A case of pneumonia caused by Mycobacterium avium complex successfully treated with clarithromycin

We reported on a 79-year-old woman with pneumonia caused by Mycobacterium avium complex (MAC). She was admitted with fever, general fatigue, and cough. A chest X-ray film showed infiltrative shadows in the right lung field. In spite of administration of conventional antibiotics, the infiltrative shadows enlarged. A chest CT scan revealed areas of consolidation and ground glass opacities. Bronchoalveolar lavage (BAL) examination revealed an increased number of lymphocytes. Transbronchial lung biopsy revealed many granulomatous regions with giant cells. Mycobacterium intracellulare was found in the culture of BAL fluid and identified by PCR. Treatment was started with rifampicin, ethambutol, and clarithromycin. However, rifampicin and ethambutol were soon discontinued because of severe anorexia. Her symptoms and the radiographic appearance markedly improved following treatment of clarithromycin alone. Subsequently small doses of rifampicin and ethambutol were restarted because her general condition was much improved. These findings suggest that clarithromycin is an effective and tolerable agent for elderly patients with MAC.     

A case of infected bulla caused by Mycobacterium kansasii]

A 62-year-old man was referred to our hospital because of persistent sub-fever. A pulmonary fungal infection was suspected owing to the elevation of the serum-D-glucan level. Since a chest radiograph and a CT scan revealed intrabullous fluid in the right upper lobe, percutaneous needle aspiration was performed. Although acid-fast bacilli smears of the sputum and intrabullous fluid were negative, their cultures were found to be positive thereafter. M. kansasii was isolated and identified. After chemotherapy with antituberculous drugs, sub-fever improved and intrabullous fluid disappeared completely. Infected bulla caused by mycobacteria is very rare.     

A case of infected bulla caused by Mycobacterium gordonae]

A 65-year-old man was admitted to Tokyo Metropolitan Geriatric Medical Center because of dyspnea on effort, loss of appetite and general fatigue. Chest radiography on admission showed niveau formation in, and infiltration around, the bulla. Percutaneous drainage of the intrabullous fluid was performed and Mycobacterium gordonae was repeatedly cultured from it. The patient was treated with RFP, INH and CAM and the intrabullous fluid and infiltration around the bulla was markedly improved. Seven cases of pulmonary infection by M. gordonae have been reported in Japan, but this is the first case of bulla infected by this organism.     

Diagnosis of disease caused by Mycobacterium avium complex

Isolation of Mycobacterium avium complex from sputum specimens in association with the appearance of a new cavitary (or infiltrative) lesion was studied in 299 patients from whom the organism was isolated one or more times. Of the patients studied, 114 showed only single isolation. Of these 114, only two patients (2 percent) had association with appearance of a cavitary lesion. Of 29 patients who showed two isolations, 26 (90 percent) had the association. Of 40 patients who showed three isolations, 39 (98 percent) had the association. All 116 patients who showed four or more isolations had the association with appearance of a cavitary lesion. Accordingly, of a total of 185 patients who showed two or more isolations, 181 (98 percent) had the association. Of these 181, 176 (97 percent) showed two or more isolations in the sputum examinations made in the initial three days. Therefore, the sputum examination in the first three days after onset of disease is most important for the diagnosis of disease caused by Mycobacterium avium complex. Since the probability that casual isolation of the organism occurs twice is extremely low, we can make the diagnosis of pulmonary infection caused by this organism by evidence of two or more isolations of the organism in the first few days after the onset of disease, which is associated with appearance of a new cavitary (or infiltrative) lesion. Moreover, theoretical consideration made in this study has led us to conclude that patients who have had a single isolation of the organism together with a new cavitary lesion should be regarded as having an infection.     

A case of hypersensitivity pneumonitis caused by inhalation of Mycobacterium avium from a home bath with a circulating water system]

A 26-year-old man presented with complaints of exertional dyspnea and cough. The patient has already been given corticosteroids at a previous hospital. Chest CT revealed small centrilobular nodules with diffuse ground-glass opacities in both lungs. Lung biopsy specimens at thoracoscopy revealed non-necrotizing granulomas, patchy foci of mononuclear cell infiltration and fibrous thickening of alveolar septa, and Masson's bodies in bronchioles. Sputum culture showed the growth of Mycobacterium avium complex (MAC). Culture of water from the bath tub of his home showed MAC. Administration of antituberculous drugs and corticosteroids, and avoidance of bathing at home resulted in the improvement of his symptoms and CT findings. We believe the case is hypersensitivity pneumonitis to MAC in an immunocompetent patient, simulating hot tub lung. Hypersensitivity pneumonitis caused by MAC is rare in Japan.     

A case of pulmonary Mycobacterium avium infection with a rapid-growing solitary node]

A 72-year-old man was admitted to our hospital because of an abnormal shadow on his chest radiograph. Computed tomography revealed a 3 cm solitary nodular opacity in the right S1. Bronchofiberscopy could neither give any specific histological findings nor bacteriological findings. This nodular shadow increased in size to 1.5 times that in the first chest radiograph. In addition, since there was no abnormal finding in the chest radiograph one year before, we performed partial pulmonary resection by video-assisted thoracoscopic surgery, taking into consideration the possibility that the solitary node was malignant. The pathological findings of the resected specimen were an epitheloid cell granuloma with Langhans giant cell and caseous necrosis. We could not detect any acid-fast bacilli or malignant cells. After surgery, M. avium was detected in a 6-week culture of the resected specimen. We treated the patient with RFP, EB and CAM for 6 months. Outpatient follow-up revealed no relapse.     

Medical management of pulmonary disease caused by Mycobacterium avium complex

The current medical therapy for Mycobacterium avium complex is controversial. American Thoracic Society recommendations advocate empiric therapy with drug susceptibility testing only for clarithromycin. At National Jewish, where we mainly see cases complicated by treatment failure and drug intolerance, we use in vitro susceptibility testing and therapeutic drug monitoring to optimize efficacy and reduce toxicity.     

Pathological findings of bronchiectases caused by Mycobacterium avium intracellulare complex

It has been argued whether bronchiectasis is truly caused by MAC infection or just a predisposed condition in which MAC colonizes. Our present study was designed to evaluate the pathological findings of bronchiectases caused by Mycobacterium avium intracellulare complex (MAC) lung infection and to demonstrate MAC in the lesion of bronchiectases. A retrospective study was performed in nine cases with positive cultures for MAC in whom lung resections were performed. A determination of whether or not MAC caused pulmonary disease was made using the 1997 criteria required by the American Thoracic Society. In addition, MAC were cultured from all nine lung specimens. Pathological findings of bronchiectases were evaluated in these nine patients. Destruction of bronchial cartilage and smooth muscles layer, obstruction of airway by granulomas, and ulceration of bronchial mucosa were frequently observed. Our present study demonstrates that destruction of fundamental bronchial structure due to extensive granuloma formation throughout the airways was likely the main cause of bronchiectases in MAC infection.     

Comparison of prognosis of pulmonary diseases caused by Mycobacterium avium and by Mycobacterium intracellulare.

A total of 55 patients with pulmonary disease caused by Mycobacterium avium and by Mycobacterium intracellulare were compared for their prognosis. Causative mycobacteria were identified by the DNA probes (Gen-Probe) method. Of the 55 patients, 28 had pulmonary disease caused by M avium and the remaining 27, by M intracellulare. Of the former group, four patients had progressive disease, and three of them died during the observation period. In contrast, only one of the latter group had progressive disease. On the other hand, only one of the former group was cured. In contrast, six of the latter group were cured, showing the closure of cavity and the disappearance of mycobacteria from the sputum. The prognosis of pulmonary disease caused by M avium appears to be worse than that caused by M intracellulare.     

A case of pulmonary Mycobacterium avium complex disease, mimicking hot tub lung]

A 56-year-old man in whom reticulonodular shadows had been noted on a previous chest radiography study was admitted to our hospital with complaint of exertional dyspnea in March 2004. His thoracic computed tomography (CT) showed diffuse ground-glass opacities and multiple centrilobular small nodules in both lung fields. Lymphocytes occupied a high proportion in the cells recovered from the bronchoalveolar lavage fluid. These findings were compatible with those for hypersensitivity pneumonitis. Histopathological findings observed in the video-assisted thoracoscopic surgical biopsy specimens included necrotizing granulomas, organizing pneumonia associated with collective epithelioid cell granulomas without necrosis, and alveolar septal thickening with lymphocyte infiltration that showed a centrilobular distribution. These findings were also compatible with those for hot tub lung. Further information that supported the diagnosis were the identifications of Mycobacterium avium complex in his sputum by acid-fast bacteriological culture as well as positive for Mycobacterium avium polymerase chain reaction in lung specimen. He responded well to corticosteroid therapy, resulting in improvement in his clinical condition as well as in his chest radiographs. He was later put on an antituberculosis therapy, and the corticosteroid therapy was discontinued. This led to an exacerbation of his disease and corticosteroid therapy was restarted. It is not long time since the disease was first recognized, and thus few cases have been reported in Japan. Our report may provide valuable information on the disease in this country.     

A case of pulmonary infection caused by Mycobacterium szulgai

We report a case of pulmonary non-tuberculous mycobacteriosis caused by Mycobacterium szulgai. A thirty-nine-year-old man with no relevant significant past history underwent an annual medical check. His chest X-ray and CT scan showed an infiltrative shadow with a cavity in the right upper lobe. As it was suggestive of pulmonary tuberculosis, he was referred to our hospital. Smear tests of his sputum, gastric fluid, and transbronchial fluid showed no mycobacterial organisms, but culture of the samples revealed growth of mycobacteria. The organism was identified as M. szulgai using a DNA-DNA hybridization method, and the case was diagnosed as pulmonary non-tuberculous mycobacteriosis caused by M. szulgai. By anti-mycobacterial drug treatment with isoniazid, rifampicin, and ethambutol, the infiltrative shadow on chest roentogenogram and CT showed improvement. Culture of his sputum and gastric fluid showed no growth of mycobacteria after starting treatment.     

A four-drug regimen for initial treatment of cavitary disease caused by Mycobacterium avium complex

Forty-six patients with positive sputum cultures for Mycobacterium avium complex and cavitary disease were placed on a 4-drug regimen consisting of isoniazid, rifampin, and ethambutol daily and streptomycin twice weekly. Forty-two (91.3%) converted their sputum to negative and 4 (8.7%) failed to convert. All of the 4 nonconverters had prior subtotal gastrectomy. Twenty-two patients were available for long-term follow-up: 12 patients completed 24 months of chemotherapy, all experienced sputum conversion, but 2 reactivated, 1 at 9 and the other at 27 months after termination of chemotherapy. These 2 patients had prior subtotal gastrectomy. Ten patients completed 18 months of chemotherapy with sputum conversion, 2 of these reactivated but had not had prior subtotal gastrectomy. In this group of patients, subtotal gastrectomy appeared to be an adverse risk factor for both initial treatment response and reactivation in pulmonary disease caused by Mycobacterium avium complex.     

Pulmonary infection caused by Mycobacterium gordonae]

A 57-year-old woman who had been operated on for colon cancer and given chemotherapy, presented in September 1995 with worsening cough and abnormalities on her chest X-ray film. Acid-fast bacilli were isolated from the sputum. The organism was classified as M. gordonae by biochemical tests and DNA/DNA hybridization. The patient was treated with rifampicin and clarithromycin. Subsequently, sputum cultures became negative and the chest x-ray film showed a decrease infiltration. The findings in the present case suggest that M. gordonae may cause pulmonary infection and should be considered as an opportunistic pathogen.     

Pulmonary mycobacteriosis caused by Mycobacterium peregrinum: A case report

Rationale:Mycobacterium peregrinum is a member of the group of rapidly growing nontuberculous mycobacteria. It mainly causes surgical site and catheter-related infections, while pulmonary infection is rare. We herein present a case of pulmonary infection caused by M peregrinum.Patient concerns:A 62-year-old woman visited our hospital with dyspnea and was admitted for the treatment of pneumonia in July 2018.Diagnosis:Chest computed tomography showed patchy opacities and consolidation in the bilateral lungs and a cavity in the right upper lobe, which persisted after the treatment of bacterial pneumonia 5 years ago. She was administered ceftriaxone and azithromycin. Consolidation in the bilateral lungs improved, whereas the cavity in the right upper lobe remained and the consolidation surrounding it gradually spread. On admission, the sputum acid-fast bacillus culture was positive, and M peregrinum was identified twice by mass spectrometry. The cavity and consolidation surrounding it were diagnosed as pulmonary mycobacteriosis caused by M peregrinum.Interventions:Although we recommended treatment for mycobacteriosis, the patient refused it.Outcomes:The patient is regularly followed up; however, the cavity wall is thickening and shadows have become mildly enhanced over the course of 3 years.Lessons:We herein present a rare case of pulmonary mycobacteriosis caused by M peregrinum and discuss the literature. Since limited information is currently available on pulmonary mycobacteriosis caused by M peregrinum, the accumulation of further case reports and the clarification of its clinical features are needed.