Nontuberculous mycobacteria: susceptibility pattern and prevalence rate in Shanghai from 2005 to 2008 / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>An increasing incidence of disease caused by nontuberculous mycobacteria (NTM) is being reported. The purpose of this study was to determine the isolation rates of NTM from various clinical specimens, and their antimicrobial susceptibility patterns, over a 4-year period in Shanghai.</p><p><b>METHODS</b>All NTM isolated between 2005 and 2008 at Shanghai Pulmonary Hospital, a key laboratory of mycobacteria tuberculosis in Shanghai, China, were identified with conventional biochemical tests and 16S rRNA gene sequencing. Antimicrobial susceptibility for all NTM was determined using the BACTEC MGIT 960 system.</p><p><b>RESULTS</b>A total of 21,221 specimens were cultured, of which 4868 (22.94%) grew acid fast bacilli (AFB), and 248 (5.09%) of the AFB were NTM. The prevalence rate of NTM was determined as 4.26%, 4.70%, 4.96% and 6.38% among mycobacteria culture positive samples in years 2005, 2006, 2007 and 2008 respectively. These data indicated that the prevalence rate has continuously increased. Sixteen different species of NTM were identified, the most commonly encountered NTM in Shanghai were M. chelonae (26.7%), followed by M. fortuitum (15.4%), M. kansasii (14.2%), M. avium-intracellulare complex (13.1%) and M. terrae (6.9%). The rare species identified were M. marinum, M. gastri, M. triviale, M. ulcerans, M. smegmatis, M. phlci, M. gordonae, M. szulgai, M. simiae, M. scrofulaceum and M. xenopi. The five most commonly identified NTM species showed high drug resistance to general anti-tuberculosis drugs, particularly, M. chelonae and M. fortuitum appear to be multi-drug resistance.</p><p><b>CONCLUSIONS</b>The prevalence of NTM in Shanghai showed a tendency to increase over the course of the study. The five most commonly isolated NTM species showed high drug resistance to first line anti-tuberculosis drugs.</p>

Surgical Treatment of Pulmonary Diseases Due to Nontuberculous Mycobacteria

Although the treatment of pulmonary diseases due to nontuberculous mycobacteria (NTM) requires the long-term use of antibiotics in combination, the treatment success rates are unsatisfactory. We evaluated the clinical characteristics and surgical outcomes of 23 patients with NTM lung diseases who had underwent pulmonary resection. The median age of the patients was 45 yr. Of the 23 patients, 10 had Mycobacterium avium-intracellulare complex infection, 12 had M. abscessus infection, and one had M. xenopi infection. The indications for surgery were antibiotic therapy failure (n=11), remnant cavitary lesion with high probability of relapse (n=8), and massive hemoptysis (n=4). The most common procedure was lobectomy (48%). Postoperative complications occurred in eight patients (35%), including postoperative pneumonia (n=3) and late bronchopleural fistula (n=2). Negative sputum culture conversion was achieved and maintained in all except two mortalities. Although it is associated with a relatively high complication rate, patients with NTM lung disease whose disease is localized to one lung and who can tolerate resectional surgery might be considered for surgery, if there has been poor response to drug therapy or if the patients develop significant disease-related complications such as hemoptysis.

Pulmonary Disease Caused by Mycobacterium xenopi: The First Case in Korea

Mycobacterium xenopi is a nontuberculous mycobacterium (NTM) that rarely causes pulmonary disease in Asia. Here we describe the first case of M. xenopi pulmonary disease in Korea. A 66-year-old man was admitted to our hospital with a 2-month history of productive cough and hemoptysis. His past medical history included pulmonary tuberculosis 44 years earlier, leading to a right upper lobectomy. Chest X-ray upon admission revealed cavitary consolidation involving the entire right lung. Numerous acid-fast bacilli were seen in his initial sputum, and M. xenopi was subsequently identified in more than five sputum cultures, using molecular methods. Despite treatment with clarithromycin, rifampicin, ethambutol, and streptomycin, the infiltrative shadow revealed on chest X-ray increased in size. The patient's condition worsened, and a right completion pneumonectomy was performed. The patient consequently died of respiratory failure on postoperative day 47, secondary to the development of a late bronchopleural fistula. This case serves as a reminder to clinicians that the incidence of NTM infection is increasing in Korea and that unusual NTM are capable of causing disease in non-immunocompromised patients.