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International Journal of... Mar 2015Nontuberculous mycobacteria (NTM) are emergent pathogens whose importance in human health has been gaining relevance after being recognized as etiological agents of...
Nontuberculous mycobacteria (NTM) are emergent pathogens whose importance in human health has been gaining relevance after being recognized as etiological agents of opportunist infections in HIV patients. Currently, NTM are recognized as etiological agents of several respiratory and extra-respiratory infections of immune-competent individuals. The environmental nature of NTM together with the ability to assemble biofilms on different surfaces plays a key role on their pathogenesis. In the present work the ability of three fast-growing NTM (Mycobacterium smegmatis, Mycobacterium fortuitum and Mycobacterium chelonae) to persist within a model of human alveolar macrophages was evaluated. Most often human infections with NTM occur by contact with the environment. Biofilms can work as environmental reservoirs. For this reason, it was decided to evaluate the ability of NTM to assemble biofilms on different surfaces. Scanning electron microscopy was used to elucidate the biofilm structure. The ability to assemble biofilms was connected with the ability to spread on solid media known as sliding. Biofilm assembly and intracellular persistence seems to be ruled by different mechanisms.
Topics: Bacterial Adhesion; Biofilms; Cell Line; Humans; Macrophages, Alveolar; Microscopy, Electron, Scanning; Mycobacterium Infections, Nontuberculous; Mycobacterium chelonae; Mycobacterium fortuitum; Mycobacterium smegmatis; Nontuberculous Mycobacteria
PubMed: 26655196
DOI: 10.1016/j.ijmyco.2014.11.065 -
Journal of Clinical Microbiology Nov 2012Successful long-term preservation of Mycobacterium tuberculosis cells is important for sample transport, research, biobanking, and the development of new drugs,...
Successful long-term preservation of Mycobacterium tuberculosis cells is important for sample transport, research, biobanking, and the development of new drugs, vaccines, biomarkers, and diagnostics. In this report, Mycobacterium bovis bacillus Calmette-Guérin and M. tuberculosis H37Ra were used as models of M. tuberculosis complex strains to study cryopreservation of M. tuberculosis complex cells in diverse sample matrices at different cooling rates. Cells were cryopreserved in diverse sample matrices, namely, phosphate-buffered saline (PBS), Middlebrook 7H9 medium with or without added glycerol, and human sputum. The efficacy of cryopreservation was quantified by microbiological culture and microscopy with BacLight LIVE/DEAD staining. In all sample matrices examined, the microbiological culture results showed that the cooling rate was the most critical factor influencing cell viability. Slow cooling (a few degrees Celsius per minute) resulted in much higher M. tuberculosis complex recovery rates than rapid cooling (direct immersion in liquid nitrogen) (P < 0.05). Among the three defined cryopreservation media (PBS, 7H9, and 7H9 plus glycerol), there was no significant differential effect on viability (P = 0.06 to 0.87). Preincubation of thawed M. tuberculosis complex cells in 7H9 broth for 20 h before culture on solid Middlebrook 7H10 plates did not help the recovery of the cells from cryoinjury (P = 0.14 to 0.71). The BacLight LIVE/DEAD staining kit, based on Syto 9 and propidium iodide (PI), was also applied to assess cell envelope integrity after cryopreservation. Using the kit, similar percentages of "live" cells with intact envelopes were observed for samples cryopreserved under different conditions, which was inconsistent with the microbiological culture results. This implies that suboptimal cryopreservation might not cause severe damage to the cell wall and/or membrane but instead cause intracellular injury, which leads to the loss of cell viability.
Topics: Colony Count, Microbial; Cryopreservation; Culture Media; Microbial Viability; Microscopy; Mycobacterium bovis; Mycobacterium tuberculosis; Staining and Labeling
PubMed: 22933596
DOI: 10.1128/JCM.00896-12 -
Clinical Microbiology Reviews Jan 1992This paper reviews recent information on the systematics and clinical significance of potentially pathogenic environmental mycobacteria. A short history of these... (Review)
Review
This paper reviews recent information on the systematics and clinical significance of potentially pathogenic environmental mycobacteria. A short history of these mycobacteria is given. Information on species for which clinical and systematic aspects have already been well documented, i.e., Mycobacterium kansasii, M. marinum, M. scrofulaceum, M. simiae, M. szulgai, M. ulcerans, M. xenopi, and members of the M. fortuitum complex, is updated. Although the M. avium complex was extensively reviewed in earlier literature, major new systematic and clinical information is presented in some detail. Species that have received very limited prior coverage, i.e., M. asiaticum, M. haemophilum, M. malmoense, and M. shimoidei, are the main subjects of this review and are discussed in detail. The rare infections attributed to species that are normally considered nonpathogenic, i.e., M. gastri, M. gordonae, the M. terrae complex, and most of the rapidly growing mycobacteria outside of the M. fortuitum complex, are critically reviewed. Finally, suggestions are offered for practical measures that can minimize the risk of failing to isolate or misidentifying some of the more obscure potentially pathogenic environmental mycobacteria that are only infrequently recognized.
Topics: Adult; Female; Humans; Male; Middle Aged; Mycobacterium; Mycobacterium Infections
PubMed: 1735092
DOI: 10.1128/CMR.5.1.1 -
International Journal of... 2023The nutrient medium effects on the quality of the matrix-assisted laser desorption/ionization-time-of-flight (MALDI-ToF) mass spectra. The standard library includes...
Comparison of protein profiles obtained by matrix-assisted laser desorption/ionization-Time-of-flight mass spectrometry in representatives of the family grown on various nutrient media.
BACKGROUND
The nutrient medium effects on the quality of the matrix-assisted laser desorption/ionization-time-of-flight (MALDI-ToF) mass spectra. The standard library includes spectra of microorganisms of the family Mycobacteriaceae grown on the Lowenstein-Jensen and Middlebrook Media. There are new methods for culturing microorganisms from this group, including inoculation on chromogenic media.
METHODS
The study included 240 strains of NTM isolated from patients during tuberculosis examination. The inoculation of the biological material was carried out on solid culture media of Lowenstein-Jensen and universal chromogenic media. Identification of bacteria from both types of media was performed by MALDI-ToF mass spectrometry (Bruker Daltonik GmbH, Germany). Analysis of protein spectra was performed.
RESULTS
For all strains, the spectra revealed both coinciding peaks (regardless of the cultivation medium) and significant differences, including the complete absence of some peaks depending on the medium. The results of a greater divergence of peaks in mass and intensity were obtained for slow-growing species than for fast-growing species. For all analyzed cultures, the number of peaks in the mass spectra was significantly higher when cultivating on a universal chromogenic medium than on a Lowenstein-Jensen medium.
CONCLUSIONS
The use for NTM cultivation of a universal chromogenic medium makes it possible to obtain acceptable identification results by MALDI-ToF mass spectrometry using a standard library.
Topics: Humans; Culture Media; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Mycobacteriaceae; Nutrients; Lasers
PubMed: 37721237
DOI: 10.4103/ijmy.ijmy_137_23 -
Frontiers in Cellular and Infection... 2024The accurate identification of the tuberculosis complex (MTBC) and different nontuberculous mycobacteria (NTM) species is crucial for the timely diagnosis of NTM...
BACKGROUND
The accurate identification of the tuberculosis complex (MTBC) and different nontuberculous mycobacteria (NTM) species is crucial for the timely diagnosis of NTM infections and for reducing poor prognoses. Nucleotide matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) has been extensively used for microbial identification with high accuracy and throughput. However, its efficacy for species identification has been less studied. The objective of this study was to evaluate the performance of nucleotide MALDI-TOF-MS for species identification.
METHODS
A total of 933 clinical isolates were preliminarily identified as NTM by the MPB64 test. These isolates were identified by nucleotide MALDI-TOF-MS and Sanger sequencing. The performance of nucleotide MALDI-TOF MS for identifying various species was analyzed based on Sanger sequencing as the gold standard.
RESULTS
The total correct detection rate of all 933 clinical isolates using nucleotide MALDI-TOF-MS was 91.64% (855/933), and mixed infections were detected in 18.65% (174/933) of the samples. The correct detection rates for , , , , MTBC, , and were 99.32% (585/589), 100% (86/86), 98.46% (64/65), 94.59% (35/37), 100.00% (34/34), 95.65% (22/23), and 100% (19/19), respectively. For the identification of the MTBC, , , , , , and , nucleotide MALDI-TOF-MS and Sanger sequencing results were in good agreement ( > 0.7).
CONCLUSION
In conclusion, nucleotide MALDI-TOF-MS is a promising approach for identifying MTBC and the most common clinical NTM species.
Topics: Humans; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Mycobacterium; Nontuberculous Mycobacteria; Mycobacterium Infections, Nontuberculous; Mycobacterium avium; Mycobacterium abscessus
PubMed: 38379773
DOI: 10.3389/fcimb.2024.1335104 -
BMC Infectious Diseases Nov 2020Mycobacterium houstonense is rapidly growing mycobacteria (RGM) that belongs to M. fortuitum group. So far, there have been few associated reports of human diseases...
BACKGROUND
Mycobacterium houstonense is rapidly growing mycobacteria (RGM) that belongs to M. fortuitum group. So far, there have been few associated reports of human diseases induced by M. houstonense worldwide.
CASE PRESENTATION
We present a delayed-onset postoperative endophthalmitis caused by M. houstonense after glaucoma drainage implant (GDI) surgery. The ocular infection lasted for 2 months without appropriate treatment that developed into endophthalmitis and the patient underwent an emergency enucleation.
CONCLUSION
Implant erosion and a delay in diagnosis of ocular infection could lead to irreversible damage as observed in our case. Ophthalmologists should be alert for ocular RGM infection, and prompt laboratory diagnosis with initiation of effective multidrug therapy might prevent loss of vision.
Topics: Amikacin; Anti-Bacterial Agents; Drug Therapy, Combination; Endophthalmitis; Eye Enucleation; Follow-Up Studies; Glaucoma Drainage Implants; Humans; Levofloxacin; Male; Middle Aged; Mycobacteriaceae; Postoperative Complications; RNA, Ribosomal, 16S; RNA, Ribosomal, 23S; Treatment Outcome
PubMed: 33198648
DOI: 10.1186/s12879-020-05590-7 -
Dalton Transactions (Cambridge, England... Dec 2020Two mononuclear iron(ii)-thiolate complexes have been prepared that represent structural models of the nonheme iron enzymes EgtB and OvoA, which catalyze the...
Two mononuclear iron(ii)-thiolate complexes have been prepared that represent structural models of the nonheme iron enzymes EgtB and OvoA, which catalyze the O2-dependent formation of carbon-sulfur bonds in the biosynthesis of thiohistidine compounds. The series of Fe(ii) complexes reported here feature tripodal N4 chelates (LA and LB) that contain both pyridyl and imidazolyl donors (LA = (1H-imidazol-4-yl)-N,N-bis((pyridin-2-yl)methyl)methanamine; LB = N,N-bis((1-methylimidazol-2-yl)methyl)-2-pyridylmethylamine). Further coordination with monodentate aromatic or aliphatic thiolate ligands yielded the five-coordinate, high-spin Fe(ii) complexes [FeII(LA)(SMes)]BPh4 (1) and [FeII(LB)(SCy)]BPh4 (2), where SMes = 2,4,6-trimethylthiophenolate and SCy = cyclohexanethiolate. X-ray crystal structures revealed that 1 and 2 possess trigonal bipyramidal geometries formed by the N4S ligand set. In each case, the thiolate ligand is positioned cis to an imidazole donor, replicating the arrangement of Cys- and His-based substrates in the active site of EgtB. The geometric and electronic structures of 1 and 2 were analyzed with UV-vis absorption and Mössbauer spectroscopies in tandem with density functional theory (DFT) calculations. Exposure of 1 and 2 to nitric oxide (NO) yielded six-coordinate FeNO adducts that were characterized with infrared and electron paramagnetic resonance (EPR) spectroscopies, confirming that these complexes are capable of binding diatomic molecules. Reaction of 1 and 2 with O2 causes oxidation of the thiolate ligands to disulfide products. The implications of these results for the development of functional models of EgtB and OvoA are discussed.
Topics: Catalytic Domain; Crystallography, X-Ray; Density Functional Theory; Ferrous Compounds; Models, Molecular; Molecular Structure; Mycobacteriaceae; Nonheme Iron Proteins; Oxidoreductases; Sulfhydryl Compounds
PubMed: 33241840
DOI: 10.1039/d0dt03403g -
Antimicrobial Agents and Chemotherapy Dec 2022The FF-ATP synthase is required for the viability of tuberculosis (TB) and nontuberculous mycobacteria (NTM) and has been validated as a drug target. Here, we present...
Structural Elements Involved in ATP Hydrolysis Inhibition and ATP Synthesis of Tuberculosis and Nontuberculous Mycobacterial F-ATP Synthase Decipher New Targets for Inhibitors.
The FF-ATP synthase is required for the viability of tuberculosis (TB) and nontuberculous mycobacteria (NTM) and has been validated as a drug target. Here, we present the cryo-EM structures of the Mycobacterium smegmatis F-ATPase and the FF-ATP synthase with different nucleotide occupation within the catalytic sites and visualize critical elements for latent ATP hydrolysis and efficient ATP synthesis. Mutational studies reveal that the extended C-terminal domain (αCTD) of subunit α is the main element for the self-inhibition mechanism of ATP hydrolysis for TB and NTM bacteria. Rotational studies indicate that the transition between the inhibition state by the αCTD and the active state is a rapid process. We demonstrate that the unique mycobacterial γ-loop and subunit δ are critical elements required for ATP formation. The data underline that these mycobacterium-specific elements of α, γ, and δ are attractive targets, providing a platform for the discovery of species-specific inhibitors.
Topics: Humans; Nontuberculous Mycobacteria; Hydrolysis; Tuberculosis; Mycobacterium; Adenosine Triphosphate; Mycobacterium tuberculosis
PubMed: 36445139
DOI: 10.1128/aac.01056-22 -
BMJ Case Reports Oct 2021is a member of the complex (MTC) that is implicated in bone and joint infections, among others. This group of environmental pathogens can be found in soil, reclaimed...
is a member of the complex (MTC) that is implicated in bone and joint infections, among others. This group of environmental pathogens can be found in soil, reclaimed and drinking water systems, rodents, fish tanks and bioaerosols in duck houses. Interestingly, while is genotypically closely related to the other agents in the MTC, antibiotic susceptibility of these mycobacteria can vary widely and empiric antibiotic therapy is controversial. Our case report contributes to the very limited literature on tenosynovitis-as only six cases have been reported since 2008-and sheds light on different courses of treatment. While previous cases have been successfully treated, a streamlined course of therapy for tenosynovitis is still needed.
Topics: Humans; Mycobacteriaceae; Mycobacterium Infections, Nontuberculous; Nontuberculous Mycobacteria; Tenosynovitis
PubMed: 34667040
DOI: 10.1136/bcr-2021-245130 -
BMC Evolutionary Biology Mar 2016The genome of Mycobacterium tuberculosis contains five copies of the ESX gene cluster, each encoding a dedicated protein secretion system. These ESX secretion systems...
BACKGROUND
The genome of Mycobacterium tuberculosis contains five copies of the ESX gene cluster, each encoding a dedicated protein secretion system. These ESX secretion systems have been defined as a novel Type VII secretion machinery, responsible for the secretion of proteins across the characteristic outer mycomembrane of the mycobacteria. Some of these secretion systems are involved in virulence and survival in M. tuberculosis; however they are also present in other non-pathogenic mycobacteria, and have been identified in some non-mycobacterial actinomycetes. Three components of the ESX gene cluster have also been found clustered in some gram positive monoderm organisms and are predicted to have preceded the ESX gene cluster.
RESULTS
This study used in silico and phylogenetic analyses to describe the evolution of the ESX gene cluster from the WXG-FtsK cluster of monoderm bacteria to the five ESX clusters present in M. tuberculosis and other slow-growing mycobacteria. The ancestral gene cluster, ESX-4, was identified in several nonmycomembrane producing actinobacteria as well as the mycomembrane-containing Corynebacteriales in which the ESX cluster began to evolve and diversify. A novel ESX gene cluster, ESX-4EVOL, was identified in some non-mycobacterial actinomycetes and M. abscessus subsp. bolletii. ESX-4EVOL contains all of the conserved components of the ESX gene cluster and appears to be a precursor of the mycobacterial ESX duplications. Between two and seven ESX gene clusters were identified in each mycobacterial species, with ESX-2 and ESX-5 specifically associated with the slow growers. The order of ESX duplication in the mycobacteria is redefined as ESX-4, ESX-3, ESX-1 and then ESX-2 and ESX-5. Plasmid-encoded precursor ESX gene clusters were identified for each of the genomic ESX-3, -1, -2 and -5 gene clusters, suggesting a novel plasmid-mediated mechanism of ESX duplication and evolution.
CONCLUSIONS
The influence of the various ESX gene clusters on vital biological and virulence-related functions has clearly influenced the diversification and success of the various mycobacterial species, and their evolution from the non-pathogenic fast-growing saprophytic to the slow-growing pathogenic organisms.
Topics: Bacteria; Bacterial Proteins; Multigene Family; Mycobacterium; Mycobacterium tuberculosis; Phylogeny; Plasmids; Protein Transport; Type VII Secretion Systems
PubMed: 26979252
DOI: 10.1186/s12862-016-0631-2