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Clinical Microbiology Reviews Apr 2016Molecular typing has revolutionized epidemiological studies of infectious diseases, including those of a mycobacterial etiology. With the advent of fingerprinting... (Review)
Review
Molecular typing has revolutionized epidemiological studies of infectious diseases, including those of a mycobacterial etiology. With the advent of fingerprinting techniques, many traditional concepts regarding transmission, infectivity, or pathogenicity of mycobacterial bacilli have been revisited, and their conventional interpretations have been challenged. Since the mid-1990s, when the first typing methods were introduced, a plethora of other modalities have been proposed. So-called molecular epidemiology has become an essential subdiscipline of modern mycobacteriology. It serves as a resource for understanding the key issues in the epidemiology of tuberculosis and other mycobacterial diseases. Among these issues are disclosing sources of infection, quantifying recent transmission, identifying transmission links, discerning reinfection from relapse, tracking the geographic distribution and clonal expansion of specific strains, and exploring the genetic mechanisms underlying specific phenotypic traits, including virulence, organ tropism, transmissibility, or drug resistance. Since genotyping continues to unravel the biology of mycobacteria, it offers enormous promise in the fight against and prevention of the diseases caused by these pathogens. In this review, molecular typing methods for Mycobacterium tuberculosis and nontuberculous mycobacteria elaborated over the last 2 decades are summarized. The relevance of these methods to the epidemiological investigation, diagnosis, evolution, and control of mycobacterial diseases is discussed.
Topics: Bacterial Typing Techniques; Humans; Molecular Epidemiology; Molecular Typing; Mycobacterium; Mycobacterium Infections; Mycobacterium tuberculosis
PubMed: 26912567
DOI: 10.1128/CMR.00055-15 -
Frontiers in Cellular and Infection... 2021Genome scale mutagenesis identifies many genes required for mycobacterial infectivity and survival, but their contributions and mechanisms of action within the host are...
Genome scale mutagenesis identifies many genes required for mycobacterial infectivity and survival, but their contributions and mechanisms of action within the host are poorly understood. Using CRISPR interference, we created a knockdown of gene in (), which reduced the resistance to acid medium. To further explore the function of PPE31, the mutant strain was generated in and (), respectively. Macrophages infected with the mutant strain caused a reduced inflammatory mediator expressions. In addition, macrophages infected with Δ had decreased host cell death dependent on JNK signaling. Consistent with these results, deletion of from increased the sensitivity to acid medium and reduced cell death in macrophages. Furthermore, we demonstrate that both mutants from and resulted in reduced survival in macrophages, and the survivability of was deceased in zebrafish due to loss of . Our findings confirm that PPE31 as a virulence associated factor that modulates innate immune responses to mycobacterial infection.
Topics: Animals; Cell Death; Mycobacterium Infections, Nontuberculous; Mycobacterium marinum; Mycobacterium tuberculosis; Virulence; Zebrafish
PubMed: 33928042
DOI: 10.3389/fcimb.2021.629836 -
Antimicrobial Agents and Chemotherapy Feb 2021Infections caused by nontuberculous mycobacteria (NTM) are increasing globally. complex (MAC) and complex are the most frequently encountered NTM, and oral treatment...
Infections caused by nontuberculous mycobacteria (NTM) are increasing globally. complex (MAC) and complex are the most frequently encountered NTM, and oral treatment options are extremely limited for these pathogens, especially for the complex. In this study, the potency of omadacycline, a new tetracycline derivative, was tested against 111 isolates of NTM. MIC testing was performed as recommended by the Clinical and Laboratory Standards Institute against 70 isolates of rapidly growing mycobacteria (RGM), of which >90% were tetracycline resistant. These included subsp. (20 isolates), subsp. (3), (15 isolates), (7 isolates), the group, including six doxycycline-resistant isolates (12 isolates), and the group, including four doxycycline-resistant isolates (10 isolates). Forty-one isolates of slowly growing mycobacteria (SGM), including 16 isolates of MAC, were also tested. Omadacycline was active against all RGM species, with MIC ranges of 0.004 to 0.25 and 0.06 to 1 μg/ml for 80% and 100% inhibition, respectively. For subsp. , MICs were 0.06 and 0.12 μg/ml with 80% and 100% inhibition, respectively. There was considerable trailing of the omadacycline endpoint with the RGM. MICs of tigecycline exhibited no trailing and were generally within 1 to 2 dilutions of the 100% inhibition omadacycline MICs. While there was no trailing observed in SGM, omadacycline MICs were higher (MIC range, 8 to >16 μg/ml; = 41), as previously noted with tigecycline. This study supports further research of omadacycline, including clinical trials, for the treatment of RGM infections, especially .
Topics: Anti-Bacterial Agents; Humans; Microbial Sensitivity Tests; Mycobacteriaceae; Mycobacterium Infections, Nontuberculous; Nontuberculous Mycobacteria; Tetracyclines
PubMed: 33288634
DOI: 10.1128/AAC.01947-20 -
Methods in Molecular Biology (Clifton,... 2021Mass spectrometry-based single-cell proteomic analysis has recently gained momentum and is now an emerging area with established protocols and promising results....
Mass spectrometry-based single-cell proteomic analysis has recently gained momentum and is now an emerging area with established protocols and promising results. Traditional proteomic studies, especially involving bacteria, have been limited to suspension cultures with large protein yields. Such studies, however, remain population centered with the uniqueness of individual responses to environmental challenges becoming diluted. To enable bacterial single-colony proteomics, we describe a quantitative mass spectrometry-based protocol to isolate and analyze the proteome of a single mycobacterial colony from 7H10 media, with growth supplements for optimal growth. Following protein purification and digestion, tryptic peptides are analyzed by UHPLC coupled to a hybrid Q Exactive mass spectrometer. Raw data were analyzed using the MaxQuant Suite, and downstream statistical analysis was performed using Perseus software. A total of 7805 unique peptides and 1387 proteins were identified. Data are available via ProteomeXchange with identifier PXD018168. In this chapter, we identify steps most prone to sample loss and describe measures of alleviation that allows the preservation of protein yield and boosts quantitative power while increasing reproducibility, of "very limiting samples."
Topics: Bacterial Proteins; Chromatography, Liquid; Humans; Mycobacterium; Mycobacterium Infections; Mycobacterium smegmatis; Proteome; Proteomics; Tandem Mass Spectrometry
PubMed: 33687715
DOI: 10.1007/978-1-0716-1178-4_11 -
Microbiology Spectrum Apr 2022Pathogenic intracellular mycobacteria, such as Mycobacterium tuberculosis and Mycobacterium avium, which cause lung diseases, can grow in macrophages. Extracellular...
Pathogenic intracellular mycobacteria, such as Mycobacterium tuberculosis and Mycobacterium avium, which cause lung diseases, can grow in macrophages. Extracellular mycobacteria have been reported in the lungs, blood, and sputum of patients, indicating the involvement of these pathogens in disease progression. Erythrocytes are involved in the symptoms associated with pulmonary mycobacterial diseases, such as bloody sputum and hemoptysis; however, little attention has been paid to the role of erythrocytes in mycobacterial diseases. Herein, we found that Mycobacterium avium subsp. (MAH) and Mycobacterium intracellulare colocalized with erythrocytes at the sites of lung infection, inside capillaries and necrotic areas of granulomas, using histopathological examinations. Electron microscopy showed that MAH adhered and entered human erythrocytes when they were cocultured . MAH adhered to erythrocytes through complement receptor 1 and cell-surface sialo-glycoproteins. Importantly, MAH grew vigorously without causing any pronounced damage to erythrocytes. This erythrocyte-mediated enhancement of MAH growth occurred extracellularly depending on its direct attachment to erythrocytes. In contrast, MAH failed to multiply inside erythrocytes. Similarly, erythrocytes augmented the growth of other pathogenic mycobacteria, such as M. intracellulare and M. tuberculosis. THP-1 cell-derived human macrophages preferentially phagocytosed erythrocytes that were attached to mycobacteria (compared to bacteria alone), suggesting that erythrocyte-attached mycobacteria are an efficient infectious source for macrophages. Our findings provide new insights into the pathogenesis of mycobacterial diseases and offer an alternative and useful strategy for treating mycobacterial disease. Pathogenic mycobacteria, such as Mycobacterium tuberculosis, Mycobacterium avium subsp. (MAH), and Mycobacterium intracellulare, cause pulmonary infections as intracellular parasites of lung macrophages and epithelial cells. Here, using histopathological examinations we found that MAH and M. intracellulare colocalized with erythrocytes in lung infection sites. Subsequent studies demonstrated that direct interaction with erythrocytes enhances the extracellular proliferation of mycobacteria based on the following results: 1. MAH adhered and invaded human erythrocytes upon coculture ; 2. MAH adhered to erythrocytes through complement receptor 1 and cell-surface sialo-glycoproteins; 3. MAH rapidly proliferated when directly attached to erythrocytes but not within them; 4. other mycobacteria, such as M. intracellulare and M. tuberculosis, also proliferated in the same way as MAH. The finding that pathogenic mycobacteria grow extracellularly in an erythrocyte-dependent manner is of considerable clinical importance for understanding disease progression and latent infection.
Topics: Disease Progression; Erythrocytes; Glycoproteins; Humans; Mycobacterium; Mycobacterium avium Complex; Mycobacterium avium-intracellulare Infection; Mycobacterium tuberculosis; Receptors, Complement; Tuberculosis
PubMed: 35293805
DOI: 10.1128/spectrum.02454-21 -
Current Medicinal Chemistry 2017The complex architecture of the mycobacterial cell wall is responsible for many physiological and infection-associated properties of these pathogens. Long chain mycolic... (Review)
Review
BACKGROUND
The complex architecture of the mycobacterial cell wall is responsible for many physiological and infection-associated properties of these pathogens. Long chain mycolic acids with chiral functional groups constitute a major lipid envelope component, and therefore play a crucial role in determining the permeability and fluidity of the cell wall. Varying proportions of the different mycolate types are present in various mycobacteria. This serves to designate a specific mycolic acid profile, allowing the differentiation of species and subspecies.
OBJECTIVE
In this review, we explore the diversity in mycolic acid chemical structure, its influence on cell wall permeability and consequences for virulence, and present how they might be exploited as research targets in diagnosis and chemotherapy.
METHODS
The search of bibliographic databases for adequate, informative and valuable peerreviewed literature was undertaken. The proper papers were identified by the hand and electronic searching through the relevant to the topic-leading journals, key words, named authors, reference scanning, etc.
RESULTS
The review is based on the ninety two carefully selected articles that allow this review to provide up-to-date information. Twenty nine papers were published within last 5 years, including 10 showed up in 2016-2017.
CONCLUSION
The revision of the relevant literature showed that mycolic acids played a crucial role in host-pathogen interactions and thus might serve as a promising tool for differentiation of mycobacterial species and discovering novel tuberculocidal therapeutic strategies.
Topics: Cell Membrane Permeability; Host-Pathogen Interactions; Mycobacterium; Mycolic Acids
PubMed: 28831917
DOI: 10.2174/0929867324666170823130445 -
Proteomics. Clinical Applications Apr 2016Identification and typing of bacteria occupy a large fraction of time and work in clinical microbiology laboratories. With the certification of some MS platforms in... (Review)
Review
Identification and typing of bacteria occupy a large fraction of time and work in clinical microbiology laboratories. With the certification of some MS platforms in recent years, more applications and tests of MS-based diagnosis methods for bacteria identification and typing have been created, not only on well-accepted MALDI-TOF-MS-based fingerprint matches, but also on solving the insufficiencies of MALDI-TOF-MS-based platforms and advancing the technology to areas such as targeted MS identification and typing of bacteria, bacterial toxin identification, antibiotics susceptibility/resistance tests, and MS-based diagnostic method development on unique bacteria such as Clostridium and Mycobacteria. This review summarizes the recent development in MS platforms and applications in bacteria identification and typing of common pathogenic bacteria.
Topics: Bacterial Toxins; Bacterial Typing Techniques; Campylobacter jejuni; Clostridium; Escherichia coli; Humans; Listeria monocytogenes; Microbial Sensitivity Tests; Mycobacteriaceae; Peptide Fragments; Proteolysis; Proteomics; Salmonella; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Trypsin
PubMed: 26751976
DOI: 10.1002/prca.201500086 -
Annals of Agricultural and... Mar 2022The complex (MAC) is a group of acid-resistant bacteria within the Mycobacteriaceae. Their cell walls have a specific structure impervious to many disinfectants.... (Review)
Review
INTRODUCTION AND OBJECTIVE
The complex (MAC) is a group of acid-resistant bacteria within the Mycobacteriaceae. Their cell walls have a specific structure impervious to many disinfectants. Mycobacteria are widespread in the environment and can also be found in food. This aim of the article is to review the current state of knowledge about the sources of infection, symptoms and treatment of MAC diseases in humans and animals, and summarizes the available methods for identifying the bacteria. It pays a special attention to the zoonotic potential of MAC bacteria and possible routes of transmission between humans and animals, including possible food-borne routes.
BRIEF DESCRIPTION OF THE STATE OF KNOWLEDGE.
MAC bacterial infections occur both in immunocompetent people and those with functional predispositions and compromised immunity, particularly during HIV infection or immunosuppressive treatment. The incidence of MAC infections in humans is growing, with the most common form of infection being pulmonary disease (MTC-PD); however, there are conflicting reports on the role of paratuberculosis (MAP) in the development of Crohn's disease. MAC bacteria can also attack livestock, household pets, and wild animals. Unfortunately, treatment is lengthy and often fails due to microbiological relapse; there is also increasing evidence of MAC bacteria are developing multi-drug resistance.
CONCLUSIONS
Although new antibiotics are being created to inhibit the growth and division of , there is clearly a need for further research into the virulence factors associated with MAC bacteria. Further studies should also examine the role of MAP in the etiopathogenesis of Crohn's disease.
Topics: Animals; Crohn Disease; HIV Infections; Humans; Mycobacterium avium Complex; Mycobacterium avium subsp. paratuberculosis; Mycobacterium avium-intracellulare Infection
PubMed: 35352901
DOI: 10.26444/aaem/136398 -
Frontiers in Immunology 2023Despite the widespread use of standardised drug regimens, advanced diagnostics, and Bacille-Calmette-Guérin (BCG) vaccines, the global tuberculosis (TB) epidemic... (Review)
Review
Despite the widespread use of standardised drug regimens, advanced diagnostics, and Bacille-Calmette-Guérin (BCG) vaccines, the global tuberculosis (TB) epidemic remains uncontrollable. To address this challenge, improved vaccines are urgently required that can elicit persistent immunologic memory, the hallmark of successful vaccines. Nonetheless, the processes underlying the induction and maintenance of immunologic memory are not entirely understood. Clarifying how memory T cells (Tm cells) are created and survive long term may be a crucial step towards the development of effective T cell-targeted vaccines. Here, we review research findings on the memory T cell response, which involves mobilization of several distinct Tm cell subsets that are required for efficient host suppression of (Mtb) activity. We also summaries current knowledge related to the T cell response-based host barrier against Mtb infection and discuss advantages and disadvantages of novel TB vaccine candidates.
Topics: Humans; Memory T Cells; Tuberculosis; BCG Vaccine; Mycobacterium tuberculosis; Mycobacterium bovis
PubMed: 37063832
DOI: 10.3389/fimmu.2023.1100741 -
Journal of Global Antimicrobial... Sep 2021The incidence of infections due to Mycobacterium avium complex (MAC) and Mycobacterium abscessus (MABS) is increasing worldwide. Current antimycobacterial agents are not... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVES
The incidence of infections due to Mycobacterium avium complex (MAC) and Mycobacterium abscessus (MABS) is increasing worldwide. Current antimycobacterial agents are not sufficiently effective against nontuberculous mycobacteria (NTM) and there is a need for new drugs. This study aimed to estimate the overall in vitro activity of clofazimine (CFZ) against MAC and MABS clinical isolates.
METHODS
We systematically searched four databases up to 1 March 2020 to identify relevant studies. Studies were included if they used the Clinical and Laboratory Standards Institute (CLSI) criteria for drug susceptibility testing (DST). We assessed the pooled in vitro CFZ resistance rate in MAC and MABS clinical isolates using a random- effects model. Sources of heterogeneity were evaluated using Cochran's Q and the I statistic. Potential for publication bias was explored using Begg's and Egger's tests. All analyses were conducted using Stata 14.0.
RESULTS
A total of 20 publications (11 reports for MAC and 15 for MABS) were included. The pooled rates of in vitro resistance to CFZ in clinical isolates of MAC and MABS were 9.0% [95% confidence interval (CI) 3.0-17.0%] and 16.0% (95% CI 4.0-34.0%), respectively. There was no evidence of publication bias.
CONCLUSION
This study reports the frequency of CFZ resistance in clinical isolates of MAC and MABS. According to the results, establishing accurate DST methods for detecting CFZ resistance, performing DST for all NTM isolates to provide effective treatment, and continuous monitoring of drug resistance are suggested for the prevention and control of CFZ-resistant NTM.
Topics: Clofazimine; Humans; Microbial Sensitivity Tests; Mycobacterium abscessus; Mycobacterium avium Complex; Mycobacterium avium-intracellulare Infection; Mycobacterium tuberculosis
PubMed: 34153525
DOI: 10.1016/j.jgar.2021.06.002