Clinical Significance of the Differentiation Between Mycobacterium avium and Mycobacterium intracellulare in M avium Complex Lung Disease

Koh, Won Jung; Jeong, Byeong‐Ho; Jeon, Kyeongman; Lee, Nam Yong; Lee, Kyung Soo; Woo, Sook Young; Shin, Sung Jae; Kwon, Oh‐Jung

doi:10.1378/chest.12-0494

Cited by 176 publications

(155 citation statements)

References 29 publications

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“…Unfortunately, during the study period, organisms identified as MAC or M. abscessus were not further subspeciated; nor was colony morphotype routinely reported as "smooth" or "rough." There have been recent data to suggest differing pathogenic potential between M. avium and M. intracellulare (42) and improved treatment response rates with M. bolletii (previously M. massilliense) infection compared with M. abscessus based on the presence of a nonfunctioning erythromycin ribosomal methylase gene (25), which may be a confounding factor that could be contributing to disease progression in our patients.…”

Section: Original Researchmentioning

confidence: 87%

Clinical Significance of a First Positive Nontuberculous Mycobacteria Culture in Cystic Fibrosis

et al. 2014

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Rationale: Little is known about outcomes of infection with nontuberculous mycobacteria (NTM) in cystic fibrosis (CF) or about the significance of a positive NTM culture. Determining which patients are at risk for active NTM disease is clinically valuable.Objectives: To examine the clinical course of subjects with CF with an initial positive NTM culture and identify characteristics associated with active NTM disease.Methods: We performed a retrospective study of pediatric and adult subjects with CF with at least one positive NTM culture at the Colorado CF Center from 2000 to 2010.Measurements and Main Results: Mycobacterium avium complex was the first identified NTM in the majority of subjects (73%). The frequency of growing a second NTM species was 26% at 5 years. Clinical characteristics and distribution of NTM species between pediatric and adult subjects were similar except for differences in baseline FEV 1 (89% vs. 71%; P , 0.001) and coinfection with Pseudomonas aeruginosa (33% vs. 55%; P = 0.04). Over 60% of subjects had transient or persistent infection but not active NTM disease. Subjects who developed active NTM disease were distinguished from those with transient or persistent infection, respectively, by FEV 1 at the time of first positive NTM culture (72% vs. 84 or 86%; P = 0.02) and FEV 1 decline in the prior year (25.8%/yr vs. 20.7%/yr [P = 0.009] or 20.4%/yr [P = 0.001]). Conclusions:The majority of patients with CF with a first positive NTM culture do not progress to active disease. Lower lung function and accelerated lung function decline appear to be indicators of the significance of an initial positive NTM culture.

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Section: Original Researchmentioning

confidence: 87%

Clinical Significance of a First Positive Nontuberculous Mycobacteria Culture in Cystic Fibrosis

et al. 2014

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“…intracellulare is a major cause of MAC lung disease in sev- (27). In contrast to the studies from the United States, Queensland, Australia, and Korea, previous studies from Japan reported that M. avium was the predominant cause of MAC lung disease (4).…”

Section: Discussionmentioning

confidence: 99%

Absence of Mycobacterium intracellulare and Presence of Mycobacterium chimaera in Household Water and Biofilm Samples of Patients in the United States with Mycobacterium avium Complex Respiratory Disease

et al. 2013

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f Recent studies have shown that respiratory isolates from pulmonary disease patients and household water/biofilm isolates of Mycobacterium avium could be matched by DNA fingerprinting. To determine if this is true for Mycobacterium intracellulare, household water sources for 36 patients with Mycobacterium avium complex (MAC) lung disease were evaluated. MAC household water isolates from three published studies that included 37 additional MAC respiratory disease patients were also evaluated. Species identification was done initially using nonsequencing methods with confirmation by internal transcribed spacer (ITS) and/or partial 16S rRNA gene sequencing. M. intracellulare was identified by nonsequencing methods in 54 respiratory cultures and 41 household water/biofilm samples. By ITS sequencing, 49 (90.7%) respiratory isolates were M. intracellulare and 4 (7.4%) were Mycobacterium chimaera. In contrast, 30 (73%) household water samples were M. chimaera, 8 (20%) were other MAC X species (i.e., isolates positive with a MAC probe but negative with species-specific M. avium and M. intracellulare probes), and 3 (7%) were M. avium; none were M. intracellulare. In comparison, M. avium was recovered from 141 water/biofilm samples. These results indicate that M. intracellulare lung disease in the United States is acquired from environmental sources other than household water. Nonsequencing methods for identification of nontuberculous mycobacteria (including those of the MAC) might fail to distinguish closely related species (such as M. intracellulare and M. chimaera). This is the first report of M. chimaera recovery from household water. The study underscores the importance of taxonomy and distinguishing the many species and subspecies of the MAC. P revious studies have suggested household water (especially from bathroom showers) as a source of the Mycobacterium avium complex (MAC), which causes chronic lung disease (1, 2, 3, 4, 5). Both M. avium and M. intracellulare have been recovered from sputum, sinus, and household or potable water samples in multiple countries, including the United States and Japan (1, 4-8). In the majority of these studies, either hybridization probe methods (AccuProbe; Hologic Gen-Probe, Inc., San Diego, CA) or a multiplex 16S rRNA gene PCR was used for identification (1, 5, 9, 10). Isolates positive with the MAC probe but negative with the species-specific M. avium and M. intracellulare probes are collectively referred to as MAC X species.Currently We recently completed a study of variable-number tandemrepeat (VNTR) typing of clinical isolates of M. intracellulare using ITS sequencing to confirm the species designation (7). We then began household water biofilm studies for some of our patients and performed species identification and VNTR genotyping for MAC isolates as needed.Preliminary studies suggested that respiratory isolates of M. intracellulare indeed belonged to that species based on ITS sequencing (7) but that biofilm isolates thought to be M. intracellulare were actually M. chimaera ...

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“…It has been documented that M. intracellulare is the more virulent of the two, and infections of M. intracellulare require more intensive treatment than those of M. avium (1,26). Although there is currently no recommendation for the routine separation of MAC isolates into M. avium and M. intracellulare, it could have important prognostic and therapeutic implications in the future.…”

Section: Discussionmentioning

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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Clinical Significance of the Differentiation Between Mycobacterium avium and Mycobacterium intracellulare in M avium Complex Lung Disease

Cited by 176 publications

References 29 publications

Clinical Significance of a First Positive Nontuberculous Mycobacteria Culture in Cystic Fibrosis

Clinical Significance of a First Positive Nontuberculous Mycobacteria Culture in Cystic Fibrosis

Absence of Mycobacterium intracellulare and Presence of Mycobacterium chimaera in Household Water and Biofilm Samples of Patients in the United States with Mycobacterium avium Complex Respiratory Disease

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

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