Nontuberculous Mycobacteria Isolated from Respiratory Specimens during Recent Two Years: Distribution and Clinical Significance

Lee, Min Kyoung; Seo, Yiel Hea; Jeong, Ji Hoon; Park, Pil Whan; Kim, Kyung Hee; Ahn, Jeong Yeal; Kim, Jin Yong; Park, Jeong Woong

doi:10.5145/kjcm.2012.15.3.98

Cited by 5 publications

(3 citation statements)

References 20 publications

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“…In 1970, Kim et al30 identified NTM species in sputum at a rate of 2.7%. More recently, NTM isolation rates in cultured specimens have been found to be approximately 10-30%, as represented by those from Seoul Asan Hospital32 (21.9%) in 2002, Seoul National University (SNU) Hospital9 (21.5%) in 2006, Fatima Hospital33 (7.9%) in 2009, and Gil Hospital34 (19.4%) in 2012. The variation in rates reported by different hospitals may be due to variations in patient group characteristics, research periods, specimen collection and detection methods used, and NTM detection thresholds.…”

Section: Discussionmentioning

confidence: 99%

Identification and Distribution of Nontuberculous Mycobacteria from 2005 to 2011 in Cheonan, Korea

Kim

Rheem

2013

Tuberc Respir Dis

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BackgroundNontuberculous mycobacteria (NTM) are considered opportunistic pathogens, and several species of NTM are associated with human diseases that typically involve the pulmonary, skin/soft tissue, or lymphatic systems; such infection may also cause disseminated diseases. Recent studies have reported increasing rates of NTM-induced disease worldwide.MethodsRespiratory samples are being analyzed for acid-fast bacilli (AFB) culture and NTM identification at Dankook University Hospital in Cheonan, Korea, from September 2005 to September 2011. Identification is performed by using polymerase chain reaction-restriction fragment length polymorphism analysis targeting a novel region of the rpoB gene.ResultsA total of 25,133 specimens were received for AFB culture, of which 1,014 (4.0%) were NTM-positive. A total of 267 samples from 186 patients were tested for NTM identifications, and 232 samples from 157 patients were positive for NTM species. Among the patients who tested positive for NTM, 65.6% were men and the average age was 63.3 years. Mycobacterium avium complex, the most commonly detected NTM pathogen, was found in 65.9% of the 232 samples. The annual average percentage of NTM isolates from AFB culture-positive specimens was 31.3%: the highest rate was seen in 2011 (44.3%), followed by 2009 (37.4%) and 2010 (37.2%). An upward trend in NTM incidence was found during the study period.ConclusionThe prevalence of pulmonary NTM isolates continues to increase in Cheonan, suggesting that pulmonary NTM disease is becoming increasingly common.

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Section: Discussionmentioning

confidence: 99%

Identification and Distribution of Nontuberculous Mycobacteria from 2005 to 2011 in Cheonan, Korea

Kim

Rheem

2013

Tuberc Respir Dis

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“…Since the 2000s, the frequency of NTM isolation has been reported to be 12 to 38% of mycobacterial culture-positive specimens, and the number of patients with NTM disease has also been considerable, with a frequency of 8 to 49% of isolated NTM (8)(9)(10)(11)(12)(13)(14)(15). The isolation of NTM species from respiratory specimens is not sufficient evidence for the diagnosis of clinically significant NTM lung disease, since there are also clinical, radiographic, and microbiological criteria (1).…”

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confidence: 99%

Distribution of Nontuberculous Mycobacteria by Multigene Sequence-Based Typing and Clinical Significance of Isolated Strains

et al. 2014

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bSpecies 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 multigene sequence-based typing and to evaluate the clinical significance of identified species. Two hundred thirty-two consecutive clinical NTM isolates were subjected to sequencing of multiple genes, including hsp65, rpoB, and 16S-23S rRNA internal transcribed spacer (ITS) sequence. 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 from 169 patients were successfully identified at the species level by multigene 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 levels of virulence compared with findings for other NTM species. The results from our work support M. avium complex and M. abscessus complex being 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 South Korea.A ll members of the genus Mycobacterium, excepting M. tuberculosis and M. leprae, are considered nontuberculous mycobacteria (NTM) and are frequently isolated from environmental sources, including surface or tap water and soil (1). Currently, more than 160 mycobacterial species/subspecies are listed in the Genus Mycobacterium database (http://www.bacterio.cict.fr/m /mycobacterium.html; accessed on 22 August 2013), and the number of newly identified NTM is increasing. Recent data suggest that the incidence of lung disease caused by NTM with or without predisposing risk factors has been growing worldwide (2-6). However, epidemiologic data on the distribution and clinical significance of NTM lung disease are still scarce because NTM lung disease is not a reportable condition in most countries.In South Korea, NTM was first described as a cause of mycobacterial lung disease in 1981 (7); since then, the frequency of isolation of NTM from clinical specimens has shown a continuous increase. Since the 2000s, the frequency of NTM isolation has been reported to be 12 to 38% of mycobacterial culture-positive specimens, and the number of patients with NTM disease has also been considerable, with a frequency of 8 to 49% of isolated NTM (8-15). The isolation of NTM species from respiratory specimens is not sufficient evidence for the diagnosis of clinically significant NTM lung disease, since there are also clinical, radiographic, and microbiological criteria (1).Recently, various genotype-based methods for the identification of NTM have been developed to ra...

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“…1,13 Our study showed a higher frequency of NTM isolation (43.9%) compared with previous studies, which reported 2-20%. 19,20 There may be several reasons for this result. First, the infection rates of NTM are increasing, 21 and patients in this study received routine sputum or respiratory specimen culture tests.…”

Section: Discussionmentioning

confidence: 98%

Factors associated with radiologic progression of non‐cystic fibrosis bronchiectasis during long‐term follow‐up

et al. 2016

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Background and objective: Non-cystic fibrosis (CF) bronchiectasis is a chronic airway inflammatory disease, exhibiting a diverse array of clinical courses. The purpose of this study was to determine the factors that predict radiologic progression of non-CF bronchiectasis during a long-term follow-up. Methods: We reviewed the electronic medical records that included pulmonary function test data from non-CF bronchiectasis patients, who were older than 18 years of age with a follow-up of computerized tomography for more than 5 years. The original Bhalla score was used to determine the radiologic severity of non-CF bronchiectasis. Results: A total of 155 patients (mean age, 59.6 years; male, 45.2%) were included for the final analysis. The mean follow up time was 7.11 ± 1.42 (5-10) years. The baseline Bhalla score was 9.52 ± 3.14 (4-19), and the change of Bhalla score was 0.55 ± 1.14 (À2 to 5). The Bhalla score was increased in 56 patients (36.1%) but not in 99 patients (63.9%). The Bhalla score change was significantly associated with the age at diagnosis (p = 0.037), body mass index (BMI, p = 0.012), chronic infection of Pseudomonas aeruginosa (p = 0.005) or isolation of nontuberculous mycobacterium (p = 0.042) in respiratory specimens. In a multivariate analysis, BMI and isolation of P. aeruginosa were significantly related with the Bhalla score change. Conclusion: The radiologic progression of non-CF bronchiectasis was associated with lower BMI and isolation of P. aeruginosa in respiratory specimens.

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Nontuberculous Mycobacteria Isolated from Respiratory Specimens during Recent Two Years: Distribution and Clinical Significance

Cited by 5 publications

References 20 publications

Identification and Distribution of Nontuberculous Mycobacteria from 2005 to 2011 in Cheonan, Korea

Identification and Distribution of Nontuberculous Mycobacteria from 2005 to 2011 in Cheonan, Korea

Distribution of Nontuberculous Mycobacteria by Multigene Sequence-Based Typing and Clinical Significance of Isolated Strains

Factors associated with radiologic progression of non‐cystic fibrosis bronchiectasis during long‐term follow‐up

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