and stains. To improve the diagnostic yield of the procedure itself, it should be done early in the clinical course, with the BAL in the anatomic area most affected, and with a preprocedural computed tomography of the chest to properly plan the procedure.

SUMMARY

Bronchoscopic evaluation with BAL can provide important diagnostic information in immunocompromised patients with pulmonary diseases and should be routinely performed when clinically indicated and able to be completed safely.

Characteristics of pulmonary Mycobacterium avium complex disease diagnosed later in follow-up after negative mycobacterial study including bronchoscopy

BACKGROUND

We occasionally experience cases suspected of pulmonary Mycobacterium avium complex (MAC) disease without positive bacterial cultures.

OBJECTIVE

To evaluate features of pulmonary MAC cases diagnosed later in the follow-up after negative intensive investigation.

METHODS

We defined and compared three groups; the first study negative (FSN) group, the first study positive (FSP) group, and MAC negative group. The FSN group consisted of patients negative for MAC isolation by bronchial washing performed between 2007 and 2011, but positive later. Patients with positive MAC cultures in the first study were incorporated into the FSP group. MAC negative group consisted of MAC suspects without MAC isolation in the follow-up.

RESULTS

Twenty-four patients were classified as FSN group, 61 as MAC negative group and 265 as FSP group. FSN group exhibited more solitary nodule pattern (n = 7 in FSN, n = 6 in FSP; p < 0.001) and less nodular/bronchiectatic (NB) diseases (n = 17 in FSN, n = 245 in FSP; p < 0.001). When limited to NB type, the FSP group had more cavitations (6% in FSN, 32% in FSP; p = 0.028). Patients with more than three lung lobes involved were more frequent in the FSN group compared with FSP group with negative sputum cultures (65% vs 34%; p = 0.014) and with MAC negative group (65% vs 28%; p = 0.009).

CONCLUSIONS

Patients diagnosed as pulmonary MAC disease in the follow-up duration tend to show solitary nodular pattern or NB pattern without cavitation. In FSN patients with NB pattern, more lung lobes were involved in the first study, suggesting subsequent MAC infection onto the underlying ectatic bronchi.

Lung transplantation for cystic fibrosis: results, indications, complications, and controversies

Survival in patients with cystic fibrosis (CF) has improved dramatically over the past 30 to 40 years, with mean survival now approximately 40 years. Nonetheless, progressive respiratory insufficiency remains the major cause of mortality in CF patients, and lung transplantation (LT) is eventually required. Timing of listing for LT is critical, because up to 25 to 41% of CF patients have died while awaiting LT. Globally, approximately 16.4% of lung transplants are performed in adults with CF. Survival rates for LT recipients with CF are superior to other indications, yet LT is associated with substantial morbidity and mortality (∼50% at 5-year survival rates). Myriad complications of LT include allograft failure (acute or chronic), opportunistic infections, and complications of chronic immunosuppressive medications (including malignancy). Determining which patients are candidates for LT is difficult, and survival benefit remains uncertain. In this review, we discuss when LT should be considered, criteria for identifying candidates, contraindications to LT, results post-LT, and specific complications that may be associated with LT. Infectious complications that may complicate CF (particularly Burkholderia cepacia spp., opportunistic fungi, and nontuberculous mycobacteria) are discussed.

Microbiological diagnosis of nontuberculous mycobacterial pulmonary disease

Pulmonary disease is by far the most frequent disease caused by nontuberculous mycobacteria (NTM). To diagnose NTM pulmonary disease (NTM-PD), patients should have symptoms and radiologic signs suggestive of NTM-PD, and cultures of multiple respiratory tract samples must grow the same NTM species. Thus, the microbiological laboratory has a central role in the diagnosis of NTM-PD. This review summarizes currently available data on techniques involved in the microbiological diagnosis of NTM-PD, and aims to provide a framework for optimal microbiological diagnosis.

Distribution of mycobacterial antigen based on differences of histological characteristics in pulmonary Mycobacterium avium infectious diseases--consideration of the extent of surgical resection from the pathological standpoint

Quantitative assessment of mycobacterial antigens is very important to determine the surgical indication, as well as the area of resection for pulmonary Mycobacterium avium complex (MAC) infectious disease. However, at present, pathological assessment is only possible as a postoperative examination. We performed quantitative evaluation of mycobacterial antigens using lung tissues with MAC pulmonary infection obtained from surgical resection. The distribution of mycobacterial antigens was evaluated by immunohistochemical staining with monoclonal antibody for mycobacteria. In exudative reactions, many monocyte-lineage cells containing mycobacterial antigens were observed in alveoli, whereas the quantity of mycobacterial antigens was extremely decreased in proliferative reactions. Epithelioid cells or multinucleated giant cells contained mycobacterial antigens in necrotic granulomas. In solitary nodules with central necrosis, mycobacterial antigens were frequently observed, whereas they were rarely observed in solitary nodules without caseous necrosis. Mycobacterial antigens were not observed in the epithelial layer of bronchioles in any cases, although proliferative granulomas were notably observed in the developed lymphoid follicles in subepithelial lesions of bronchiole. Thus, exudative reactions or nodules with caseous necrosis indicate the possibility of numerous mycobacteria remaining in the pulmonary focus. Therefore, intraoperative histological assessment may help in the determination of the area of surgical resection. This is the first study to quantitatively evaluate mycobacterial antigens according to histological characteristics in MAC pulmonary disease.

[Diagnosis and treatment of atypical mycobacterial infections of the respiratory tract]

INTRODUCTION

Non tuberculous mycobacteria (NTM), unlike tuberculous mycobacteria, are not strictly human pathogens. The diagnosis of infection and the choice of treatment remain difficult.

BACKGROUND

Evidence of a NTM in a pulmonary sample is not synonymous with infection. The diagnosis depends on the association of clinical, radiological and microbiological factors. If a NTM is isolated from a respiratory sample, the probability of infection depends on the species. The main NTMs responsible for pulmonary infection in France are Mycobacterium avium intracellulare, Mycobacterium xenopi, Mycobacterium kansasi and Mycobacterium abscessus. Their management is difficult and poorly understood. Treatment is well established for M. avium intracellulare and M. kansasii, with combinations of clarithromycin-rifampicin-ethambutol and isoniazid-rifampicin-ethambutol respectively. For M. xenopi, the optimal treatment is not known and a combination of clarithromycin-rifampicin-ethambutol, with moxifloxacin as an alternative, is currently recommended. In general, treatment is prolonged and often associated with problems of tolerance.

VIEWPOINT AND CONCLUSION

The management of NTM infection, taking into account of the increase in patients "at risk", is an important issue. Further studies are needed to improve the criteria for infection and to find the optimal therapeutic combinations.

Nontuberculous mycobacterial infections

CONTEXT

Nontuberculous mycobacteria include numerous acid-fast bacilli species, many of which have only recently been recognized as pathogenic. The diagnosis of mycobacterial disease is based on a combination of clinical features, microbiologic data, radiographic findings, and histopathologic studies.

OBJECTIVE

To provide an overview of the clinical and pathologic aspects of nontuberculous mycobacteria infection, including diagnostic laboratory methods, classification, epidemiology, clinical presentation, and treatment.

DATA SOURCES

Review of the pertinent literature and published methodologies.

CONCLUSIONS

Nontuberculous mycobacteria include numerous acid-fast bacilli species, many of which are potentially pathogenic, and are classified according to the Runyon system based on growth rates and pigment production. Their slow growth hinders cultures, which require special medium and prolonged incubation. Although such methods are still used, newer nucleic acid-based technologies (polymerase chain reaction and hybridization assays) can rapidly detect and speciate some mycobacteria--most notably, distinguishing Mycobacterium tuberculosis from other species. Infections caused by these organisms can present as a variety of clinical syndromes, not only in immunocompromised patients but also in immunocompetent hosts. Most common among these are chronic pulmonary infections, superficial lymphadenitis, soft tissue and osteoarticular infections, and disseminated disease. Treatment of nontuberculous mycobacterial infections is difficult, requiring extended courses of multidrug therapy with or without adjunctive surgical intervention.

[Clinical study on lung disease caused by non-tuberculous mycobacteriosis in the elderly]

AIM

This study was done to clarify the characteristics of elderly patients with nontuberculous mycobacteriosis.

METHODS

We investigated the clinical features of 10 patients at an advanced age who had been given diagnosis of nontuberculous mycobacteriosis.

RESULTS

Mycobacterium avium intracellulare complex (MAC) were detected in all cases. The age of the patients ranged from 65 to 92. Four cases had underlying respiratory diseases (old pulmonary tuberculosis in 3 cases, pulmonary emphysema in 1 case, bronchiectasia in 1 case). Six cases suffered from dementia. The symptoms were relatively nonspecific, such as low grade fever, fatigue, appetite loss in almost all cases in this study. On computed tomography (CT) scans of the chest, mainly small nodular infiltrates were seen. MAC was detected in clinical samples such as sputum, gastric juice and bronchial lavage. The examination of gastric juice was performed in 6 out of the 10 cases. Gastric juice samples were smear-positive for acid-fast bacilli in 5 of 6, and culture-positive for MAC in 5 of 6. The detection of MAC in gastric juice samples was higher than that in sputum samples on admission.

CONCLUSION

Gastric juice might be useful to differentiate infection from casual isolation of MAC in elderly patients.