Nontuberculous mycobacteria

Leung, Janice M.; Olivier, Kenneth N.

doi:10.1097/mcp.0b013e328365ab33

Cited by 85 publications

(27 citation statements)

References 94 publications

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“…Phenotypic testing for antibiotic resistance might be useful for guiding antibiotic treatment. However, except for clarithromycin resistance, the poor correlation between in vitro drug susceptibility results and clinical response to antibiotic treatment is of concern (36). Unambiguous detection of inducible clarithromycin resistance requires the sequencing of the erm(41) gene (21).…”

Section: Discussionmentioning

confidence: 99%

Characterization of Rough and Smooth Morphotypes of Mycobacterium abscessus Isolates from Clinical Specimens

et al. 2014

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Mycobacterium abscessus, which consists of the two subspecies M. abscessus subspecies abscessus and M. abscessus subspecies bolletii, can produce rough or smooth colony morphologies. Here we analyzed 50 M. abscessus isolates cultured from the respiratory specimens of 34 patients, 28 (82%) of whom had cystic fibrosis (CF), with respect to their colony morphologies and antibiotic susceptibilities. The overall proportions of occurrences of the two morphotypes were similar, with specimens from 50% of the patients showing a rough and 38% showing a smooth morphotype. A total of 12% of the specimens from the patients showed both morphotypes simultaneously. At the subspecies level, the proportions of rough and smooth morphotypes differed substantially; 88% of rough morphotypes belonged to M. abscessus subspecies abscessus, and 85% of smooth morphotypes belonged M. abscessus subspecies bolletii. Inducible clarithromycin resistance due to the Erm(41) methylase, as well as high-level resistance to clarithromycin due to mutations within the rrl gene, occurred independently of the morphotype. The MIC 50 s of amikacin and cefoxitin were identical for the two morphotypes, whereas the MIC 50 s of tigecycline were 0.25 g/ml for the rough morphotype and 2.0 g/ml for the smooth morphotype. Our results show that the smooth morphotype was more dominant in respiratory specimens from CF patients than previously thought. With respect to resistance, colony morphology did not affect the susceptibility of Mycobacterium abscessus to the first-line antibiotics clarithromycin, amikacin, and cefoxitin.T he genus Mycobacterium contains more than 100 different species which belong either to the Mycobacterium tuberculosis complex or to the large group of nontuberculous mycobacteria (NTMs). M. abscessus is an NTM, and clinical studies have begun to shed light on its epidemiology. M. abscessus is involved in soft tissue infections and is a dominant respiratory pathogen in patients with cystic fibrosis (CF). It is the second-most-common NTM species isolated from CF patients in the United States and the most common NTM species isolated from CF patients in Europe (1-6). Fatal infections with M. abscessus have been reported, especially after lung transplantation (7). M. abscessus has been subdivided in type I and type II, which, together with Mycobacterium chelonae, share identical 16S rRNA genes but show differences within the hsp65 gene (8, 9). Based on multilocus sequence analysis of hsp65, rpoB, secA, and the 16S-23S internal transcribed spacer (ITS) region, M. abscessus was further subdivided into three species, M. abscessus (sensu stricto), M. bolletii, and M. massiliense (10, 11). Recently, uniting M. bolletii and M. massiliense as M. abscessus subspecies bolletii (the former type II) and separating that subspecies from M. abscessus subspecies abscessus (the former type I) have been proposed (12).M. abscessus colonies on agar plates grow with either a rough or a smooth morphology (13,14). M. abscessus can show cord formation when visualized mic...

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Section: Discussionmentioning

confidence: 99%

Characterization of Rough and Smooth Morphotypes of Mycobacterium abscessus Isolates from Clinical Specimens

et al. 2014

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“…In this study, we sought to assess the performance of MALDI-TOF MS for subspecies-level typing of M. abscessus species because the present methods fail to enable accurate subspecies identification for the optimal clinical management of M. abscessus species infection (14).…”

Section: Discussionmentioning

confidence: 99%

“…bolletii (7,13). Moreover, chronic macrolide therapy was recently shown to favor the emergence of M. abscessus species (14), making it crucial to differentiate subspecies to optimize treatment. Noneradication may impair health status, preventing lung transplantation (15).…”

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confidence: 99%

Classification Algorithm for Subspecies Identification within the Mycobacterium abscessus Species, Based on Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry

Fangous

Mougari

Gouriou³

et al. 2014

J Clin Microbiol

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dMycobacterium abscessus, as a species, has been increasingly implicated in respiratory infections, notably in cystic fibrosis patients. The species comprises 3 subspecies, which can be difficult to identify. Since they differ in antibiotic susceptibility and clinical relevance, developing a routine diagnostic tool discriminating Mycobacterium abscessus at the subspecies level is a real challenge. Forty-three Mycobacterium abscessus species isolates, previously identified by multilocus sequence typing, were analyzed by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). A subspecies identification algorithm, based on five discriminating peaks, was drawn up and validated by blind identification of a further 49 strains, 94% of which (n ‫؍‬ 46) were correctly identified. Two M. abscessus subsp. massiliense strains were misidentified as M. abscessus subsp. abscessus, and for 1 other strain identification failed. Inter-and intralaboratory reproducibility tests were conclusive. This study presents, for the first time, a classification algorithm for MALDI-TOF MS identification of the 3 M. abscessus subspecies. MALDI-TOF MS proved effective in discriminating within the M. abscessus species and might be easily integrated into the workflow of microbiology labs.

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“…In the United States and some other parts of the world, it is the second most frequent pulmonary nontuberculous mycobacterial (NTM) infection (28%), after Mycobacterium avium complex, and its prevalence is increasing (6,7). MABSC causes significant mortality in the CF population.…”

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confidence: 99%

Clonal Diversification and Changes in Lipid Traits and Colony Morphology in Mycobacterium abscessus Clinical Isolates

et al. 2015

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fThe smooth-to-rough colony morphology shift in Mycobacterium abscessus has been implicated in loss of glycopeptidolipid (GPL), increased pathogenicity, and clinical decline in cystic fibrosis (CF) patients. However, the evolutionary phenotypic and genetic changes remain obscure. Serial isolates from nine non-CF patients with persistent M. abscessus infection were characterized by colony morphology, lipid profile via thin-layer chromatography and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), sequencing of eight genes in the GPL locus, and expression level of fadD23, a key gene involved in the biosynthesis of complex lipids. All 50 isolates were typed as M. abscessus subspecies abscessus and were clonally related within each patient. Rough isolates, all lacking GPL, predominated at later disease stages, some showing variation within rough morphology. While most (77%) rough isolates harbored detrimental mutations in mps1 and mps2, 13% displayed previously unreported mutations in mmpL4a and mmpS4, the latter yielding a putative GPL precursor. Two isolates showed no deleterious mutations in any of the eight genes sequenced. Mixed populations harboring different GPL locus mutations were detected in 5 patients, demonstrating clonal diversification, which was likely overlooked by conventional acid-fast bacillus ( MABSC causes serious chronic pulmonary infections in those with underlying conditions such as bronchiectasis or cystic fibrosis (CF). In the United States and some other parts of the world, it is the second most frequent pulmonary nontuberculous mycobacterial (NTM) infection (28%), after Mycobacterium avium complex, and its prevalence is increasing (6, 7). MABSC causes significant mortality in the CF population. In Scandinavian countries, one-fourth of CF patients who have persistently positive MABSC sputum cultures have received lung transplantation or died (8).Glycopeptidolipid (GPL) is the most abundant glycolipid in the outer cell envelope of MABSC, and its synthesis and transport are controlled by the GPL locus (9). A growing number of studies have linked the rough colony morphology in MABSC to loss of GPL, increased pathogenicity, and clinical decline in CF patients (10)(11)(12)(13)(14)(15)(16). While most studies of persistent MABSC infection focused on CF patients, less is known about MABSC in the non-CF population regarding presence of mixed populations, clonal relatedness, and phenotypic and genotypic changes of strains collected over time.We have very limited understanding of the evolutionary phenotypic and genetic changes occurring in MABSC during persistent human lung infection. We lack the fundamental knowledge needed to identify selective pressures associated with rough morphology and, once identified, how to reverse them. To address these questions, we collected serial clinical isolates of M. abscessus from non-CF patients with persistent pulmonary infection who were followed for 5 years or more and assessed strain relatedness and diversity, colony...

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Nontuberculous mycobacteria

Abstract: Given increasing prevalence rates, clinicians should maintain a high level of suspicion for NTM as disease-causing organisms in CF, particularly for M. abscessus. New knowledge regarding this species, however, can help to tailor appropriate therapy.

Cited by 85 publications

References 94 publications

Characterization of Rough and Smooth Morphotypes of Mycobacterium abscessus Isolates from Clinical Specimens

Characterization of Rough and Smooth Morphotypes of Mycobacterium abscessus Isolates from Clinical Specimens

Classification Algorithm for Subspecies Identification within the Mycobacterium abscessus Species, Based on Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry

Clonal Diversification and Changes in Lipid Traits and Colony Morphology in Mycobacterium abscessus Clinical Isolates

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