Beyond Symptoms: Radiologic identification of asymptomatic Mycobacterium avium complex pulmonary infections

BACKGROUND

Although international nontuberculous mycobacterial pulmonary disease (NTM-PD) guidelines highlight symptom presence at diagnosis, the clinical characteristics of asymptomatic Mycobacterium avium complex pulmonary infection (MAC-PI) patients remain understudied. We clarified the clinical characteristics and course of asymptomatic MAC-PI patients.

METHODS

We retrospectively analyzed 200 consecutive patients with MAC-PIs and adequate available data who newly met the microbiological and radiological criteria for NTM-PD at Fukujuji Hospital from January 2018 to June 2020. We compared the clinical characteristics and course of asymptomatic patients with symptomatic patients and evaluated factors influencing treatment initiation through multivariate analysis.

RESULTS

111 patients were symptomatic and 89 were asymptomatic at diagnosis. While the proportion was significantly lower than that in the symptomatic group (28.8 %), 15.7 % of asymptomatic group patients had cavitary lesions (P = 0.042). In the asymptomatic group, treatments were initiated in 38 (42.7 %) patients, and cavitary lesions, a positive acid-fast bacilli smear, and younger age were independent risk factors for treatment initiation. Among 22 (57.9 %) patients who experienced disease progression necessitating treatment during follow-up, 13 (34.2 %) displayed radiological progression without any worsening of symptoms. Agents used for treatment were consistent across the groups, with no significant differences in culture conversion, microbiological recurrence rates, or spontaneous culture conversion rates.

CONCLUSION

Routine health checkups and radiological examinations can detect clinically important MAC-PIs even in the absence of symptoms. Considering that the clinical course of asymptomatic MAC-PI patients is largely similar to that of symptomatic patients, timely and appropriate management and intervention are essential for all MAC-PI patients.

Post-treatment Radiographic Severity and Mortality in Mycobacterium avium Complex Pulmonary Disease

Rationale: Imaging studies are widely performed when treating Mycobacterium avium complex pulmonary disease (MAC-PD); however, the clinical significance of post-treatment radiographic change is unknown. Objectives: To determine whether a deep neural network trained with pulmonary tuberculosis could adequately score the radiographic severity of MAC-PD and then to examine relationships between post-treatment radiographic severity and its change from baseline and long-term prognosis. Methods: We retrospectively collected chest radiographs of adult patients with MAC-PD treated for ⩾6 months at baseline and at 3, 6, 9, and 12 months of treatment. We correlated the radiographic severity score generated by a deep neural network with visual and clinical severity as determined by radiologists and mycobacterial culture status, respectively. The associations between the score, improvement from baseline, and mortality were analyzed using Cox proportional hazards regression. Results: In total, 342 and 120 patients were included in the derivation and validation cohorts, respectively. The network's severity score correlated with radiologists' grading (Spearman coefficient, 0.40) and mycobacterial culture results (odds ratio, 1.02; 95% confidence interval [CI], 1.0-1.05). A significant decreasing trend in the severity score was observed over time (P < 0.001). A higher score at 12 months of treatment was independently associated with higher mortality (adjusted hazard ratio, 1.07; 95% CI, 1.03-1.10). Improvements in radiographic scores from baseline were associated with reduced mortality, regardless of culture conversion (adjusted hazard ratio, 0.42; 95% CI, 0.22-0.80). These findings were replicated in the validation cohort. Conclusions: Post-treatment radiographic severity and improvement from baseline in patients with MAC-PD were associated with long-term survival.

Myosteatosis as a prognostic factor of Mycobacterium avium complex pulmonary disease

Quantitative body composition affects the prognosis of patients with Mycobacterium avium complex pulmonary disease (MAC-PD). However, whether the qualitative body composition obtained indirectly through computed tomography (CT) affects their prognosis is debatable. We retrospectively analyzed patients with MAC-PD who underwent non-contrast CT at MAC-PD diagnosis. The cross-sectional area of the erector spinae muscle (ESM area), the Hounsfield unit of the erector spinae muscle (ESM HU), and the cross-sectional area of subcutaneous fat (SQF area) were measured at the level of the first lumbar vertebra. Myosteatosis were defined below the median value of ESM HU for each sex. Of 377 patients, 45 (11.9%) died during the follow-up. Patients who died were older and had a lower ratio of females (33.3%). In body compositions, SQF area and ESM HU were lower in the patients who died. In multivariable analysis, a low ESM HU was associated with increased mortality (ESM HU adjusted hazard ratio [aHR] 0.95, 95% confidence interval [CI] 0.93-0.97) through body composition. SQF area revealed protective effects in MAC-PD patients with body mass index ≥ 18.5 kg/m2 (aHR 0.98, 95% CI 0.95-1.00). In conclusion, the decrease in ESM HU, which indirectly reflects myosteatosis, is associated with mortality in patients with MAC-PD.

A marmoset model for Mycobacterium avium complex pulmonary disease

RATIONALE

Mycobacterium avium complex, is the most common nontuberculous mycobacterial respiratory pathogen in humans. Disease mechanisms are poorly understood due to the absence of a reliable animal model for M. avium complex pulmonary disease.

OBJECTIVES

The objectives of this study were to assess the susceptibility, immunologic and histopathologic responses of the common marmoset (Callithrix jacchus) to M. avium complex pulmonary infection.

METHODS

7 adult female marmosets underwent endobronchial inoculation with 108 colony-forming units of M. intracellulare and were monitored for 30 or 60 days. Chest radiograph was assessed at baseline (prior to infection) and at the time of sacrifice (30 days for 3 animals and 60 days for 4 animals), and bronchoalveolar lavage cytokines, histopathology and cultures of the bronchoalveolar lavage, lungs, liver and kidney were assessed at time of sacrifice. Serum cytokines were monitored at baseline and weekly for 30 days for all animals and at 60 days for those alive. Group differences in serum cytokine measurements between those that tested positive versus negative for the M. intracellulare infection were assessed using a series of linear mixed models.

MEASUREMENTS AND MAIN RESULTS

Five of seven animals (two at 30 days and three at 60 days of infection) had positive lung cultures for M. intracellulare. Extra-pulmonary cultures were positive in three animals. All animals appeared healthy throughout the study. All five animals with positive lung cultures had radiographic changes consistent with pneumonitis. At 30 days, those with M. intracellulare lung infection showed granulomatous inflammation, while at 60 days there were fewer inflammatory changes but bronchiectasis was noted. The cytokine response in the bronchoalveolar lavage fluid was uniformly greater in the animals with positive M. intracellulare cultures than those without a productive infection, with greater levels at 30-days compared to 60-days. Similarly, serum cytokines were more elevated in the animals that had positive M. intracellulare cultures compared to those without a productive infection, peaking 14-21 days after inoculation.

CONCLUSION

Endobronchial instillation of M. intracellulare resulted in pulmonary mycobacterial infection in marmosets with a differential immune response, radiographic and histopathologic abnormalities, and an indolent course consistent with M. avium complex lung infection in humans.

Radiologic Subtypes and Treatment Outcome of Unclassifiable Type Mycobacterium avium Complex Pulmonary Disease

BACKGROUND

Although the "unclassifiable type" is categorized as one of the radiologic classifications in Mycobacterium avium complex (MAC) pulmonary disease (PD), there have been few studies of this type thus far. We aimed to investigate the radiologic subtypes and treatment outcome of unclassifiable type MAC-PD.

METHODS

Ninety-six patients with unclassifiable type MAC-PD who initiated a macrolide-containing regimen from 2001 to 2020 were identified at a tertiary referral center in South Korea. Among these 96 patients, 1-year culture conversion rate was analyzed for 48 patients who received standard treatment (three-drug oral-antibiotic combination with or without an injectable agent) for ≥ 1 year.

RESULTS

The mean age of the 96 patients was 65.4 ± 10.8 years, and 72.9% of them were male. These patients were classified into four major radiologic subtypes; the most common subtype was the focal cavity subtype (n = 31, 32.3%), followed by the focal mass or nodule (n = 23, 24.0%), consolidation upon emphysema (n = 21, 21.9%), and bronchiolitis (n = 21, 21.9%) subtypes. For the 48 patients who received standard treatment for ≥ 1 year, the overall rate of culture conversion at 1-year was 93.8%. All patients in the focal cavity subtype and focal mass or nodule subtype categories achieved 1-year culture conversion. Additionally, 1-year culture conversion rate was 92.9% in consolidation upon emphysema subtype and 75.0% in bronchiolitis subtype.

CONCLUSION

Unclassifiable type MAC-PD can be radiologically further categorized into four major radiologic subtypes. The treatment outcome of all of these subtypes seems to be favorable.

Neutrophil-Lymphocyte Ratio and Monocyte-Lymphocyte Ratio According to the Radiologic Severity of Mycobacterium avium Complex Pulmonary Disease

BACKGROUND

To date, no study has investigated whether the neutrophil-lymphocyte ratio (NLR) and monocyte-lymphocyte ratio (MLR) have a clinical value in Mycobacterium avium complex (MAC)-pulmonary disease (PD).

METHODS

We aimed to assess whether the baseline NLR and MLR were different according to the severity of MAC-PD based on the radiologic classification by retrospectively analyzing 549 patients treated in a tertiary referral center in South Korea.

RESULTS

Both NLR and MLR were significantly higher as 3.33 and 0.43 respectively in the fibrocavitary type, followed by 2.34 and 0.27 in the cavitary nodular bronchiectatic type and significantly lower as 1.88 and 0.23 in the non-cavitary nodular bronchiectatic type.

CONCLUSION

The baseline NLR and MLR showed a distinct difference in accordance with the radiologic severity of MAC-PD.

Predictors of radiological aggravations of pulmonary MAC disease

Background and objectives

The number of patients with pulmonary Mycobacterium avium complex (MAC) disease is increasing worldwide, especially among middle-aged women and never-smokers.

However, little is known about the factors causing exacerbations of pulmonary MAC disease in untreated patients. The aim of the present study was to identify the predictors of radiological aggravations of pulmonary MAC disease.

Methods

From April 2011 to December 2018, 238 MAC patients at our institute were newly diagnosed with pulmonary MAC disease according to the 2007 American Thoracic Society/Infectious Disease Society guideline. Their medical records were examined retrospectively for their clinical findings. The radiological findings at the time of the diagnosis and 1 year later were evaluated. To identify the predictors of radiological aggravation, multivariable analysis was performed with the data of 167 treatment-naïve patients.

Results

Female, never-smoker, and nodular/bronchiectatic (NB) type were predominant in patients with pulmonary MAC disease. Univariate analysis of data from treatment-naïve subjects showed that no lung diseases other than MAC, extensive radiological findings, and a positive acid-fast bacilli (AFB) smear were significantly associated with radiological aggravations. On multivariate analysis, the radiological factor (larger affected area) and absence of other lung disease were significantly associated with radiological aggravations. In particular, the presence of abnormal shadows in more than 3 lobes was significantly associated with radiological aggravations.

Conclusions

In this study, the presence of extensive radiological findings and the absence of lung diseases other than MAC were predictors of radiological aggravations of treatment-naïve pulmonary MAC disease. In particular, the presence of abnormal shadows in more than 3 lobes was significantly associated with radiological aggravations.

Insufficient serum L-ficolin is associated with disease presence and extent of pulmonary Mycobacterium avium complex disease

BACKGROUND

The incidence of infectious disease caused by nontuberculous mycobacteria is increasing worldwide. Pulmonary Mycobacterium avium complex (MAC) disease is difficult to treat with chemotherapy, and its mechanism of infection, infection route, disease onset, and severity remain unknown. Ficolins are oligomeric defense lectins. L-ficolin plays an important role in innate immunity. This study's aim was to identify L-ficolin's role in patients with pulmonary MAC disease.

METHODS

Between April 2011 and September 2017, 61 Japanese patients with pulmonary MAC disease were seen at our hospital. A control group, comprising 30 healthy individuals, without respiratory disease were enrolled in our study. The relationship between serum L-ficolin levels and disease severity was assessed, and L-ficolin's antibacterial role was examined.

RESULTS

Serum L-ficolin levels were significantly lower in patients with pulmonary MAC disease than in healthy subjects (1.69 ± 1.27 μg/ml vs. 3.96 ± 1.42 μg/ml; p < 0.001). The cut-off value, based on receiver operating characteristic (ROC) analysis results, was 2.48 μg/ml (area under the curve (AUC) 0.90, sensitivity and specificity 83.6 and 86.7%, respectively). Serum L-ficolin levels were significantly lower in the patients with nodular bronchiectatic type disease compared with the patients with fibrocavitary type disease and were lower in the high-resolution computed tomography high-scoring group compared with low-scoring group. An in vitro analysis showed that purified recombinant L-ficolin bound to M. avium and its major cell wall component, lipoarabinomannan, in a concentration-dependent manner. In addition, recombinant L-ficolin suppressed M. avium growth in a concentration-dependent manner.

CONCLUSIONS

Insufficient serum L-ficolin is associated with disease progression in pulmonary MAC disease, and the level of serum L-ficolin is a possible biomarker.

TRIAL REGISTRATION

This study is registered with UMIN ( UMIN000022392 ).

Retrospective evaluation of natural course in mild cases of Mycobacterium avium complex pulmonary disease

Background

There is no proven management for mild cases of Mycobacterium avium complex (MAC) pulmonary disease, who do not immediately receive treatment and are managed with observation alone, because its long term-natural course, factors predictive of deterioration, and the effect of treating the disease remain unclear. Thus, we sought to investigate the natural course of mild cases of MAC pulmonary disease.

Methods

We conducted a multicenter retrospective study. Sixty-five patients with mild MAC pulmonary disease in whom treatment was withheld for at least 6 months after diagnosis were retrospectively recruited after a review of 747 medical records. Longitudinal changes in clinical features were evaluated by using a mixed effects model.

Results

Mean follow-up was 6.9 ± 5.7 years. During the follow-up period, 15 patients (23%) required treatment and 50 (77%) were managed with observation alone. At diagnosis, 65 patients had nodular bronchiectatic disease without fibrocavitary lesions. Among clinical features, mean body mass index (BMI), forced expiratory volume in 1 second as percent of forced vital capacity (%FEV₁), nodular lung lesions, and bronchiectasis worsened significantly in the observation group during follow-up. In the treatment group, BMI, and %FEV₁ were stable, but bronchiectasis significantly worsened. At diagnosis, the polyclonal MAC infection rate in the treatment group was higher than that in the observation group. Other microbiological factors, such as insertion sequences, did not differ significantly between the groups.

Conclusions

Mild MAC pulmonary disease progresses slowly but substantially without treatment. Treatment prevents the deterioration of the disease but not the progression of bronchiectasis. Polyclonal MAC infection is a predictor of disease progression.

[Pulmonary Non-tuberculous Mycobacteriosis Complicated with Pulmonary Large Cell Neuroendocrine Carcinoma;Report of a Case]

A 64-year-old man with pulmonary non-tuberculous mycobacteriosis(pulmonary NTM) who had been treated by antituberculous chemotherapy, developed a new nodule of 8 mm in size in the segment 3 of the right upper lobe. The cavity of 4.0 cm in size in the segment 1+2 of the left upper lobe due to Mycobacterium avium infection was preexisted. Radiologically, new nodule of the right lung was suspected to be lung cancer. Left upper lobe apical trisegmentectomy was performed at first. Three months later, enlarging of the right lung nodule with increased fluoro-2-deoxy-D-glucose(FDG) activity was noted, and the diagnosis of lung cancer was made by transbronchial lung biopsy(TBLB). Then, right upper lobectomy with systematic nodal dissection were performed.

Neutrophil predominance in bronchoalveolar lavage fluid is associated with disease severity and progression of HRCT findings in pulmonary Mycobacterium avium infection

Pulmonary Mycobacterium avium complex (MAC) infection is increasing in prevalence worldwide even in immunocompetent individuals. Despite its variable clinical course, the clinical and immunological factors associated with radiographical severity and progression are not largely unknown. We aimed to study the association between the inflammatory cell and cytokine profiles at the local infected site, and the radiological severity and/or progression of pulmonary MAC infection. In this retrospective cohort study, 22 healthy subjects and 37 consecutive patients who were diagnosed as having pulmonary MAC infection by positive cultures of bronchoalveolar lavage (BAL) fluids were enrolled. The 37 patients were divided into 2 groups based on the predominant BAL inflammatory cell type: the lymphocyte-dominant (LD) group and neutrophil-dominant (ND) groups. The high-resolution computed tomography score in both the lavaged segment and whole lung and cytokines profiles were compared between the 2 groups. The clinical course after the BAL procedure was also compared between the 2 groups. Both the segment and whole lung scores in the ND group were significantly higher than the LD group (P < 0.001). Levels of IL-8 in the BAL fluids were significantly higher in the ND group compared to the LD group (P = 0.01). In contrast, levels of IL-22 were significantly lower in the ND group compared to the LD group (P < 0.001). The prevalence of patients who showed deterioration of the disease was significantly higher in the ND group (83.3%) than the LD group (12.5%) (P < 0.01).

Neutrophil-predominant inflammatory response at the infected site is associated with the radiographical severity and progression of pulmonary MAC infection.

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.

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.

Epidemiology and clinical features of pulmonary nontuberculous mycobacteriosis in Nagasaki, Japan

BACKGROUND AND OBJECTIVES

Recent reports indicate that the incidence of nontuberculous mycobacterial-lung disease (NTM-LD) is increasing. This study aimed to investigate the epidemiology and clinical features of NTM-LD patients in Nagasaki prefecture, Japan to identify the negative prognostic factors for NTM-LD in Japan.

METHODS

The medical records of patients newly diagnosed with NTM-LD in eleven hospitals in Nagasaki prefecture between January 2001 and February 2010 were reviewed. Data regarding the annual population of each region and the incidence of all forms of tuberculosis were collected to assess geographic variations in NTM-LD incidence, isolates, and radiological features.

RESULTS

A total 975 patients were diagnosed with NTM-LD. The incidence increased over the study period and reached 11.0 and 10.1 per 100,000 population in 2008 and 2009, respectively. M. intracellulare was the most common pathogen in the southern region, and M. avium most common in other regions. The most common radiographic pattern was the nodular-bronchiectatic pattern. Age >60 years, body mass index <18.5 kg/m2, underlying lung disease, and cavitary pattern were the negative prognostic factors at the 1-year follow-up.

CONCLUSIONS

The incidence of NTM-LD has been increasing in Nagasaki prefecture. The isolates and radiographic features of patients vary markedly by region.

[A HEALTHY ADULT WITH DISSEMINATED NONTUBERCULOUS MYCOBACTERIAL INFECTION WITH MULTIPLE BONE LESIONS]

A 54-year-old man was admitted to our hospital because of fever, dyspnea, and low back pain. Chest computed tomography showed a 30-mm mass in the left lung and bilateral pleural fluids, multiple bone lesions, enlarged lymph nodes, and skin abscesses. Mycobacterium avium was isolated from his sputum, a pleural fluid sample, the right cervical lymph node, and a precordial skin abscess. We thus diagnosed his illness as disseminated nontuberculous mycobacterial infection (DNTM) and treated him with multiple chemotherapeutic agents. However, the disease progressed, and he ultimately died. He was not in an obvious immunocompromised state. DNTM with multiple bone lesions in a healthy adult is very rare and we therefore report this case.

[Pulmonary non-tuberculous mycobacteriosis complicated with lung cancer]

A 54-year-old man with pulmonary non-tuberculous mycobacteriosis( pulmonary NTM) who had been treated by antituberculous chemotherapy, developed a new nodule of 1.3 cm in size in the segment 1/2 of the right upper lobe. The cavity of 3.5 cm in size in the segment 6 of the right lower lobe from which Mycobacterium intracellulare was bronchoscopically detected, was suspected to be pulmonary NTM lesion. Since lung cancer was highly suspected by radiological examinations, right upper lobectomy and S6 segmentectomy were performed. Pathological diagnosis for the right upper lobe nodule was adenocarcinoma.

Serum glycopeptidolipid core IgA antibody levels in patients with chest computed tomography features of mycobacterium aviumintracellulare complex pulmonary disease

Measurement of serum glycopeptidolipid core IgA antibody (GPL antibody) was recently reported to show a high sensitivity and specificity for diagnosing Mycobacterium avium-intracellulare complex (MAC) pulmonary disease (MAC-PD), but its clinical value has not been confirmed. This study aims to evaluate the seropositive rate in patients with suspected MAC-PD based on chest computed tomography (CT), and to examine whether GPL antibody reflects the extent of lung involvement on CT or the number of bacteria in sputum, retrospectively. Among 66 patients with suspected MAC-PD on CT, 36 patients were negative for MAC by culture and 30 were positive. Sputum grades of MAC were evaluated by fluorochrome microscopy of sputum smears. The lungs were divided into six regions to assess the extent of disease. Serum levels of GPL antibody were measured with an enzyme immunoassay (cut-off value >0.7 U/ml). The GPL antibody positive rate was 19.4% among patients who were negative for MAC by culture versus 73.3% among culture–positive patients. The serum level of GPL antibody was significantly correlated with the sputum smear grade (r=0.43, p less than 0.05) and was also correlated with the number of lung regions showing MAC-PD features on CT (r=0.43, less than 0.05). Some MAC-PD patients may have CT features of MAC with positive level of GPL antibody, although the diagnosis cannot be confirmed by culture. GPL antibody levels reflect the pulmonary burden of MAC, as assessed from the sputum smear grade and number of involved regions on chest CT.

Nutritional indicators are correlated with the radiological severity score in patients with Mycobacterium avium complex pulmonary disease: a cross-sectional study

OBJECTIVE

Body weight loss in patients with Mycobacterium avium complex (MAC) pulmonary disease can be fatal. The administration of nutritional supplements should be an important component in the treatment of this disease. Objective data regarding the association between the nutritional status and disease severity have not been reported. This cross-sectional study aimed to compare the nutritional status and radiological severity scores in MAC pulmonary disease patients.

METHODS

We retrospectively reviewed the records of 40 patients who were admitted to our institution for the treatment of MAC pulmonary disease between July 2008 and July 2010. Nutritional indices, including the ideal body weight ratio, triceps skinfold, mid-upper arm muscle circumference, and percentage of predicted resting energy expenditure, were compared with the radiological severity scores. Quantitative values of the extent of nodules, infiltration shadows, cavities, and bronchiectasis on the computed tomography scans were used to evaluate the radiological severity scores.

RESULTS

The patients suffered from a significantly decreased percentage of ideal body weight, body fat and muscle mass. The average radiological score was 17.6±8.4 points. The percentage of ideal body weight (p<0.001), percentage of triceps skinfold (p<0.001) and percentage of mid-upper arm muscle circumference (p<0.002) were negatively correlated with the radiological scores, while the percentage of the predicted resting energy expenditure (p<0.001) was positively correlated with the scores.

CONCLUSION

A poor nutritional status is common in patients with progressive MAC pulmonary disease, which supports the hypothesis that aggressive nutritional interventions are indicated in the treatment of this disease.

[Distribution of pulmonary Mycobacterium avium complex (MAC) disease cavities and their course under chemotherapy]

The presence of a cavitary lesion is important factor for pulmonary Mycobacterium avium complex (MAC) treatment.

PURPOSE

Clarify the location of pulmonary MAC cavities and the changes of these cavities.

MATERIAL & METHODS

We observed the location of 56 cavities in 48 patients with pulmonary MAC on computed tomography (CT) images and evaluated the changes in the external diameter of these cavities before and after treatment with a regimen of rifampicin (RFP), ethambutol (EB), and clarithromycin (CAM).

RESULTS

These pulmonary MAC cavities were significantly frequently located in segments S2, S3, S9, and S10, and their distribution was different from that of pulmonary tuberculosis at the patients' initial visit. Examination of the external diameters of these cavities after chemotherapy showed that 42.1% of cavities expanded, 0.2% were unchanged, and 56.1% shrank. The mean diameter of the cavities decreased significantly (by 3.1 mm) after chemotherapy. The mean size of the cavities in the upper lobe did not differ from the mean size of the cavities in the lower lobe before chemotherapy; however, the reduction in cavity size was significantly higher in the lower lobe cavities. In 14 cases, the cavities disappeared under the standard chemotherapy regimen in an average of 971 days, and there was a tendency for lower lobe cavities to disappear more rapidly.

[Lady Windermere syndrome]

We describe the case of a 68 year old lady with a pectus excavatum, chronic cough, dyspnoea, and fever. The CT scan showed fibronodular infiltrates and bronchectases. Bacterial culture revealed a Mycobacterium avium-intracellulare infection. A tritherapy was initiated and, 10 months later, the patient had greatly improved.

Bronchoscopic microsampling for bacterial colony counting in relevant lesions in patients with pulmonary Mycobacterium avium complex infection

OBJECTIVE

The incidence of pulmonary Mycobacterium avium complex (MAC) infections with nodular/bronchiectasis lesions is increasing. However, factors determining deterioration are unknown. In the present study, we investigated quantitative MAC cultures obtained through bronchoscopic microsampling (BMS) from patients with pulmonary MAC infection and analyzed the relationship between MAC culture and the short-term natural history. We also assessed chest computed tomography (CT) findings for the deteriorating factors.

DESIGN

For this prospective study, MAC was collected from peripheral lung lesions by BMS through endobronchial ultrasonography. MAC colonies were counted on Middlebrook 7H11 agar. We compared the number of MAC colonies with laboratory data and chest CT findings.

PATIENTS

We studied 26 patients with pulmonary MAC infection.

RESULTS

The patients were divided into 2 groups: 11 patients in the non-deteriorated group and 15 patients in the deteriorated group. The number of MAC colonies was significantly correlated with deterioration of MAC infection (p < 0.001). In the non-deteriorated group, chest CT scans showed nodular/bronchiectasis lesions in 8 patients (73%) and consolidated lesions in 3 patients (27%). In the deteriorated group, chest CT scans showed nodular/bronchiectasis lesions in 1 patient (7%), consolidated lesions in 6 patients (40%), and cavitary lesions in 8 patients (53%).

CONCLUSION

The number of MAC colonies in relevant lesions investigated by BMS was significantly larger in the deteriorated group than in the non-deteriorated group. Cavitary and consolidated lesions observed from chest CT scans are thought to indicate a high risk of progression of pulmonary MAC infection.

Consolidations in nodular bronchiectatic Mycobacterium avium complex lung disease: Mycobacterium avium complex or other infection?

PURPOSE

The objective of this study is to define the clinical implications of consolidations in nodular bronchiectatic type Mycobacterium avium complex (NBMAC) infection.

MATERIALS AND METHODS

A total of 69 patients (M : F = 17 : 52; mean age, 64 years; age range, 41-85 years) with MAC isolated in the sputum culture and nodular bronchiectasis on the initial and follow-up CT scans were included. We retrospectively reviewed the incidence of consolidation and analyzed its clinical course by using radiographic changes with or without anti-MAC drug therapy.

RESULTS

In 44 of the 69 cases (64%), focal consolidations were seen on the initial and follow-up CT images. In 35 of the 44 (80%) cases, consolidations completely regressed, and in 3 cases (7%), consolidations partially regressed within 2 months with only antibiotics. In 2 cases (5%), the consolidations remained stable for over 2 months without anti-MAC drug therapy. Only in 4 cases (9%) did the consolidations improve after anti-MAC drug therapy. In 11 of the 38 cases (29%) with responsiveness to antibiotics, non-mycobacterial micro-organisms were identified in sputum, including pseudomonas, hemophilus, staphylococcus, and others.

CONCLUSION

In NB-MAC, consolidations are commonly present on CT. In these conditions, most of consolidations result from pneumonia other than MAC.

[Pulmonary Mycobacterium avium-intracellulare complex disease that presented multiple nodular shadows rapidly]

The patient was 81-year-old woman diagnosed with lung cancer who underwent upper right lobectomy in January 2002. Computed tomography (CT) of the thorax showed a mass shadow presenting rapid-growing in the left S3 in August, 2008. The size of the mass shadow in the left S3 increased on day 16 after hospitalization, and a nodular shadow appeared in the left S(1+2). The bronchial washing specimen showed acid-fast bacilli identified as Mycobacterium intracellulare by deoxyribonucleic acid (DNA) -DNA hybridization (DDH). The patient showed radiological improvement following combination chemotherapy with rifampicin, ethambutol and clarithromycin.

[Chest X-ray image findings of Mycobacterium avium complex (MAC) lung disease]

Recently Mycobacterium avium complex (MAC) lung disease has increased in number remarkably in Japan. The MAC lung disease is divided into four types: a nodular bronchiectatic disease, a fibrocavitary disease, a hypersensitivity like disease, and a disseminated disease. Since the latter two types are rare, it is important in the diagnosis and treatment to understand the images of the former two. Formerly the fibrocavitary disease was more common, which occurred in the preceding tuberculous lesion frequently and showed images similar to tuberculosis. But recently the nodular bronchiectatic disease has increased in number particularly. Characteristic feature of this type is involving the right middle lobe and left lingual segment overwhelmingly in nonsmoking, immunocompetent, middle-aged women. Common CT manifestations of the nodular bronchiectatic disease include nodules just beneath the pleura, consolidation including bronchiectasis, and, lung volume shrinkage.

[A case of pulmonary Mycobacterium avium infection presenting multiple nodules with substantial difference in 18F-fluorodeoxyglucose uptake]

A 56-year-old man presented with a chief complaint of chronic cough due to bronchial asthma and pulmonary emphysema in 2001, without any abnormal findings on chest CT. His symptoms improved with high-dose inhaled corticosteroid. In February 2004, multiple nodules without bronchiectasis appeared in the chest CT. Pulmonary Mycobacterium avium infection was diagnosed by bronchial lavage and sputum culture. After multiple nodules appeared and disappeared repeatedly without medication, most nodules vanished after administration of antituberculous drugs. In Feburary 2007, a rapidly growing mass appeared in the right upper lobe, and a new nodule emerged in the left upper lobe the following month. On 18F-fluorodeoxyglucose positron emission tomography (18 FDG-PET), a substantial difference in 18FDG uptake was observed although both lesions were shown to be caused by Mycobacterium avium infection by needle biopsy. The lung specimen of the lesion with high 18FDG uptake demonstrated neutrophil infiltrates, suggesting acute inflammation. On the other hand, neutrophil infiltrates were not observed in the lesion with low uptake. We conclude that the degree of 18FDG uptake is not useful to decide when to initiate therapy and evaluate the efficacy of treatment.

Comparison of clinical and radiographic characteristics between nodular bronchiectatic form of nontuberculous mycobacterial lung disease and diffuse panbronchiolitis

The nodular bronchiectatic form of nontuberculous mycobacterial (NTM) lung disease and diffuse panbronchiolits (DPB) show similar clinical and radiographic findings. The present study was performed to clarify the clinicoradiographic similarities as well as the differences between NTM lung disease and DPB. The initial clinicoradiographic features of 78 patients with the nodular bronchiectatic form of NTM lung disease (41 patients with Mycobacterium avium complex infection and 37 patients with Mycobacterium abscessus infection) were compared with those of 35 patients with DPB. Old age, female sex, a history of tuberculosis treatment, and hemoptysis were related to NTM lung disease while exertional dyspnea, coarse crackles, history of sinusitis, obstructive abnormalities in pulmonary function tests, and hypoxemia were related to DPB. The number of lobes involved with bronchiolitis and bronchiectasis on chest computed tomography were more numerous in DPB patients. There is considerable overlap in the clinical and radiographic appearances of the nodular bronchiectatic form of NTM lung disease and DPB, although some clinicoradiographic features differ between two diseases. The correct diagnosis, including aggressive microbiologic evaluation, should be made for the appropriate management of patients presenting with bilateral bronchiectasis and bronchiolitis.

[Solitary pulmonary nodule due to Mycobacterium intracellulare showing intense uptake on 18F-fluorodeoxyglucose-positron emission tomography]

A 71-year-old woman with no respiratory symptoms, was admitted because of a solitary pulmonary nodule on a chest radiograph. Computed tomography revealed a 2.0 cm nodule with pleural indentation in the right S2. 18F-fluorodeoxyglucose-positron emission (18F-FDG-PET) showed positive tumor uptake (maximum standardized uptake value = 4.8). Bronchoscopy yielded no specific histological or bacterial findings. Lung biopsy using video-associated thoracoscopy revealed an epithelial granuloma with caseation, but no acid-fast bacilli were detected. PCR revealed Mycobacterium intracellulare (M. intracellulare). A solitary nodule caused by M. intracellulare is rare, but it should be considered in the differential diagnosis even with intense uptake on 18F-FDG-PET.

Mycobacterium avium complex pulmonary disease: management options in HIV-negative patients

OBJECTIVE

We present a case series and review of the literature of the management options in non-HIV-infected patients with Mycobacterium avium complex pulmonary disease (MAC-PD) with a focus on treatment failure and drug resistant disease.

CASE SERIES

Five case histories are presented, depicting various clinical scenarios necessitating different approaches to therapy and highlighting the limitations and complications of these options.

DISCUSSION

Mycobacterium avium complex (MAC) is well recognized as a significant cause of pulmonary disease in non-HIV infected patients and in those with intact immunity. Isolation of non-tuberculous mycobacteria (NTM) in culture is essential for the diagnosis of NTM lung disease. The typical presentation of MAC lung disease is apical fibrocavitary lung disease in men in their late 40s and early 50s who have a history of cigarette smoking and, frequently, excessive alcohol use. Other presentations of NTM lung disease include nodular bronchiectasis, solitary or multiple pulmonary nodules, and hypersensitivity pneumonitis. When indicated, the standard recommended treatment for most patients is a three-times-weekly regimen of clarithromycin or azithromycin, rifampin, and ethambutol with or without amikacin. Daily therapy is recommended for fibrocavitary disease. Based on published studies, macrolides are the only agents used for treatment of MAC disease for which there is a correlation between in vitro susceptibility and in vivo (clinical) response. Data regarding treatment of macrolide-resistant MAC (MRMAC) and multi-drug resistant MAC (MDRMAC) is sparse. Several drugs have been evaluated in drug-resistant MAC and have potential as effective therapy. Use of multiple drugs to which the isolate is susceptible is preferred to avoid development of future resistance. Surgery in mycobacterial disease is technically difficult, but selected patients with focal disease do benefit from resection of the involved lung.

CONCLUSIONS

MAC has protean pulmonary manifestations, especially in those with no recognizable impairments in their immune system. Drug treatment, however, remains difficult with high failure rates and poor long-term sputum conversion. This case series is based on our clinical experience highlighting treatment options and the often unrecognized morbidity and mortality of severe, progressive MAC-PD. It underscores the need for increased awareness of MAC-PD and MDRMAC and the difficulties encountered in their management.

A case of Mycobacterium avium complex infection in an immunocompetent man presenting with pericarditis and an HRCT pattern of lymphangitis

Non-tuberculous mycobacterial infections are rare in immunocompetent subjects. We describe the case of a 47-year-old previously healthy man with a Mycobacterium avium complex infection presenting with acute pericarditis and an atypical radiological pattern of lymphangitis.

Mycobacterium intracellulare pulmonary infection which co-existed and mimicked lung cancer

We report a case of Mycobacterium intracellulare (M. intracellulare) pulmonary infection with co-existing lung cancer and presenting as a solitary pulmonary nodule requiring differentiation from lung cancer. Computed tomography showed two nodules (20 mm) with spicula formation and pleural indentation on the right lower lobe of the lung (right S6 and S8). Transbronchial biopsies from the right S6 and S8 nodules revealed mycobacteriosis and adenocarcinoma, respectively. Thereafter, a right lower lobectomy was performed. Cases of pulmonary M. intracellulare disease with solitary nodule are rare. Moreover, M. intracellulare pulmonary infection with co-existing lung cancer is extremely rare.

[Nontuberculous mycobacterial infections involving solitary pulmonary nodules]

Over the course of 11 years (1993-2003) we encountered 5 cases of pulmonary nontuberculous mycobacterium (NTM) involving a solitary pulmonary nodule. In this report we analyze the chest computed tomography (CT) of these patients, the utility of bronchoscope and transthoracic fine-needle aspiration techniques, the mycobacterium species involved, and treatment results. Four of the 5 NTM cases were due to infection with M. avium and one was due to infection with M. intracellulare. The characteristic findings of the chest CTs were as follows: A solitary nodule was present just under the pleura. No definite distribution pattern was evident. Some cases had agglutinated nodules or fine calcifications. Although fiberoptic bronchoscopy was not used as a diagnostic tool in all 5 NTM cases and histological samples did not contain granulomas, we determined the presence of NTM and we also verified that no cancer cells were present in any of the 5 NTM patients, using transthoracic fine-needle aspiration. Four out of the 5 NTM patients were treated only with drug therapy and they displayed clinical improvement. We resected a solitary nodule in one of the 5 NTM patients because of slow response to drug therapy. We conclude that the solitary pulmonary nodule of NTM is often due to M. avium and that transthoracic fine-needle aspiration is an easy and effective method of detecting NTM.

[Mycobacterium avium complex infection which need to distinguish from lung cancer]

A 42 year old female was admitted to our hospital due to abnormal shadow on her chest X-ray. She had no symptoms. Chest X-ray and computed tomography (CT) scan revealed solitary nodule on left S10. Bronchofiberscopy was perfomed, but it could not establish pathological diagnosis. Thoracoscopic surgery was performed. It revealed that solitary nodule was Mycobacterium avium infection. Majority cases of Mycobacterium avium infection showed multiple nodules or infiltration shadows on bilateral lungs. But in our case, CT scan showed a solitary nodule, causing differential diagnosis from lung cancer to be difficult.

Solitary pulmonary granuloma caused by Mycobacterium avium-intracellulare complex

OBJECTIVES

To analyse the clinical features and high resolution computed tomography (HRCT) findings of solitary pulmonary granulomas caused by the Mycobacterium avium-intracellulare (MAI) complex.

METHODS

We retrospectively analysed a series of 73 consecutive patients with solitary pulmonary granuloma and negative sputum smear and culture results, in whom the diagnosis was established by histological examination of specimens obtained by partial pulmonary resection or lobectomy. We compared the clinical features and HRCT findings of the solitary pulmonary granulomas definitively diagnosed to be caused by the MAI complex with those of granulomas of other causes by univariate and multivariate analyses.

RESULTS

In this study series of 24 patients with solitary pulmonary granuloma, the aetiological agent was established as being the MAI complex. According to the results of the multivariate analysis, 'female sex', 'pleural indentation' and 'lobulation' on the HRCT images were significantly associated with solitary pulmonary granuloma caused by the MAI complex.

CONCLUSION

This study demonstrated several characteristics of solitary pulmonary granulomas caused by the MAI complex, and suggested that it might be a subtype of pulmonary MAI complex infection without the typical radiographic features of the infection.

Radiological findings of mycobacterial diseases

The diagnosis and treatment of mycobacterial diseases are very important clinical issues. Among mycobacterial diseases, pulmonary tuberculosis remains an important cause of morbidity and mortality throughout the world. Pulmonary tuberculosis demonstrates a variety of clinical and radiological features. In addition, the prevalence of Mycobacterium avium complex (MAC) has increased, especially in elderly women without underlying diseases. Clinically, there is a significant difference between tuberculosis and atypical mycobacterium infection in terms of the infection control measures adopted and the choice of treatment. Therefore, it is very important to know the characteristic radiological findings of mycobacterial diseases. In the present review, key radiological points for diagnosing mycobacterial diseases are discussed.

A double-blind randomized study of aminoglycoside infusion with combined therapy for pulmonary Mycobacterium avium complex disease

A prospective study of the clinical efficacy of an aminoglycoside antibiotic (streptomycin, SM) for the treatment of pulmonary Mycobacterium avium complex (MAC) disease was carried out. In a multicenter trial, patients with pulmonary MAC disease received protocol-guided combined chemotherapy with or without SM. SM was given to the patients intramuscularly 15 mg/kg three times per week for the initial 3 months and three other antibiotics (rifampicin, ethambutol, and clarithromycin) were added and administered for over 24 months after the conversion of MAC strains. From April 1998 to December 2004, 160 HIV-negative patients were enrolled in this trial. Fourteen patients were found to be ineligible because they could not continue the treatment, and they were excluded from the analysis after randomization. Seventy-three patients were assigned to receive combined chemotherapy with SM (group A) and 73 were assigned to receive combined chemotherapy without SM (group B). The median durations of treatment were 27.6 months in group A and 28.4 months in group B. The difference in the backgrounds of the groups was not statistically significant. There were no differences in microbiological and radiological findings between the groups, but the sputum conversion rate for pulmonary MAC disease at the completion of treatment was significantly higher in group A than that in group B. Although, there were no significant differences in the sputum relapse rate and clinical improvement including both clinical symptoms and radiological findings, group A showed better initial microbiological response than group B. As for adverse reactions and abnormal laboratory findings, there were no significant differences between the groups. Based on the results of this double-blind randomized study, we support treatment including SM according to both the American Thoracic Society (ATS) and the Japanese Society for Tuberculosis (JST) guidelines for patients with pulmonary MAC disease without HIV infection.

Pulmonary Mycobacterium intracellulare disease with a solitary pulmonary nodule detected at the onset of pneumothorax

A 61-year-old man with a past history of pulmonary emphysema 6 years earlier was admitted to the emergency department at our hospital because of cough and dyspnea. Left pneumothorax was recognized on a chest radiograph. After his admission to the emergency department, chest drainage was inserted and the left lung was expanded. Afterwards, a nodular shadow (>1.5 cm) was found in the left upper lobe, and differentiation from pulmonary adenocarcinoma was required. As a definite diagnosis could not be made by bronchoscopy, video-assisted thoracoscopic surgery was performed, and a solitary nodule in the left upper lobe was resected. Histologically, a caseating epitheloid granuloma with acid-fast bacilli was found. Regarding the causative pathogen, Mycobacterium intracellulare was identified from the surgically resected specimen. We have reported a peculiar case of pulmonary M. intracellulare disease, detected at the onset of left secondary pneumothorax caused by pulmonary emphysema, which required differentiation from pulmonary adenocarcinoma.

Increased serum level of vascular endothelial growth factor in Mycobacterium avium complex infection

OBJECTIVE

Pulmonary infection caused by Mycobacterium avium complex (MAC) is one of the granulomatous diseases which are associated with the expression of vascular endothelial growth factor (VEGF). The aim of the present study was to clarify the association of VEGF with the pathogenesis of MAC infection.

METHODOLOGY

The serum VEGF levels in 46 patients with pulmonary MAC infection were compared with those in 16 normal control subjects. Pulmonary lesions were evaluated using chest CT. In 20 patients, after treatment, serum VEGF levels were measured and chest CT performed again to evaluate pulmonary response to treatment.

RESULTS

Infected patients had higher serum VEGF levels than controls (435.2 +/- 29.1 vs. 167.0 +/- 10.6 pg/mL, P < 0.0001), and serum VEGF level correlated with the extent of disease. The serum VEGF levels in 14 patients who underwent treatment and exhibited an improvement in their pulmonary lesions decreased significantly compared with the results pretreatment (509.0 +/- 60.7 vs. 303.6 +/- 65.3 pg/mL, P = 0.0092). In infected patients, alveolar macrophages, epithelioid cells and multinucleated giant cells exhibited VEGF overexpression on immunohistochemical staining.

CONCLUSIONS

This study suggests that VEGF may be associated with the pathogenesis of pulmonary MAC infection. Additionally, serum VEGF levels may be a useful surrogate marker for evaluating the extent of disease and of the response to treatment.

Factors Related to Response to Intermittent Treatment ofMycobacterium aviumComplex Lung Disease

RATIONALE

Mycobacterium avium complex pulmonary disease (MAC-PD) is associated with substantial morbidity, and standard daily multidrug therapy is difficult to tolerate.

OBJECTIVES

To characterize response to a three-times-weekly (TIW) regimen of clarithromycin, ethambutol, and rifampin.

METHODS

A 1-yr prospective noncomparative trial of TIW treatment was conducted during 2000-2003 in 17 U.S. cities. Participants were 91 HIV-negative adults, diagnosed with moderate to severe MAC-PD, who originally participated in a trial of an inhaled IFN-gamma treatment. Improvement in sputum culture, high-resolution computed tomography (HRCT), and symptoms were assessed.

RESULTS

Treatment response rates (and median response times) were 44% (2 mo or longer) for culture, 60% (5.5-11.5 mo) for HRCT, and 53% (8.5 mo) for symptoms. Having noncavitary, compared with cavitary, disease increased culture response by 4.0 times (95% confidence interval [CI], 1.7-9.2) and HRCT response by 4.9 times (95% CI, 1.9-13.0). Culture response was 1.5 times (95% CI, 1.1-2.2) higher for older subjects and 2.2 times (95% CI, 1.0-4.7) higher for previously untreated subjects. Being smear-negative increased culture response by 2.3 times (95% CI, 1.1-5.2) but decreased HRCT response by 4.4 times (95% CI, 1.7-11.5). Increasing ethambutol use by 5 mo increased culture response by 1.5 times (95% CI, 1.0-2.1) but decreased symptom response. Not having chronic obstructive pulmonary disease, bronchiectasis, or poor lung function increased symptom response by 1.9 to 3.9 times.

CONCLUSIONS

TIW therapy was less effective for MAC-PD patients with cavitary disease and a history of chronic obstructive pulmonary disease, bronchiectasis, or previous treatment for MAC-PD. Further research is needed to study the long-term outcomes of TIW treatment.

High-resolution computed tomography of 'hot tub' pneumonitis

A case of pneumonitis following exposure to Mycobacterium avium intracellulare in an indoor home spa (hot tub) is presented. The patient complained of recurrent dyspnoea and wheezing. High-resolution CT showed centrilobular ground-glass nodules. Pathological correlation showed interstitial and bronchiolocentric granulomata. Biopsy cultures grew M. avium intracellulare. The patient condition improved following cessation of hot tub use.

[Clinicoradiological diagnosis of respiratory infections: estimate of pathogens by radiological findings and the strategy for treatment]

This review discusses the clinicoradiological findings of community-acquired respiratory infections and the treatment strategy for respiratory infections. To make a differential diagnosis between bacterial pneumonia, pneumonia caused by atypical pathogens, and mycobacterial infections, it is very important to analyze the radiological findings of inflammatory lung diseases based on normal antomical structures. If clinicoradiological anlyses could make these differentiations, the appropriate treatment strategy for respiratory infections could be established. To accomplish this, exact orientations of pulmonary lobulus, acinus, and respiratory bronchioles is very important. Then, through analyzing chest CT findings and distribution patterns based on normal anatomical structures, estimation of causative pathogens could be possible. Especially, whether inflammatory exudates could pass Kohn's pores as well as Lambert's channel or not is very important factor to affect radiological findings of several pneumonia (as traditionally called "segmental" and "nonsegmental" distribution). To differentiate infections caused by Mycobacterium tuberculosis from nontuberculous mycobacteria, several important criteria have been demonstrated. Briefly, it has been suggested that Mycobacterium avium complex (MAC) respiratory infection is increasing especially in elderly women without underlying diseases. In MAC respiratory infection, right middle lobe and left lingula are frequently involved and centrilobular nodules and diffuse bronchiectases are characteristic radiological findings. Finally, the role of telithromycin in the treatment of respiratory infections is discussed.

Drug-sensitive tuberculosis, multidrug-resistant tuberculosis, and nontuberculous mycobacterial pulmonary disease in nonAIDS adults: comparisons of thin-section CT findings

The aim of this work was to compare thin-section CT (TSCT) findings of drug-sensitive (DS) tuberculosis (TB), multidrug-resistant (MDR) TB, and nontuberculous mycobacterial (NTM) pulmonary disease in nonAIDS adults. During 2003, 216 (113 DS TB, 35 MDR TB, and 68 NTM) patients with smear-positive sputum for acid-fast bacilli (AFB), and who were subsequently confirmed to have mycobacterial pulmonary disease, underwent thoracic TSCT. The frequency of lung lesion patterns on TSCT and patients' demographic data were compared. The commonest TSCT findings were tree-in-bud opacities and nodules. On a per-person basis, significant differences were found in the frequency of multiple cavities and bronchiectasis (P < 0.001, chi-square test and multiple logistic regression analysis). Multiple cavities were more frequent in MDR TB than in the other two groups and extensive bronchiectasis in NTM disease (multiple logistic regression analysis). Patients with MDR TB were younger than those with DS TB or NTM disease (P < 0.001, multiple logistic regression analysis). Previous tuberculosis treatment history was significantly more frequent in patients with MDR TB or NTM disease (P < 0.001, chi-square test and multiple logistic regression analysis). In patients with positive sputum AFB, multiple cavities, young age, and previous tuberculosis treatment history imply MDR TB, whereas extensive bronchiectasis, old age, and previous tuberculosis treatment history NTM disease.

[Clinical studies on the pathogenetic factors of cavitary and nodular bronchiectatic types in pulmonary Mycobacterium avium complex disease]

We investigated the clinical, laboratory and radiological findings of 273 newly diagnosed cases of pulmonary Mycobacterium avium complex (MAC) disease, who were diagnosed in our hospital during 7 years from January 1996 to December 2002. Radiological findings of all cases were classified at the time of diagnosis into 2 patterns, the cavitary (Cav) type and the nodular bronchiectasis (NB) type. Clinical and laboratory findings at the time of diagnosis of 44 death cases were compared with those of 273 newly diagnoses cases, to analyze the prognostic factors of this disease. MAC disease cases showed a marked increase in number in recent years, but only in women. Mean age at the first visit was 65.7 years in men and 63.2 years in women, and when limited to fatal cases, it was 72.3 years in men and 69.4 years in women. Low body weight in terms of body mass index (BMI) and moderately low serum albumin level were found at the time of the first hospital visit in all the newly diagnosed and death cases. In the fatal cases, the peripheral blood lymphocyte counts revealed a relatively smaller number than the normal range, and the PPD skin test showed a negative reaction in 57.7% of all cases, suggesting the presence of lowered cell-mediated immunity at the time of diagnosis. Whether malnutrition occurs as a result of MAC disease or the individuals with lower nutrition level are easy to develop to MAC disease remains to be clarified. In regard to radiological findings, many cavitary (Cav) type cases were found in men and nodular bronchiectasis (NB) type in women among newly diagnosed cases, while the cavitary type was observed in many in both men and women fatal cases. The mean duration period from diagnosis to death was 28.3 months in men and 60.2 months in women, showing a longer survival after diagnosis, perhaps due to earlier hospital visits by women. The average age at death was 74.4 years old in men and 73.8 years old in women, and the two radiological patterns did not change throughout the entire disease course.

Relationship between clinical efficacy of treatment of pulmonary Mycobacterium avium complex disease and drug-sensitivity testing of Mycobacterium avium complex isolates

We prospectively investigated the relationship between the clinical efficacy of treatment of pulmonary Mycobacterium avium complex (MAC) disease and drug-sensitivity testing of MAC isolates for antituberculous drugs, new quinolone antibiotics, and clarithromycin (CAM). Fifty-two patients who satisfied the diagnostic criteria of the American Thoracic Society (ATS) and who received treatment between April 1998 and December 2005, using combined therapy of rifampicin (RFP), ethambutol (EB), streptomycin (SM), and CAM, were enrolled in this study. The causative microorganisms isolated were Mycobacterium avium in 30 patients and M. intracellulare in 22 patients. Although separation of the two strains showed drug sensitivity testing to have slightly better minimal inhibitory concentrations (MIC) for M. intracellulare than for M. avium, there were no significant differences in the sputum eradication rate or clinical improvement between the two strains. The MICs of various antibiotics for the isolated MAC strains were as follows: RFP, 0.125-8 microg/ml; CAM, 0.25-16 microg/ml; SM, 2-128< or =microg/ml; EB, 128< or = microg/ml; levofloxacin (LVFX), 1-32 microg/ml; sparfloxacin (SPFX), 0.5-16 microg/ml; and gatifloxacin (GFLX), 0.25-8 microg/ml. The isolated MAC strains showed the same excellent drug sensitivity test results for RFP, new quinolones, and CAM, but they showed resistant drug-sensitivity results for EB and SM. Regarding the relationship between clinical efficacy and the MICs of RFP, EB, CAM, and SM, there was a good relationship only for CAM. Although the ATS has not yet recommended routine drug susceptibility testing of CAM, we believe that drug susceptibility testing of CAM should be performed before the initial treatment is undertaken for pulmonary MAC disease.

Fatal hemoptysis from invasiveAspergillus nigerin a patient with cavitary lung disease andMycobacterium avium complexinfection

Invasive aspergillosis typically afflicts immunocompromised patients, whereas pulmonary aspergilloma is a recognized complication of pre-existing cavitary lung disease in immunocompetent hosts. In both cases, the most prevalent pathogens are Aspergillus fumigatus and Aspergillus flavus. We describe a case of fatal hemoptysis from invasive Aspergillus niger infection in the setting of bullous lung disease, steroid-treated sarcoidosis, and Mycobacterium avium complex infection. This report highlights the potential for A. niger to cause invasive disease in conjunction with other pathologic processes in the lung.

Non-tuberculous mycobacteria in patients with bronchiectasis

BACKGROUND

Non-tuberculous mycobacteria (NTM) are ubiquitous environmental organisms. Patients with pre-existing lung damage are susceptible to NTM, but their prevalence in bronchiectasis is unknown. Distinguishing between lung colonisation and disease can be difficult.

METHODS

A prospective study of 100 patients with bronchiectasis was undertaken to evaluate the prevalence of NTM in sputum, and a retrospective analysis of clinical, microbiological, lung function and radiology data of our clinic patients with NTM sputum isolates over 11 years was performed.

RESULTS

The prevalence of NTM in this population of patients with bronchiectasis was 2%. Patients in the retrospective study were divided into three groups: bronchiectasis+multiple NTM isolates (n=25), bronchiectasis+single isolates (n=23), and non-bronchiectasis+multiple isolates (n=22). Mycobacterium avium complex (MAC) species predominated in patients with bronchiectasis compared with non-bronchiectasis lung disease (72% v 9%, p<0.0001). Single isolates were also frequently MAC (45.5%). Multiple isolates in bronchiectasis were more often smear positive on first sample than single isolates (p<0.0001). NTM were identified on routine screening samples or because of suggestive radiology. No particular bronchiectasis aetiology was associated with an NTM. Pseudomonas aeruginosa and Staphylococcus aureus were frequently co-cultured. Six (25%) of multiple NTM patients had cavities of which five were due to MAC. Half the patients with multiple isolates were treated, mostly due to progressive radiology.

CONCLUSIONS

NTM are uncommon in non-cystic fibrosis bronchiectasis. Routine screening identifies otherwise unsuspected patients. MAC is the most frequent NTM isolated.