Pulmonary disease caused by rapidly growing mycobacteria: a retrospective study of 44 cases in Japan.
BACKGROUND
The features of pulmonary disease caused by rapidly growing mycobacteria (RGM) have not been sufficiently documented.


OBJECTIVE
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 Mycobacterium abscessus, 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.
Department of Respiratory Medicine, National Hospital Organization National Toneyama Hospital, Toyonaka, Japan. yanoy @ toneyama.go.jp
Yukihiro
Y
Yano
Seigo
S
Kitada
Masahide
M
Mori
Shinichi
S
Kagami
Takahiro
T
Taguri
Takeshi
T
Uenami
Yoshinobu
Y
Namba
Tsutomu
T
Yoneda
Soichiro
S
Yokota
Ryoji
R
Maekura
D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D005260:Female; D006801:Humans; D007564:Japan; D008171:Lung Diseases / Q000000981:diagnostic imaging* / Q000382:microbiology* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D009165:Mycobacterium Infections, Nontuberculous / Q000175:diagnosis* / Q000382:microbiology* / Q000628:therapy; D019907:Mycobacterium fortuitum; D011859:Radiography; D012189:Retrospective Studies; D012307:Risk Factors; D012907:Smoking