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Immunological Reviews May 2021Upon infection, mycobacteria, such as Mycobacterium tuberculosis (Mtb) and nontuberculous mycobacteria (NTM), are recognized by host innate immune cells, triggering a... (Review)
Review
Upon infection, mycobacteria, such as Mycobacterium tuberculosis (Mtb) and nontuberculous mycobacteria (NTM), are recognized by host innate immune cells, triggering a series of intracellular processes that promote mycobacterial killing. Mycobacteria, however, have developed multiple counter-strategies to persist and survive inside host cells. By manipulating host effector mechanisms, including phagosome maturation, vacuolar escape, autophagy, antigen presentation, and metabolic pathways, pathogenic mycobacteria are able to establish long-lasting infection. Counteracting these mycobacteria-induced host modifying mechanisms can be accomplished by host-directed therapeutic (HDT) strategies. HDTs offer several major advantages compared to conventional antibiotics: (a) HDTs can be effective against both drug-resistant and drug-susceptible bacteria, as well as potentially dormant mycobacteria; (b) HDTs are less likely to induce bacterial drug resistance; and (c) HDTs could synergize with, or shorten antibiotic treatment by targeting different pathways. In this review, we will explore host-pathogen interactions that have been identified for Mtb for which potential HDTs impacting both innate and adaptive immunity are available, and outline those worthy of future research. We will also discuss possibilities to target NTM infection by HDT, although current knowledge regarding host-pathogen interactions for NTM is limited compared to Mtb. Finally, we speculate that combinatorial HDT strategies can potentially synergize to achieve optimal mycobacterial host immune control.
Topics: Anti-Bacterial Agents; Autophagy; Host-Pathogen Interactions; Mycobacterium tuberculosis; Nontuberculous Mycobacteria
PubMed: 33565103
DOI: 10.1111/imr.12951 -
Environmental Science & Technology Nov 2022Microplastic (MP) contamination is a serious global environmental problem. Plastic contamination has attracted extensive attention during the past decades. While...
Microplastic (MP) contamination is a serious global environmental problem. Plastic contamination has attracted extensive attention during the past decades. While physiochemical weathering may influence the properties of MPs, biodegradation by microorganisms could ultimately mineralize plastics into CO. Compared to the well-studied marine ecosystems, the MP biodegradation process in riverine ecosystems, however, is less understood. The current study focuses on the MP biodegradation in one of the world's most plastic contaminated rivers, Pearl River, using micropolyethylene (mPE) as a model substrate. Mineralization of C-labeled mPE into CO provided direct evidence of mPE biodegradation by indigenous microorganisms. Several genera were identified as putative mPE degraders. Furthermore, two isolates related to the putative mPE degraders, sp. mPE3 and sp. mPE12, were retrieved, and their ability to mineralize C-mPE into CO was confirmed. Pangenomic analysis reveals that the genes related to the proposed mPE biodegradation pathway are shared by members of . While both and are known for their pathogenicity, these populations on the plastisphere in this study were likely nonpathogenic as they lacked virulence factors. The current study provided direct evidence for MP mineralization by indigenous biodegraders and predicted their biodegradation pathway, which may be harnessed to improve bioremediation of MPs in urban rivers.
Topics: Plastics; Ecosystem; Environmental Monitoring; Water Pollutants, Chemical; Mycobacteriaceae; Carbon Dioxide; Rivers
PubMed: 36288260
DOI: 10.1021/acs.est.2c05346 -
Microbiology and Molecular Biology... Nov 2020Pathogenic mycobacteria cause chronic and acute diseases ranging from human tuberculosis (TB) to nontubercular infections. causes both acute and chronic human... (Review)
Review
Pathogenic mycobacteria cause chronic and acute diseases ranging from human tuberculosis (TB) to nontubercular infections. causes both acute and chronic human tuberculosis. Environmentally acquired nontubercular mycobacteria (NTM) cause chronic disease in humans and animals. Not surprisingly, NTM and often use shared molecular mechanisms to survive within the host. The ESX-1 system is a specialized secretion system that is essential for virulence and is functionally conserved between and is an NTM found in both salt water and freshwater that is often used to study mycobacterial virulence. Since the discovery of the secretion system in 2003, the use of both and has defined the conserved molecular mechanisms underlying protein secretion and the lytic and regulatory activities of the ESX-1 system. Here, we review the trajectory of the field, including key discoveries regarding the ESX-1 system. We highlight the contributions of studies and the conserved and unique aspects of the ESX-1 secretion system.
Topics: Animals; Bacterial Proteins; Gene Expression Regulation, Bacterial; Host-Pathogen Interactions; Humans; Models, Biological; Mycobacterium marinum; Mycobacterium tuberculosis; Protein Transport; Tuberculosis; Type VII Secretion Systems; Virulence
PubMed: 32878966
DOI: 10.1128/MMBR.00082-19 -
Journal of Travel Medicine Jan 2021Medical tourism has been increasing dramatically globally, with people travelling from developed countries to low-income or middle-income countries, often to avoid high... (Review)
Review
BACKGROUND
Medical tourism has been increasing dramatically globally, with people travelling from developed countries to low-income or middle-income countries, often to avoid high costs or long delays associated with seeking healthcare in their countries of origin. The current review summarizes healthcare-related infections associated with medical tourism, focusing on cosmetic surgery and organ transplantation.
METHODS
A systematic MEDLINE and PubMed search from January 2010 to December 2019 yielded 80 relevant articles, including 49 articles on medical tourism-related infections focusing on cosmetic surgery and organ transplantation, which were included in this reviews.
RESULTS
The literature reveals specific types of cross-border, healthcare-related infections depending on medical intervention. Destinations include low-income countries such as countries of Asia and the Indian subcontinent, middle-income countries including Central and South America, and high-income countries such as the United States and Europe. In terms of type of infections, in 36 (68%) and 15 (28.3%) studies, wound and blood-borne infections were documented, respectively, while in 21 studies (58.3%) non-tuberculous mycobacteria were isolated, including Mycobacterium abscessus, Mycobacterium chelonae, Mycobacterium senegalense and Mycobacterium fortuitum. The choices of medical tourists could have significant consequences for them and their home countries, including infectious complications and importation of pathogens, particularly antibiotic-resistant microorganisms, with public health implications.
CONCLUSIONS
There is a need for public health strategies in order to prevent morbidity and mortality as well as future management and education of patients engaging in medical tourism.
Topics: Asia; Europe; Humans; Medical Tourism; Mycobacteriaceae; South America; Tourism; United States
PubMed: 33159509
DOI: 10.1093/jtm/taaa210 -
Microbiology Spectrum Oct 2014Bacteria have a natural propensity to grow as sessile, matrix-encapsulated, multicellular communities called biofilms. Formation of biofilms proceeds through genetically... (Review)
Review
Bacteria have a natural propensity to grow as sessile, matrix-encapsulated, multicellular communities called biofilms. Formation of biofilms proceeds through genetically programmed, distinct developmental stages signaled by intricate networks of communication among the constituent population and their environment. Growing in the complex and heterogeneous microenvironments of biofilms, the resident bacteria acquire unique phenotypes that are generally not associated with their planktonic counterparts. Most notable among these is an extraordinary level of tolerance to a variety of environmental stresses, including antibiotics. Although mycobacteria have long been observed to spontaneously form complex multicellular structures in vitro, it has only recently become apparent that these structures are not only formed through dedicated genetic pathways but are also tolerant to antibiotics. In this article, we review the recent advances in the understanding of mycobacterial biofilms in vitro. We further consider the possible linkage between biofilm-like lifestyles and characteristic persistence of mycobacterial infections against host-defense mechanisms as well as antibiotics.
Topics: Antitubercular Agents; Biofilms; Drug Tolerance; Immune Evasion; Mycobacterium
PubMed: 26104368
DOI: 10.1128/microbiolspec.MGM2-0004-2013 -
Advances in Experimental Medicine and... 2017Genome-based insights into the evolution of Mycobacterium tuberculosis and other tuberculosis-causing mycobacteria are constantly increasing. In particular, the recent... (Review)
Review
Genome-based insights into the evolution of Mycobacterium tuberculosis and other tuberculosis-causing mycobacteria are constantly increasing. In particular, the recent genomic and functional characterization of several Myocbacterium canettii strains, which are thought to resemble in many aspects the putative common ancestor of the members of the M. tuberculosis complex (MTBC), has consolidated a plausible scenario of the early evolution of tuberculosis-causing mycobacteria, in which the clonal MTBC, comprising numerous key pathogens of mammalian hosts, has evolved from a generalist mycobacterium living in the environment. These studies also have considerably enriched our knowledge on selected molecular events that likely have contributed to the incursion, maintenance and spread of the MTBC members in diverse mammalian hosts. Here, we summarize and discuss recently revealed molecular and evolutionary aspects and emphasize the vast utility of M. canettii strains for identifying the mechanisms that contributed to the global emergence of M. tuberculosis as one of the most important human pathogens.
Topics: Animals; Biological Evolution; Genome, Bacterial; Humans; Mycobacterium; Mycobacterium Infections; Mycobacterium tuberculosis; Phylogeny; Phylogeography; Virulence
PubMed: 29116628
DOI: 10.1007/978-3-319-64371-7_2 -
Emerging Infectious Diseases Aug 2023Mycolicibacterium neoaurum is a rapidly growing mycobacterium and an emerging cause of human infections. M. neoaurum infections are uncommon but likely underreported,... (Review)
Review
Mycolicibacterium neoaurum is a rapidly growing mycobacterium and an emerging cause of human infections. M. neoaurum infections are uncommon but likely underreported, and our understanding of the disease spectrum and optimum management is incomplete. We summarize demographic and clinical characteristics of a case of catheter-related M. neoaurum bacteremia in a child with leukemia and those of 36 previously reported episodes of M. neoaurum infection. Most infections occurred in young to middle-aged adults with serious underlying medical conditions and commonly involved medical devices. Overall, infections were not associated with severe illness or death. In contrast to other mycobacteria species, M. neoaurum was generally susceptible to multiple antimicrobial drugs and responded promptly to treatment, and infections were associated with good outcomes after relatively short therapy duration and device removal. Delays in identification and susceptibility testing were common. We recommend using combination antimicrobial drug therapy and removal of infected devices to eradicate infection.
Topics: Child; Humans; Middle Aged; Cross Infection; Delivery of Health Care; Mycobacteriaceae; Mycobacterium; Mycobacterium Infections; Young Adult
PubMed: 37486155
DOI: 10.3201/eid2908.230007 -
Frontiers in Immunology 2022complex (MAC) is the main causative agent of infectious diseases in humans among nontuberculous mycobacteria (NTM) that are ubiquitous organisms found in environmental... (Review)
Review
complex (MAC) is the main causative agent of infectious diseases in humans among nontuberculous mycobacteria (NTM) that are ubiquitous organisms found in environmental media such as soil as well as in domestic and natural waters. MAC is a primary causative agent of NTM-lung disease that threaten immunocompromised or structural lung disease patients. The incidence and the prevalence of infection have been reduced, while MAC infections and mortality rates have increased, making it a cause of global health concern. The emergence of drug resistance and the side effects of long-term drug use have led to a poor outcome of treatment regimens against MAC infections. Therefore, the development of host-directed therapy (HDT) has recently gained interest, aiming to accelerate mycobacterial clearance and reversing lung damage by employing the immune system using a novel adjuvant strategy to improve the clinical outcome of MAC infection. Therefore, in this review, we discuss the innate immune responses that contribute to MAC infection focusing on macrophages, chief innate immune cells, and host susceptibility factors in patients. We also discuss potential HDTs that can act on the signaling pathway of macrophages, thereby contributing to antimycobacterial activity as a part of the innate immune response during MAC infection. Furthermore, this review provides new insights into MAC infection control that modulates and enhances macrophage function, promoting host antimicrobial activity in response to potential HDTs and thus presenting a deeper understanding of the interactions between macrophages and MACs during infection.
Topics: Humans; Mycobacterium avium Complex; Mycobacterium avium-intracellulare Infection; Macrophages; Nontuberculous Mycobacteria; Mycobacterium tuberculosis; Lung Diseases
PubMed: 36505429
DOI: 10.3389/fimmu.2022.931876 -
Cell Chemical Biology Feb 2016When it comes to lipid diversity, no bacterial genus approaches Mycobacterium. In this issue of Cell Chemical Biology, Burbaud et al. (2016) provide a multi-genic...
When it comes to lipid diversity, no bacterial genus approaches Mycobacterium. In this issue of Cell Chemical Biology, Burbaud et al. (2016) provide a multi-genic working model for the biosynthesis of trehalose polyphleate (TPP), one of the largest known lipids in mycobacteria. They demonstrate that this lipid is made by diverse mycobacterial species, including those of medical importance.
Topics: Lipids; Membrane Lipids; Mycobacterium; Mycobacterium Infections; Mycobacterium bovis; Mycobacterium tuberculosis; Trehalose
PubMed: 26971870
DOI: 10.1016/j.chembiol.2016.02.004 -
Journal of Veterinary Diagnostic... Jan 2022Two aborted Chester White pig fetuses were presented to a veterinary diagnostic laboratory in Illinois. Postmortem examination identified no gross abnormalities....
Two aborted Chester White pig fetuses were presented to a veterinary diagnostic laboratory in Illinois. Postmortem examination identified no gross abnormalities. Histologic evaluation revealed multifocal necrosis of chorionic epithelial cells, coalescing areas of mineralization in the placenta, and focal accumulations of viable and degenerate neutrophils in the lung. Intra- and extracellular acid-fast bacilli were identified in the lesions in both the placenta and lungs. Bacterial culture of stomach contents yielded heavy growth of , a rapidly growing nontuberculous mycobacterium (NTM), which was further confirmed through whole-genome sequencing. NTM are opportunistic pathogens commonly found in the soil and in contaminated water supplies. In animals, is typically introduced through cutaneous wounds leading to infections limited to the skin, with systemic infection being uncommon. To our knowledge, abortion caused by has not been reported previously.
Topics: Animals; Calcinosis; Cell Count; Epithelial Cells; Female; Mycobacterium fortuitum; Nontuberculous Mycobacteria; Swine; Swine Diseases
PubMed: 34448422
DOI: 10.1177/10406387211042289