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Clinical Microbiology Reviews Jan 2004Environmental mycobacteria are emerging pathogens causing opportunistic infections in humans and animals. The health impacts of human-mycobacterial interactions are... (Review)
Review
Environmental mycobacteria are emerging pathogens causing opportunistic infections in humans and animals. The health impacts of human-mycobacterial interactions are complex and likely much broader than currently recognized. Environmental mycobacteria preferentially survive chlorination in municipal water, using it as a vector to infect humans. Widespread chlorination of water has likely selected more resistant environmental mycobacteria species and potentially explains the shift from M. scrofulaceum to M. avium as a cause of cervical lymphadenitis in children. Thus, human activities have affected mycobacterial ecology. While the slow growth and hydrophobicity of environmental mycobacteria appear to be disadvantages, the unique cell wall architecture also grants high biocide and antibiotic resistance, while hydrophobicity facilitates nutrient acquisition, biofilm formation, and spread by aerosolization. The remarkable stress tolerance of environmental mycobacteria is the major reason they are human pathogens. Environmental mycobacteria invade protozoans, exhibiting parasitic and symbiotic relationships. The molecular mechanisms of mycobacterial intracellular pathogenesis in animals likely evolved from similar mechanisms facilitating survival in protozoans. In addition to outright infection, environmental mycobacteria may also play a role in chronic bowl diseases, allergies, immunity to other pulmonary infections, and the efficacy of bacillus Calmette-Guerin vaccination.
Topics: Animals; Environmental Microbiology; Eukaryota; Humans; Incidence; Mycobacterium Infections, Nontuberculous; Nontuberculous Mycobacteria; Tuberculosis
PubMed: 14726457
DOI: 10.1128/CMR.17.1.98-106.2004 -
The European Respiratory Journal Apr 1998We describe the case of a patient with a chronic pulmonary infection due to a mycobacterium tentatively identified as Mycobacterium flavescens, but finally shown to be... (Review)
Review
We describe the case of a patient with a chronic pulmonary infection due to a mycobacterium tentatively identified as Mycobacterium flavescens, but finally shown to be Mycobacterium szulgai; this is the first M. szulgai infection reported in Italy. The patient responded to treatment with multiple antituberculosis drugs only after two cycles of 10 and 6 months, respectively. The literature concerning previous case reports in which M. szulgai is involved is revised and the difficulty concerning the identification of this rare mycobacterium, along with its in vitro and in vivo susceptibility, are discussed.
Topics: Humans; Male; Middle Aged; Mycobacterium Infections, Nontuberculous; Nontuberculous Mycobacteria; Tuberculosis, Pulmonary
PubMed: 9623706
DOI: 10.1183/09031936.98.11040975 -
Experimental and Clinical... Oct 2021Data are limited regarding the clinical significance of nontuberculous mycobacteria pulmonary infections among lung transplant recipients. We investigated the incidence...
OBJECTIVES
Data are limited regarding the clinical significance of nontuberculous mycobacteria pulmonary infections among lung transplant recipients. We investigated the incidence and characteristics of pulmonary nontuberculous mycobacteria infection in ourlung transplant patient population.
MATERIALS AND METHODS
We obtaineddata of the patients who underwent lung transplant in our center from January 1997 to March 2019.
RESULTS
Of 690 patients, nontuberculous mycobacteria were identified in 58 patients (8.4%) over a median follow-up of 3 years. Types of species were as follows: Mycobacterium simiae (n = 24), avium complex (n = 12), abscessus (n = 9), fortuitum (n = 6), chelonae (n = 2), szulgai (n = 1), kansasii (n = 1), lentiflavum (n = 1), and undefined mycobacteria (n = 2). When we compared infections in the early versus late period posttransplant (before and after 6 months), infections with Mycobacterium simiae (16 vs 8 incidents) and Mycobacterium fortuitum (5 vs 1 incident) were more often observed within the early period, whereas most Mycobacterium abscessus (7 vs 1 incident) and Mycobacterium avium complex (9 vs 3 incidents) were observed in the later period. The median forced expiratory volume in 1 second overtime did not differ significantly between patients with and without nontuberculous mycobacteria infection (P = .29). Nontuberculous mycobacteria acquisition was significantly associated with decreased survival (relative risk of 2.41, 95% CI, 1.70-3.43; P ⟨ .001).
CONCLUSIONS
The nontuberculous mycobacteria species isolated varied according to the time elapsed since transplant. Among lung transplant recipients, nontuberculous mycobacteria infection was associated with increased mortality but not with lung dysfunction.
Topics: Humans; Lung; Mycobacterium; Mycobacterium Infections, Nontuberculous; Nontuberculous Mycobacteria; Opportunistic Infections; Transplant Recipients; Treatment Outcome
PubMed: 34641777
DOI: 10.6002/ect.2021.0177 -
International Journal of... Jun 2015Pulmonary infections with nontuberculous mycobacteria (NTM) are recognized as a problem in immunodeficient individuals and are increasingly common in older people with... (Review)
Review
Pulmonary infections with nontuberculous mycobacteria (NTM) are recognized as a problem in immunodeficient individuals and are increasingly common in older people with no known immune defects. NTM are found in soil and water, but factors influencing transmission from the environment to humans are mostly unknown. Studies of the epidemiology of NTM disease have matched some clinical isolates of NTM with isolates from the patient's local environment. Definitive matching requires strain level differentiation based on molecular analyses, including partial sequencing, PCR-restriction fragment length polymorphism (RFLP) analysis, random amplified polymorphic DNA (RAPD) PCR, repetitive element (rep-) PCR and pulsed field gel electrophoresis (PFGE) of large restriction fragments. These approaches have identified hospital and residential showers and faucets, hot-tubs and garden soil as sources of transmissible pathogenic NTM. However, gaps exist in the literature, with many clinical isolates remaining unidentified within environments that have been tested, and few studies investigating NTM transmission in developing countries. To understand the environmental reservoirs and transmission routes of pathogenic NTM, different environments, countries and climates must be investigated.
Topics: Environmental Microbiology; Humans; Mycobacterium Infections, Nontuberculous; Nontuberculous Mycobacteria
PubMed: 26972876
DOI: 10.1016/j.ijmyco.2015.03.002 -
Journal of the Formosan Medical... Jun 2020Great progress has recently been made in methodologies for identifying nontuberculous mycobacteria (NTM). Recommendations for drug susceptibility testing (DST) of NTM... (Review)
Review
Great progress has recently been made in methodologies for identifying nontuberculous mycobacteria (NTM). Recommendations for drug susceptibility testing (DST) of NTM have been expanded and updated by the Clinical and Laboratory Standards Institute and are crucial in the management of NTM infections. This article summarizes the clinically relevant molecular methods used to discriminate NTM species and updates the information on DST. Furthermore, recent progress on new antimicrobials against NTM infections is reviewed.
Topics: Anti-Bacterial Agents; Humans; Microbial Sensitivity Tests; Mycobacterium Infections, Nontuberculous; Mycobacterium tuberculosis; Nontuberculous Mycobacteria
PubMed: 32423573
DOI: 10.1016/j.jfma.2020.05.002 -
BMC Infectious Diseases Mar 2024Nontuberculous mycobacteria (NTM) are environmental bacteria which may cause chronic lung disease. The prevalence of NTM pulmonary infection and disease has been...
BACKGROUND
Nontuberculous mycobacteria (NTM) are environmental bacteria which may cause chronic lung disease. The prevalence of NTM pulmonary infection and disease has been increasing in the United States and globally. The predominant clinically relevant species of NTM in the United States are Mycobacterium avium complex (MAC) species and Mycobacterium abscessus. With the development of rapid species identification methods for NTM (e.g. PCR probes), more testing for NTM is being conducted through commercial labs, such as Laboratory Corporation of America (Labcorp), which provides deidentified real-time testing data to the Centers for Disease Control (CDC) pursuant to a data sharing agreement. Because NTM lung infections are not reportable in most states, other data sources are key to understanding NTM testing patterns, positivity rates, and species distributions to track infection trends and identify clinical care needs.
METHODS
We obtained national Labcorp data for the period January 2019 through mid-April 2022. We subset the data to only respiratory samples sent for Acid Fast Bacilli (AFB) cultures. NTM positive results were defined as those which identified an NTM species and are not Mycobacterium tuberculosis, Mycobacterium bovis, or Mycobacterium gordonae.
RESULTS
Overall, 112,528 respiratory samples were sent for AFB testing during the study period; 26.3% were from the Southeast U.S., identified as HSS Region IV in the Labcorp dataset, and 23.0% were from the Pacific and South Pacific region (Region IX). The culture positive prevalence ranged from 20.2% in the Southeast to 9.2% in the East North Central region (Region V). In the Southeast US, M. abscessus prevalence was 4.0%. For MAC, the highest prevalence was observed in the Mountain region (Region VII) (13.5%) and the lowest proportion was in the East South Central region (7.3%, Region III). Among positive tests, the proportion which was MAC varied from 61.8% to 88.9% and was highest in the Northeast U.S. The proportion of positive samples which were M. abscessus ranged from 3.8% to 19.7% and was highest in the Southeast.
CONCLUSIONS
The Southeastern region of the U.S. has the highest rate of culture positivity in Labcorp tests for total NTM and, of all positive tests, the highest proportion of M. abscessus. These estimates may underrepresent the true number of M. abscessus infections because M. absesscus-specific probes are not commercially available and not all NTM testing in the United States is done by Labcorp. Analysis of real-time testing data from commercial laboratories may provide insights into risk factors for NTM culture positivity in 'hotspot' areas.
Topics: United States; Humans; Nontuberculous Mycobacteria; Mycobacterium avium Complex; Mycobacterium abscessus; Laboratories; Mycobacterium bovis; Opportunistic Infections
PubMed: 38448840
DOI: 10.1186/s12879-024-09059-9 -
Infection Control and Hospital... Jul 2017OBJECTIVE Activated alkaline glutaraldehyde (GTA) remains one of the most widely used high-level disinfectants worldwide. However, several reports have highlighted the...
OBJECTIVE Activated alkaline glutaraldehyde (GTA) remains one of the most widely used high-level disinfectants worldwide. However, several reports have highlighted the potential for nontuberculous mycobacteria to develop high-level resistance to this product. Because aldehyde resistance may lead to cross-resistance to other biocides, we investigated the susceptibility profile of GTA-resistant Mycobacterium chelonae and M. abscessus isolates to various disinfectant chemistries. METHODS High-level disinfectants commonly used in the reprocessing of endoscopes and other heat-sensitive, semicritical medical equipment, including different formulations of aldehyde-based products and oxidizing agents, were tested against 10 slow- and fast-growing, GTA-susceptible and GTA-resistant, Mycobacterium isolates in suspension tests and carrier tests at different temperatures. RESULTS While peracetic acid- and hydrogen peroxide-based disinfectants (S40, Resert XL, Reliance DG) efficiently killed all of the Mycobacterium isolates, GTA- and ortho-phthalaldehyde-based products (ie, Cidex, Aldahol, Cidex OPA) showed variable efficacy against GTA-resistant strains despite the ability of some formulations (Aldahol) to overcome the resistance of some of these isolates, especially when the temperature was increased from 20°C to 25°C. CONCLUSIONS Application permitting, oxidizing chemistries may provide a safe alternative to aldehyde-based products, particularly in GTA-resistant mycobacterial outbreaks. Infect Control Hosp Epidemiol 2017;38:784-791.
Topics: Aldehydes; Disinfectants; Drug Resistance, Bacterial; Glutaral; Microbial Sensitivity Tests; Mycobacterium abscessus; Mycobacterium chelonae; Nontuberculous Mycobacteria; Peracetic Acid; Temperature
PubMed: 28462746
DOI: 10.1017/ice.2017.75 -
Journal of Infection in Developing... Dec 2019Non-tuberculous mycobacterium (NTM) can colonize the human body, leading to opportunistic infection. This study was conducted to analyze the NTM species composition in a...
INTRODUCTION
Non-tuberculous mycobacterium (NTM) can colonize the human body, leading to opportunistic infection. This study was conducted to analyze the NTM species composition in a primary hospital and investigate the potential features of the patients with different NTM species.
METHODOLOGY
Mycobacterial strains were collected from the patients admitted at the hospital from January 2016 to May 2019. MPB64 assay was used to screen NTM strains and confirmed by Rv0577 amplification. The species were identified by hsp65 sequencing. The clinical records of patients with NTM were retrospectively reviewed.
RESULTS
Among the 122 identified NTM isolates, the most common strains were Mycobacterium avium complex (MAC, n = 102, 83.6%), Mycobacterium abscessus (n = 9, 7.4%) and Mycobacterium lentiflavum (n = 5, 4.1%). The predominant species among MAC were Mycobacterium chimaera (n = 57, 46.7%), followed by Mycobacterium intracellulare (n = 25, 20.5%) and Mycobacterium colombiense (n = 17, 13.9%). A significantly lower percentage of positive acid-fast assay was observed in Mycobacterium colombiense positive patients than in those with Mycobacterium intracellulare and Mycobacterium chimaera. Mycobacterium intracellulare was more frequently isolated in patients from the infectious department than in other MAC members.
CONCLUSIONS
A predominant prevalence of Mycobacterium chimaera in Dongyang of Zhejiang Province was different from other regions in China, indicating that its prevalence has been likely underestimated. The heterogeneity in clinical features, caused by different MAC members, required an accurate species identification of the NTM isolated in the primary hospitals.
Topics: Aged; Aged, 80 and over; China; Cross Infection; Female; Humans; Male; Middle Aged; Molecular Epidemiology; Mycobacterium Infections, Nontuberculous; Mycobacterium avium Complex; Mycobacterium avium-intracellulare Infection; Nontuberculous Mycobacteria; Opportunistic Infections; Retrospective Studies; Species Specificity
PubMed: 32088696
DOI: 10.3855/jidc.11772 -
Tuberculosis (Edinburgh, Scotland) Mar 2019All mycobacteria, including nontuberculous mycobacteria (NTM), synthesize an array of lipids including phosphatidylinositol mannosides (PIM), lipomannan (LM), and... (Review)
Review
All mycobacteria, including nontuberculous mycobacteria (NTM), synthesize an array of lipids including phosphatidylinositol mannosides (PIM), lipomannan (LM), and lipoarabinomannan (LAM). While absent from Mycobacterium tuberculosis (M. tb), glycopeptidolipids (GPL) are critical to the biology of NTM. M. tb and some NTM also synthesize trehalose-containing glycolipids and phenolic glycolipids (PGL), key membrane constituents with essential roles in metabolism. While lipids facilitate immune evasion, they also induce host immunity against tuberculosis. However, much less is known about the significance of NTM-derived PIM, LM, LAM, GPL, trehalose-containing glycolipids, and PGL as virulence factors, warranting further investigation. While culling the scientific literature on NTM lipids, it's evident that such studies were relatively few in number with the overwhelming majority of prior work dedicated to understanding lipids from the saprophyte Mycobacterium smegmatis. The identification and functional analysis of immune reactive NTM-derived lipids remain challenging, but such work is likely to yield a greater understanding of the pathogenesis of NTM lung disease. In this review, we juxtapose the vast literature of what is currently known regarding M. tb lipids to the lesser number of studies for comparable NTM lipids. But because GPL is the most widely recognized NTM lipid, we highlight its role in disease pathogenesis.
Topics: Bacillus; Cell Wall; Immunity, Cellular; Lipids; Mycobacterium tuberculosis; Nontuberculous Mycobacteria
PubMed: 30948183
DOI: 10.1016/j.tube.2019.02.008 -
Microbiology Spectrum Jun 2024Four species of non-tuberculous mycobacteria (NTM) rated as biosafety level 1 or 2 (BSL-1/BSL-2) organisms and showing higher genomic similarity with () than previous...
Four species of non-tuberculous mycobacteria (NTM) rated as biosafety level 1 or 2 (BSL-1/BSL-2) organisms and showing higher genomic similarity with () than previous comparator species and were subjected to genomic and phenotypic characterization. These species named , , and might represent "missing links" between low-virulent mycobacterial opportunists and the highly virulent obligate pathogen . We confirmed that is the closest NTM species to currently known and found that it has an optimal growth temperature of 32°C-35°C and not 37°C. showed resistance to rifampicin, isoniazid, and ethambutol, whereas and showed resistance to isoniazid and ethambutol. was sensitive to all three first-line TB drugs, and all four species were sensitive to bedaquiline, a third-generation anti-TB drug. Our results suggest these four NTM may be useful models for the identification and study of new anti-TB molecules, facilitated by their culture under non-BSL-3 conditions as compared to was the most virulent of the four species in cellular and mouse infection models. also multiplied in THP-1 cells at 35°C but was growth impaired at 37°C. Genomic comparisons showed that the locus, essential for the secretion of ESX-1 proteins in , was present only in , which was able to secrete ESAT-6 and CFP-10, whereas secretion of these antigens varied in the other species, making the four species interesting examples for studying ESX-1 secretion mechanisms.IMPORTANCEIn this work, we investigated recently identified opportunistic mycobacterial pathogens that are genomically more closely related to () than previously used comparator species and . We confirmed that is the currently closest known species to the tubercle bacilli, represented by and strains. Surprisingly, the reference strain of (DSM 45176), which was purchased as a biosafety level 1 (BSL-1)-rated organism, was the most virulent of the four species in the tested cellular and mouse infection models, suggesting that a BSL-2 rating might be more appropriate for this strain than the current BSL-1 rating. Our work establishes the four NTM species as interesting study models to obtain new insights into the evolutionary mechanisms and phenotypic particularities of mycobacterial pathogens that likely have also impacted the evolution of the key pathogen .
Topics: Mycobacterium tuberculosis; Antitubercular Agents; Nontuberculous Mycobacteria; Humans; Genome, Bacterial; Genomics; Phenotype; Microbial Sensitivity Tests; Mycobacterium Infections, Nontuberculous; Phylogeny; Animals; Tuberculosis; Drug Resistance, Bacterial; Mice
PubMed: 38700329
DOI: 10.1128/spectrum.04126-23