Pulmonary Disease Caused by Rapidly Growing Mycobacteria: A Retrospective Study of 44 Cases in Japan.
ABSTRACT Background: The features of pulmonary disease caused by rapidly growing mycobacteria (RGM) have not been sufficiently documented. Objectives: To establish these features, we retrospectively evaluated 44 patients. Methods: We screened respiratory isolates at the National Toneyama Hospital (Osaka, Japan) between 2003 and 2007. Diagnosis was based on the latest guidelines of the American Thoracic Society. The patients were classified into 3 types according to their radiographic findings: fibrocavitary, nodular bronchiectatic and unclassified variant. Results: We obtained 1,348 nontuberculous mycobacteria respiratory isolates from 1,187 patients, including 119 RGM isolates from 100 patients. Forty-four of these 100 patients were definitively diagnosed with respiratory disease due to RGM. The most common pathogen was Mycobacteriumabscessus, which accounted for 65.9% of cases, followed by Mycobacterium fortuitum at 20.5%. There was a statistically significant difference in smoking history between patients infected with these 4 RGM species (excluding those with an unknown smoking history; p = 0.039). The overall evaluation of radiographic findings revealed 18.2% as fibrocavitary, 43.2% as nodular bronchiectatic and 38.6% as unclassified variants in these 44 patients. There was a significant difference in radiographic findings between the 4 RGM species (p = 0.002). There was also a significant difference in radiographic findings between M. abscessus and M. fortuitum infected patients (p = 0.022). Conclusions: Patients with M. abscessus seem to have less of a smoking history and more frequent nodular bronchiectatic radiographic patterns than patients with M. fortuitum. In contrast, fibrocavitary patterns might be more frequent with M. fortuitum infection.
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ABSTRACT: A 70-year-old woman with methotrexate (MTX)-refractory rheumatoid arthritis (RA) was referred to our hospital for introduction of biological therapy. On high-resolution computed tomography scans, the patient exhibited abnormal findings such as bronchiectasis and centrilobular small nodules, which were highly suggestive of pulmonary nontuberculous mycobacterial (NTM) disease. Although mycobacterial cultures of sputum specimens yielded negative results, cultures of bronchoalveolar lavage fluids grew Mycobacterium abscessus. Frequent follow-up chest radiographs indicated that the patient's pulmonary disease became rapidly worse in 1 month following dose escalation of MTX and administration of low-dose prednisolone. Oral clarithromycin and levofloxacin, chosen on the basis of in vitro susceptibility testing, led to a dramatic recovery from this potentially life-threatening complication. Through our experience with this case, we have learned that (1) pulmonary M. abscessus disease can progress rapidly, even during nonbiological anti-RA therapy; (2) regular follow-up chest radiographs are useful to ensure timely implementation of anti-NTM treatment; (3) bronchoscopic testing should be considered when patients are suspected of pulmonary NTM disease but do not meet the diagnostic criteria; and (4) early isolation, identification, and susceptibility testing of causative NTM species are critical for favorable outcomes.Journal of Infection and Chemotherapy 02/2013; · 1.38 Impact Factor
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ABSTRACT: Species identification of nontuberculous mycobacteria (NTM) is challenging due to the increasing number of identified NTM species and the lack of standardized testing strategies. The objectives of this study were to investigate the distribution of NTM species recovered from respiratory specimens by multi-gene sequence-based typing and to evaluate the clinical significance of identified species. Two hundred and thirty-two consecutive clinical NTM isolates were subjected to sequencing of multiple genes, including hsp65, rpoB and ITS. In addition, clinical data from all patients whose specimens had NTM isolates were analyzed to examine clinical virulence and treatment history. Eighteen strains from 227 isolates of 169 patients were successfully identified at the species level by multi-gene sequence-based typing. Mycobacterium avium complex and M. abscessus complex made up the majority of isolated NTM (88%, 199/227), followed by M. fortuitum complex (4%, 10/227). The pathogenic potential of NTM differs enormously by species, and M. avium complex and M. abscessus complex revealed especially high virulence compared with other NTM species. The results from our work support that M. avium complex and M. abscessus complex were the most common NTM species with highly pathogenic potential isolated from clinical respiratory specimens and could be a good resource for molecular epidemiology of NTM species in Korea.Journal of clinical microbiology 02/2014; · 4.23 Impact Factor