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1.
Susceptibility for Some Infectious Diseases in Patients With Diabetes: The Key Role of Glycemia.
Chávez-Reyes, J, Escárcega-González, CE, Chavira-Suárez, E, León-Buitimea, A, Vázquez-León, P, Morones-Ramírez, JR, Villalón, CM, Quintanar-Stephano, A, Marichal-Cancino, BA
Frontiers in public health. 2021;:559595
Abstract
Uncontrolled diabetes results in several metabolic alterations including hyperglycemia. Indeed, several preclinical and clinical studies have suggested that this condition may induce susceptibility and the development of more aggressive infectious diseases, especially those caused by some bacteria (including Chlamydophila pneumoniae, Haemophilus influenzae, and Streptococcus pneumoniae, among others) and viruses [such as coronavirus 2 (CoV2), Influenza A virus, Hepatitis B, etc.]. Although the precise mechanisms that link glycemia to the exacerbated infections remain elusive, hyperglycemia is known to induce a wide array of changes in the immune system activity, including alterations in: (i) the microenvironment of immune cells (e.g., pH, blood viscosity and other biochemical parameters); (ii) the supply of energy to infectious bacteria; (iii) the inflammatory response; and (iv) oxidative stress as a result of bacterial proliferative metabolism. Consistent with this evidence, some bacterial infections are typical (and/or have a worse prognosis) in patients with hypercaloric diets and a stressful lifestyle (conditions that promote hyperglycemic episodes). On this basis, the present review is particularly focused on: (i) the role of diabetes in the development of some bacterial and viral infections by analyzing preclinical and clinical findings; (ii) discussing the possible mechanisms by which hyperglycemia may increase the susceptibility for developing infections; and (iii) further understanding the impact of hyperglycemia on the immune system.
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2.
Epidermis as a Platform for Bacterial Transmission.
Baquero, F, Saralegui, C, Marcos-Mencía, D, Ballestero, L, Vañó-Galván, S, Moreno-Arrones, ÓM, Del Campo, R
Frontiers in immunology. 2021;:774018
Abstract
The epidermis constitutes a continuous external layer covering the body, offering protection against bacteria, the most abundant living organisms that come into contact with this barrier. The epidermis is heavily colonized by commensal bacterial organisms that help protect against pathogenic bacteria. The highly regulated and dynamic interaction between the epidermis and commensals involves the host's production of nutritional factors promoting bacterial growth together to chemical and immunological bacterial inhibitors. Signal trafficking ensures the system's homeostasis; conditions that favor colonization by pathogens frequently foster commensal growth, thereby increasing the bacterial population size and inducing the skin's antibacterial response, eliminating the pathogens and re-establishing the normal density of commensals. The microecological conditions of the epidermis favors Gram-positive organisms and are unsuitable for long-term Gram-negative colonization. However, the epidermis acts as the most important host-to-host transmission platform for bacteria, including those that colonize human mucous membranes. Bacteria are frequently shared by relatives, partners, and coworkers. The epidermal bacterial transmission platform of healthcare workers and visitors can contaminate hospitalized patients, eventually contributing to cross-infections. Epidermal transmission occurs mostly via the hands and particularly through fingers. The three-dimensional physical structure of the epidermis, particularly the fingertips, which have frictional ridges, multiplies the possibilities for bacterial adhesion and release. Research into the biology of bacterial transmission via the hands is still in its infancy; however, tribology, the science of interacting surfaces in relative motion, including friction, wear and lubrication, will certainly be an important part of it. Experiments on finger-to-finger transmission of microorganisms have shown significant interindividual differences in the ability to transmit microorganisms, presumably due to genetics, age, sex, and the gland density, which determines the physical, chemical, adhesive, nutritional, and immunological status of the epidermal surface. These studies are needed to optimize interventions and strategies for preventing the hand transmission of microorganisms.
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3.
Scavenging Bacterial Siderophores with Engineered Lipocalin Proteins as an Alternative Antimicrobial Strategy.
Dauner, M, Skerra, A
Chembiochem : a European journal of chemical biology. 2020;(5):601-606
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Abstract
Iron acquisition mediated by siderophores, high-affinity chelators for which bacteria have evolved specific synthesis and uptake mechanisms, plays a crucial role in microbiology and in host-pathogen interactions. In the ongoing fight against bacterial infections, this area has attracted biomedical interest. Beyond several approaches to interfere with siderophore-mediated iron uptake from medicinal and immunochemistry, the development of high-affinity protein scavengers that tightly complex the siderophores produced by pathogenic bacteria has appeared as a novel strategy. Such binding proteins have been engineered based on siderocalin-also known as lipocalin 2-an endogenous human scavenger of enterobactin and bacillibactin that controls the systemic spreading of commensal bacteria such as Escherichia coli. By using combinatorial protein design, siderocalin was reshaped to bind several siderophores from Pseudomonas aeruginosa and, in particular, petrobactin from Bacillus anthracis, none of which is recognized by the natural protein. Such engineered versions of siderocalin effectively suppress the growth of corresponding pathogenic bacteria by depriving them of their iron supply and offer the potential to complement antibiotic therapy in situations of acute or persistent infection.
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4.
Recent Advances in Oral Nano-Antibiotics for Bacterial Infection Therapy.
Wu, ZL, Zhao, J, Xu, R
International journal of nanomedicine. 2020;:9587-9610
Abstract
Bacterial infections are the main infectious diseases and cause of death worldwide. Antibiotics are used to treat various infections ranging from minor to life-threatening ones. The dominant route to administer antibiotics is through oral delivery and subsequent gastrointestinal tract (GIT) absorption. However, the delivery efficiency is limited by many factors such as low drug solubility and/or permeability, gastrointestinal instability, and low antibacterial activity. Nanotechnology has emerged as a novel and efficient tool for targeting drug delivery, and a number of promising nanotherapeutic strategies have been widely explored to overcome these obstacles. In this review, we explore published studies to provide a comprehensive understanding of the recent progress in the area of orally deliverable nano-antibiotic formulations. The first part of this article discusses the functions and underlying mechanisms by which nanomedicines increase the oral absorption of antibiotics. The second part focuses on the classification of oral nano-antibiotics and summarizes the advantages, disadvantages and applications of nanoformulations including lipid, polymer, nanosuspension, carbon nanotubes and mesoporous silica nanoparticles in oral delivery of antibiotics. Lastly, the challenges and future perspective of oral nano-antibiotics for infection disease therapy are discussed. Overall, nanomedicines designed for oral drug delivery system have demonstrated the potential for the improvement and optimization of currently available antibiotic therapies.
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5.
The Role of Proteases in the Virulence of Plant Pathogenic Bacteria.
Figaj, D, Ambroziak, P, Przepiora, T, Skorko-Glonek, J
International journal of molecular sciences. 2019;(3)
Abstract
A pathogenic lifestyle is inextricably linked with the constant necessity of facing various challenges exerted by the external environment (both within and outside the host). To successfully colonize the host and establish infection, pathogens have evolved sophisticated systems to combat the host defense mechanisms and also to be able to withstand adverse environmental conditions. Proteases, as crucial components of these systems, are involved in a variety of processes associated with infection. In phytopathogenic bacteria, they play important regulatory roles and modulate the expression and functioning of various virulence factors. Secretory proteases directly help avoid recognition by the plant immune systems, and contribute to the deactivation of the defense response pathways. Finally, proteases are important components of protein quality control systems, and thus enable maintaining homeostasis in stressed bacterial cells. In this review, we discuss the known protease functions and protease-regulated signaling processes associated with virulence of plant pathogenic bacteria.
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6.
Diet-Microbe-Host Interactions That Affect Gut Mucosal Integrity and Infection Resistance.
Forgie, AJ, Fouhse, JM, Willing, BP
Frontiers in immunology. 2019;:1802
Abstract
The gastrointestinal tract microbiome plays a critical role in regulating host innate and adaptive immune responses against pathogenic bacteria. Disease associated dysbiosis and environmental induced insults, such as antibiotic treatments can lead to increased susceptibility to infection, particularly in a hospital setting. Dietary intervention is the greatest tool available to modify the microbiome and support pathogen resistance. Some dietary components can maintain a healthy disease resistant microbiome, whereas others can contribute to an imbalanced microbial population, impairing intestinal barrier function and immunity. Characterizing the effects of dietary components through the host-microbe axis as it relates to gastrointestinal health is vital to provide evidence-based dietary interventions to mitigate infections. This review will cover the effect of dietary components (carbohydrates, fiber, proteins, fats, polyphenolic compounds, vitamins, and minerals) on intestinal integrity and highlight their ability to modulate host-microbe interactions as to improve pathogen resistance.
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7.
Body mass index and the risk of infection - from underweight to obesity.
Dobner, J, Kaser, S
Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases. 2018;(1):24-28
Abstract
BACKGROUND Nutritional status is a well-known risk factor for metabolic and endocrine disorders. Recent studies suggest that dietary intake also affects immune function and as a consequence infection risk. AIMS This reviews aims to give an overview on the effect of body weight on infection rate at different periods of life. SOURCES Clinically relevant prospective, cross-sectional and case-control community-based studies are summarized. CONTENT In children and adolescents underweight is a significant risk factor for infection especially in developing countries, probably reflecting malnutrition and poor hygienic standards. Data from industrialized countries suggest that infection rate is also increased in obese children and adolescents. Similarly, several studies suggest a U-shaped increased infection rate in both underweight and obese adults. In the latter, infections of the skin and respiratory tract as well as surgical-site infections have consistently been reported to be more common than in normal-weight participants. Paradoxically, mortality of critically ill patients was reduced in obesity in some studies. IMPLICATIONS Several studies in children or adults suggest that both underweight and obesity are associated with increased infection risk. However, confounding factors such as malnutrition, hygienic status and underlying disease or co-morbidities might aggravate accurate assessment of the impact of body weight on infection risk.
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Bioactivities of Phenolics by Focusing on Suppression of Chronic Diseases: A Review.
Shahidi, F, Yeo, J
International journal of molecular sciences. 2018;(6)
Abstract
Phenolics, which are secondary metabolites of plants, exhibit remarkable bioactivities. In this contribution, we have focused on their protective effect against chronic diseases rather than their antioxidant activities, which have been widely discussed in the literature. A large body of epidemiological studies has proven the bioactivities of phenolics in both standard compounds and natural extracts: namely, anticancer, anti-inflammatory, and antibacterial activities as well as reducing diabetes, cardiovascular disease, and neurodegenerative disease. Phenolics also display anti-analgesic, anti-allergic, and anti-Alzheimer's properties. Thus, this review provides crucial information for better understanding the bioactivities of phenolics in foods and fills a gap in the existing collective and overall knowledge in the field.
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Nanocoatings for Chronic Wound Repair-Modulation of Microbial Colonization and Biofilm Formation.
Mihai, MM, Preda, M, Lungu, I, Gestal, MC, Popa, MI, Holban, AM
International journal of molecular sciences. 2018;(4)
Abstract
Wound healing involves a complex interaction between immunity and other natural host processes, and to succeed it requires a well-defined cascade of events. Chronic wound infections can be mono- or polymicrobial but their major characteristic is their ability to develop a biofilm. A biofilm reduces the effectiveness of treatment and increases resistance. A biofilm is an ecosystem on its own, enabling the bacteria and the host to establish different social interactions, such as competition or cooperation. With an increasing incidence of chronic wounds and, implicitly, of chronic biofilm infections, there is a need for alternative therapeutic agents. Nanotechnology shows promising openings, either by the intrinsic antimicrobial properties of nanoparticles or their function as drug carriers. Nanoparticles and nanostructured coatings can be active at low concentrations toward a large variety of infectious agents; thus, they are unlikely to elicit emergence of resistance. Nanoparticles might contribute to the modulation of microbial colonization and biofilm formation in wounds. This comprehensive review comprises the pathogenesis of chronic wounds, the role of chronic wound colonization and infection in the healing process, the conventional and alternative topical therapeutic approaches designed to combat infection and stimulate healing, as well as revolutionizing therapies such as nanotechnology-based wound healing approaches.
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10.
Role of divalent metals in infectious disease susceptibility and outcome.
Weiss, G, Carver, PL
Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases. 2018;(1):16-23
Abstract
BACKGROUND Divalent metals play important roles in maintaining metabolism and cellular growth of both eukaryotic hosts and invading microbes. Both metal deficiency and overload can result in abnormal cellular function or damage. Given its central role in host-pathogen interactions, subtle alterations of divalent metal homeostasis can occur in the course of infectious diseases which aim, from the host perspective, either to reduce the availability of respective metals to microbes or to use toxic metal accumulation to eliminate pathogens. AIMS To provide the reader with background information and clinical data on divalent metal homeostasis in host-pathogen interactions, how this affects the course of infectious disease and whether correction of metal disturbances has shown benefit in infections. SOURCES An in-depth analysis of PubMed articles related to the topic of this review published in English between 1970 and 2016 was performed. CONTENT From the microbial perspective, divalent metals are essential for growth and pathogenicity and to mount effective protection against antimicrobial host responses, including toxic radical formation. Microbes have evolved multiple strategies to control their access to divalent metals. From the clinical perspective, alterations of divalent metal levels may result in increased or decreased susceptibility to infection and often occur in response to infections. However, keeping in mind the strategies underlying such alterations, for which the term 'nutritional immunity' was coined, the uncritical correction of such divalent metal imbalances may cause harm to patients. This review addresses the role of the divalent metals iron, selenium, zinc, manganese and copper in infectious diseases from a mechanistic and clinical perspective. IMPLICATIONS We point out areas of research needed to expand our limited knowledge, hoping to improve the clinical management of patients with infections and to identify promising new targets for treatment by modulation of host or microbe divalent metal metabolism.