Utility of the MALDI-TOF MS method to identify nontuberculous mycobacteria

Kodana, Masahiro; Tarumoto, Norihito; Kawamura, Tohru; Saito, Taeko; Ohno, Hideaki; Maesaki, Shigefumi; Ikebuchi, Kenji

doi:10.1016/j.jiac.2015.09.006

Cited by 29 publications

(22 citation statements)

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“…These findings were similar to those from the study by Koh et al in which M. abscessus was found to be the second most common pathogen responsible for lung diseases caused by NTM, after MAC in the Republic of Korea [18, 19]. The identification of bacterial species is clinically important because treatment and response rates differ depending on the bacterial species, and some are refractory disease [20]. …”

Section: Discussionsupporting

confidence: 87%

Nontuberculosis mycobacterial infections at a specialized tuberculosis treatment centre in the Republic of Korea

Yoon

Choi

2017

BMC Infect Dis

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BackgroundThe incidence of nontuberculous mycobacteria (NTM) infections is increasing worldwide, however formal evaluations of the epidemiology of NTM infections are limited. Understanding the trends and true prevalence of NTM is a major priority for optimizing infection control programmes and resources. The purpose of this study was to investigate the epidemiology, clinical manifestations, and radiologic findings in NTM-infected patients at specialized Tuberculosis (Tb) treatment centre in South Korea, which is endemic to Tb, and find solutions to control NTM infections.MethodsA retrospective descriptive study was conducted among patients who were diagnosed with NTM from November 2011 to January 2016 at Seoul Metropolitan Government Seobuk hospital, Korea, using medical records and chest radiography results. Prevalence of NTM using national health insurance data was compared to the prevalence and incidence of Tb using National statistics data.ResultsThe age- and sex- adjusted prevalence of NTM infection per 100,000 population increased between 2009 (9.4) and 2016 (36.1). However, the prevalence and incidence of Tb per 100,000 population decreased from 106.5 to 74.4, and 81.2 to 61.8, respectively. In total, 64 patients (37 [57.8%] men) were enrolled in the study. Among 33 (51.6%) patients with slowly growing nontuberculous mycobacteria (SGM) infection, 29 were detected with Mycobacterium avium complex (n = 13, M. avium; n = 16, M. intracellulare), and 4 with M. kansasii. Among 31 (48.4%) patients with rapidly growing nontuberculous mycobacteria (RGM) infection, 27 and 4 patients were detected with M. abscessus complex and M. fortuitum complex, respectively. RGM patients were more likely to have current Tb (P = 0.041), cough (P < 0.05), and sputum (P < 0.01) than SGM patients in the univariate analysis, but not in the multivariate analysis.ConclusionGiven the increasing prevalence of NTM infections, precise epidemiological and surveillance data should be obtained by reporting NTM infections to public health authorities. Introducing nucleic acid amplification tests to differentiate between Tb and NTM in smear-positive specimens should be considered.

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Section: Discussionsupporting

confidence: 87%

Nontuberculosis mycobacterial infections at a specialized tuberculosis treatment centre in the Republic of Korea

Yoon

Choi

2017

BMC Infect Dis

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“…In recent years, the technique has also started to be implemented in mycobacterial laboratories due to substantial improvements in sample preparation and the quality of spectral databases. We confirm in this study that MALDI-TOF MS allows a very reliable distinction between M. tuberculosis and NTM species if score thresholds are lowered from Ն2.0 for routine bacterial identifications to Ն1.8 for mycobacteria (30)(31)(32). Using this cutoff value, 90.4% of the species identifications corresponded to gold-standard methods despite the presence of two MBT-ASTRA standard peaks in the mass spectra.…”

Section: Discussionsupporting

confidence: 74%

“…As it allows pathogen-specific culture and protein extraction protocols (34,35), we first optimized our in-house mycobacterial cell disruption and protein extraction protocol for MALDI-TOF MS analysis. Upon comparison of various described protocols using M. tuberculosis H37Rv cells (22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34), we found that in our hands, bead beating in the presence of 1.2 ml of 70% ethanol gave the best output in terms of peak intensity and identification scores (Table S1).…”

Section: Resultsmentioning

confidence: 90%

“…Unlike most bacteria, mycobacteria require prior inactivation and disruption of the mycolic acid-rich cell wall, both for biosafety reasons and to liberate the cellular protein content. Numerous suitable procedures have been proposed, combining heat-killing, ethanol, sonication, and/or silica-based bead beating preceding the regular formic acid/acetonitrile extraction (21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33). The reported success rates vary between 55% and 98% correct species-level identifications, but the large variety in strain collections, culture conditions, extraction protocols, hardware, and databases hinder data comparison between publications.…”

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confidence: 99%

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Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Combined Species Identification and Drug Sensitivity Testing in Mycobacteria

et al. 2017

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Species identification and drug susceptibility testing (DST) of mycobacteria are important yet complex processes traditionally reserved for reference laboratories. Recent technical improvements in matrix-assisted laser desorption ionizationtime of flight mass spectrometry (MALDI-TOF MS) has started to facilitate routine mycobacterial identifications in clinical laboratories. In this paper, we investigate the possibility of performing phenotypic MALDI-based DST in mycobacteriology using the recently described MALDI Biotyper antibiotic susceptibility test rapid assay (MBT-ASTRA). We randomly selected 72 clinical Mycobacterium tuberculosis and nontuberculous mycobacterial (NTM) strains, subjected them to MBT-ASTRA methodology, and compared its results to current gold-standard methods. Drug susceptibility was tested for rifampin, isoniazid, linezolid, and ethambutol (M. tuberculosis, n ϭ 39), and clarithromycin and rifabutin (NTM, n ϭ 33). Combined species identification was performed using the Biotyper Mycobacteria Library 4.0. Mycobacterium-specific MBT-ASTRA parameters were derived (calculation window, m/z 5,000 to 13,000, area under the curve [AUC] of Ͼ0.015, relative growth [RG] of Ͻ0.5; see the text for details). Using these settings, MBT-ASTRA analyses returned 175/177 M. tuberculosis and 65/66 NTM drug resistance profiles which corresponded to standard testing results. Turnaround times were not significantly different in M. tuberculosis testing, but the MBT-ASTRA method delivered on average a week faster than routine DST in NTM. Databases searches returned 90.4% correct species-level identifications, which increased to 98.6% when score thresholds were lowered to 1.65. In conclusion, the MBT-ASTRA technology holds promise to facilitate and fasten mycobacterial DST and to combine it directly with high-confidence species-level identifications. Given the ease of interpretation, its application in NTM typing might be the first in finding its way to current diagnostic workflows. However, further validations and automation are required before routine implementation can be envisioned.KEYWORDS drug susceptibility testing, MALDI-TOF, MBT-ASTRA, mycobacteria T he genus Mycobacterium comprises at least 175 recognized species (List of Prokaryotic Names with Standing in Nomenclature [LPSN] database) with a wide spectrum of pathogenicity. Mycobacterium tuberculosis, the leading cause of tuberculosis (TB), is among the greatest public health threats in low-income countries. According to the latest WHO report, TB ranks now alongside HIV as a primary cause of death

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“…Discussion MALDI-TOF MS is in use by clinical laboratories for the identification of bacteria as it is successful, rapid, userfriendly, and cost-effective to implement. The profitable outcomes obtained with this technique have attracted researchers' interest in utilizing this technology to identify mycobacterial species (18). In this study, we compared the usefulness of the newly enhanced database for mycobacteria identification with MBT ML4.0.…”

Section: Resultsmentioning

confidence: 99%

Evaluation of the performance of MALDI-TOF MS and DNA sequence analysis in the identification of mycobacteria species

Akyar¹,

Çavuşoğlu²,

Ayas³

et al. 2018

Turk J Med Sci

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Introduction Mycobacterium species constitute an important group of microorganisms that thrive in different natural environments. The taxonomy of Mycobacterium consists of more than 177 species, which have been evolving continuously in the recent past, and some species in the genus are human pathogens. The Mycobacterium tuberculosis complex (MTC) is responsible for tuberculosis infection, which is associated with high morbidity and mortality rates (1). The MTC includes species such as Mycobacterium tuberculosis, Mycobacterium africanum, and Mycobacterium bovis. Other less known species within the MTC are Mycobacterium caprae, Mycobacterium microti, Mycobacterium pinnipedii, Mycobacterium mungi, Mycobacterium suricattae, Mycobacterium orygis, and Mycobacterium canettii (2). By contrast, nontuberculous mycobacteria (NTM) are a group of Mycobacterium species commonly found in the environment, although some NTM species are opportunistic pathogens that can cause critical infectious diseases (3). The mycobacterial species associated with NTM disease are Mycobacterium aviumintracellulare, Mycobacterium chelonae, Mycobacterium fortuitum, Mycobacterium kansasii, Mycobacterium xenopi, Mycobacterium marinum, Mycobacterium scrofulaceum, and Mycobacterium szulgai (1,3-6). Discriminating between MTC and NTM species is crucial for infection control and guidance of antimicrobial therapy and specieslevel identification of clinical NTMs is recommended by the American Thoracic Society (ATS) in order to anticipate the clinical features, permit epidemiological analysis, and guide both infection control strategies and therapeutic options (7,8). Until recently, Mycobacterium species have been identified by traditional methods based on biochemical profiling, morphological characteristics, growth rates, and other phenotypic techniques (5,6). However, Background/aim: Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry is an alternative way of identifying mycobacteria via the analysis of biomolecules. It is being increasingly used in routine microbiology practice since it permits early, rapid, and cost-effective identification of pathogens of clinical importance. In this study, we aimed to evaluate the efficacy of phenotypic identification of mycobacteria by the MALDI-TOF MS MBT Mycobacteria Library (ML) 4.0 (Bruker, Daltonics) compared to standard sequence analysis. Materials and methods: A total of 155 Mycobacterium clinical and external quality control isolates, comprising nontuberculous mycobacteria (NTM) (n = 95) and the Mycobacterium tuberculosis complex (MTC) (n = 60), were included in the study. Results: Identification by MBT ML4.0 was correctly performed in 100% of MTC and in 91% of NTM isolates. All of the MTC isolates were correctly differentiated from NTM isolates. Conclusion: Based on our results, MBT ML4.0 may be used reliably to identify both NTM and MTC.

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Utility of the MALDI-TOF MS method to identify nontuberculous mycobacteria

Cited by 29 publications

References 12 publications

Nontuberculosis mycobacterial infections at a specialized tuberculosis treatment centre in the Republic of Korea

Nontuberculosis mycobacterial infections at a specialized tuberculosis treatment centre in the Republic of Korea

Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Combined Species Identification and Drug Sensitivity Testing in Mycobacteria

Evaluation of the performance of MALDI-TOF MS and DNA sequence analysis in the identification of mycobacteria species

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