Interactions of plasma-activated water with biofilms: inactivation, dispersal effects and mechanisms of action. - Related Documents




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915401.0000Interactions of plasma-activated water with biofilms: inactivation, dispersal effects and mechanisms of action. Biofilms have several characteristics that ensure their survival in a range of adverse environmental conditions, including high cell numbers, close cell proximity to allow easy genetic exchange (e.g., for resistance genes), cell communication and protection through the production of an exopolysaccharide matrix. Together, these characteristics make it difficult to kill undesirable biofilms, despite the many studies aimed at improving the removal of biofilms. An elimination method that is safe, easy to deliver in physically complex environments and not prone to microbial resistance is highly desired. Cold atmospheric plasma, a lightning-like state generated from air or other gases with a high voltage can be used to make plasma-activated water (PAW) that contains many active species and radicals that have antimicrobial activity. Recent studies have shown the potential for PAW to be used for biofilm elimination without causing the bacteria to develop significant resistance. However, the precise mode of action is still the subject of debate. This review discusses the formation of PAW generated species and their impacts on biofilms. A focus is placed on the diffusion of reactive species into biofilms, the formation of gradients and the resulting interaction with the biofilm matrix and specific biofilm components. Such an understanding will provide significant benefits for tackling the ubiquitous problem of biofilm contamination in food, water and medical areas.202133504802
943010.9999Mechanisms of antimicrobial resistance in biofilms. Most bacteria in nature exist in aggregated communities known as biofilms, and cells within a biofilm demonstrate major physiological changes compared to their planktonic counterparts. Biofilms are associated with many different types of infections which can have severe impacts on patients. Infections involving a biofilm component are often chronic and highly recalcitrant to antibiotic therapy as a result of intrinsic physical factors including extracellular matrix production, low growth rates, altered antibiotic target production and efficient exchange of resistance genes. This review describes the biofilm lifecycle, phenotypic characteristics of a biofilm, and contribution of matrix and persister cells to biofilms intrinsic tolerance to antimicrobials. We also describe how biofilms can evolve antibiotic resistance and transfer resistance genes within biofilms. Multispecies biofilms and the impacts of various interactions, including cooperation and competition, between species on tolerance to antimicrobials in polymicrobial biofilm communities are also discussed.202439364333
862620.9998Challenges Associated With the Use of Metal and Metal Oxide Nanoparticles as Antimicrobial Agents: A Review of Resistance Mechanisms and Environmental Implications. The use of metal and metal oxide nanoparticles has been suggested as a means of combating antibiotic-resistant bacteria (ARB). This is due to the ability of nanoparticles to target numerous sites inside the bacterial cell. Microbes can, however, develop a resistance to hazardous environments. Soil microorganisms have evolved resistance to specific metals in soil by employing alternative survival strategies, like those adopted against antibiotics. Because of this survival mechanism, bacteria have been able to develop defense mechanisms to deal with metallic nanoparticles. Resistance has evolved in human pathogens to therapies that use metallic nanoparticles, such as silver nanoparticles. Metallic nanoparticles and antibiotics have currently been proven to be ineffective against several infections. Due to these concerns, scientists are investigating whether nanoparticles might cause environmental harm and potentially breed microbes that are resistant to both inorganic and organic nanoparticles. The increased use of inorganic nanoparticles has thus been shown to result in contaminations in wastewater, facilitating horizontal gene transfer among bacterial populations. The resistance mechanism of metallic nanoparticles, role in antibiotic resistance, and a potential solution to the environment's toxicity from nanoparticles are all discussed in this review.202540711446
914030.9998Polyamine as a microenvironment factor in resistance to antibiotics. One of the main issues in modern medicine is the decrease in the efficacy of antibiotic therapy against resistant microorganisms. The advent of antimicrobial resistance has added significantly to the impact of infectious diseases, in number of infections, as well as added healthcare costs. The development of antibiotic tolerance and resistance is influenced by a variety of environmental variables, and it is important to identify these environmental factors as part of any strategy for combating antibiotic resistance. The review aims to emphasize that biogenic polyamines are one of such environmental cues that impacts the antibiotic resistance in bacteria. The biogenic polyamines can help bacteria acquire resistance to antibiotics either by regulating the level of number of porin channels in the outer membrane, by modifying the outer membrane liposaccharides or by protecting macromolecule from antibiotic stress. Thus, understanding the way polyamines function in bacteria can thus be beneficial while designing the drugs to combat diseases.202437339480
954940.9998Mechanism of escape from the antibacterial activity of metal-based nanoparticles in clinically relevant bacteria: A systematic review. The emergency of antibiotic-resistant bacteria in severe infections is increasing, especially in nosocomial environments. The ESKAPE group is of special importance in the groups of multi-resistant bacteria due to its high capacity to generate resistance to antibiotics and bactericides. Therefore, metal-based nanomaterials are an attractive alternative to combat them because they have been demonstrated to damage biomolecules in the bacterial cells. However, there is a concern about bacteria developing resistance to NPs and their harmful effects due to environmental accumulation. Therefore, this systematic review aims to report the clinically relevant bacteria that have developed resistance to the NPs. According to the results of this systematic review, various mechanisms to counteract the antimicrobial activity of various NP types have been proposed. These mechanisms can be grouped into the following categories: production of extracellular compounds, metal efflux pumps, ROS response, genetic changes, DNA repair, adaptative morphogenesis, and changes in the plasma membrane.202437907198
942950.9998Basic features of biofilms--why are they difficult therapeutic targets? The purpose of this paper is to review the basic features of biofilms associated with human infections and summarize why such biofilms are resistant to antimicrobial agents. The formation of most biofilms involves adherence of bacteria to a conditioned surface, growth and division of the attached bacteria, synthesis of a polymeric slime matrix, formation of a structured microbial community, and incorporation of other micro-organisms into the microbial mass. The transition of bacteria from free-floating (planktonic) to biofilm environments involves extensive up-regulation of genes associated with adherence. Micro-organisms in established biofilms engage in complex integrated activities involving activation and deactivation of genes that promote the survival of bacteria within the biofilm community. Mechanisms of the increased resistance of biofilm bacteria to antimicrobial agents may involve: (1) neutralization or consumption of the drug, (2) failure of the drug to completely penetrate the biofilm, (3) inability of the drug to affect metabolically inactive bacteria, and (4) presence of drug-resistant bacteria within biofilms.200416479852
942760.9998Polysaccharides' Structures and Functions in Biofilm Architecture of Antimicrobial-Resistant (AMR) Pathogens. Bacteria and fungi have developed resistance to the existing therapies such as antibiotics and antifungal drugs, and multiple mechanisms are mediating this resistance. Among these, the formation of an extracellular matrix embedding different bacterial cells, called biofilm, is an effective strategy through which bacterial and fungal cells are establishing a relationship in a unique environment. The biofilm provides them the possibility to transfer genes conferring resistance, to prevent them from desiccation and to impede the penetration of antibiotics or antifungal drugs. Biofilms are formed of several constituents including extracellular DNA, proteins and polysaccharides. Depending on the bacteria, different polysaccharides form the biofilm matrix in different microorganisms, some of them involved in the first stage of cells' attachment to surfaces and to each other, and some responsible for giving the biofilm structure resistance and stability. In this review, we describe the structure and the role of different polysaccharides in bacterial and fungal biofilms, we revise the analytical methods to characterize them quantitatively and qualitatively and finally we provide an overview of potential new antimicrobial therapies able to inhibit biofilm formation by targeting exopolysaccharides.202336835442
947270.9998Bacteriophage and Bacterial Susceptibility, Resistance, and Tolerance to Antibiotics. Bacteriophages, viruses that infect and replicate within bacteria, impact bacterial responses to antibiotics in complex ways. Recent studies using lytic bacteriophages to treat bacterial infections (phage therapy) demonstrate that phages can promote susceptibility to chemical antibiotics and that phage/antibiotic synergy is possible. However, both lytic and lysogenic bacteriophages can contribute to antimicrobial resistance. In particular, some phages mediate the horizontal transfer of antibiotic resistance genes between bacteria via transduction and other mechanisms. In addition, chronic infection filamentous phages can promote antimicrobial tolerance, the ability of bacteria to persist in the face of antibiotics. In particular, filamentous phages serve as structural elements in bacterial biofilms and prevent the penetration of antibiotics. Over time, these contributions to antibiotic tolerance favor the selection of resistance clones. Here, we review recent insights into bacteriophage contributions to antibiotic susceptibility, resistance, and tolerance. We discuss the mechanisms involved in these effects and address their impact on bacterial fitness.202235890320
953180.9998How to Evaluate Non-Growing Cells-Current Strategies for Determining Antimicrobial Resistance of VBNC Bacteria. Thanks to the achievements in sanitation, hygiene practices, and antibiotics, we have considerably improved in our ongoing battle against pathogenic bacteria. However, with our increasing knowledge about the complex bacterial lifestyles and cycles and their plethora of defense mechanisms, it is clear that the fight is far from over. One of these resistance mechanisms that has received increasing attention is the ability to enter a dormancy state termed viable but non-culturable (VBNC). Bacteria that enter the VBNC state, either through unfavorable environmental conditions or through potentially lethal stress, lose their ability to grow on standard enrichment media, but show a drastically increased tolerance against antimicrobials including antibiotics. The inability to utilize traditional culture-based methods represents a considerable experimental hurdle to investigate their increased antimicrobial resistance and impedes the development and evaluation of effective treatments or interventions against bacteria in the VBNC state. Although experimental approaches were developed to detect and quantify VBNCs, only a few have been utilized for antimicrobial resistance screening and this review aims to provide an overview of possible methodological approaches.202133530321
953790.9998Antimicrobial Resistance and Inorganic Nanoparticles. Antibiotics are being less effective, which leads to high mortality in patients with infections and a high cost for the recovery of health, and the projections that are had for the future are not very encouraging which has led to consider antimicrobial resistance as a global health problem and to be the object of study by researchers. Although resistance to antibiotics occurs naturally, its appearance and spread have been increasing rapidly due to the inappropriate use of antibiotics in recent decades. A bacterium becomes resistant due to the transfer of genes encoding antibiotic resistance. Bacteria constantly mutate; therefore, their defense mechanisms mutate, as well. Nanotechnology plays a key role in antimicrobial resistance due to materials modified at the nanometer scale, allowing large numbers of molecules to assemble to have a dynamic interface. These nanomaterials act as carriers, and their design is mainly focused on introducing the temporal and spatial release of the payload of antibiotics. In addition, they generate new antimicrobial modalities for the bacteria, which are not capable of protecting themselves. So, nanoparticles are an adjunct mechanism to improve drug potency by reducing overall antibiotic exposure. These nanostructures can overcome cell barriers and deliver antibiotics to the cytoplasm to inhibit bacteria. This work aims to give a general vision between the antibiotics, the nanoparticles used as carriers, bacteria resistance, and the possible mechanisms that occur between them.202134884695
9590100.9998Recent advances in phage defense systems and potential overcoming strategies. Bacteriophages are effective in the prevention and control of bacteria, and many phage products have been permitted and applied in the field. Because bacteriophages are expected to replace other antimicrobial agents like antibiotics, the antibacterial effect of bacteriophage has attracted widespread attention. Recently, the diversified defense systems discovered in the target host have become potential threats to the continued effective application of phages. Therefore, a systematic summary and in-depth illustration of the interaction between phages and bacteria is conducive to the development of this biological control approach. In this review, we introduce different defense systems in bacteria against phages and emphasize newly discovered defense mechanisms in recent years. Additionally, we draw attention to the striking resemblance between defense system genes and antibiotic resistance genes, which raises concerns about the potential transfer of phage defense systems within bacterial populations and its future impact on phage efficacy. Thus, attention should be given to the effects of phage defense genes in practical applications. This article is not exhaustive, but strategies to overcome phage defense systems are also discussed to further promote more efficient use of phages.202337037289
8344110.9998Role of environmental stresses in elevating resistance mutations in bacteria: Phenomena and mechanisms. Mutations are an important origin of antibiotic resistance in bacteria. While there is increasing evidence showing promoted resistance mutations by environmental stresses, no retrospective research has yet been conducted on this phenomenon and its mechanisms. Herein, we summarized the phenomena of stress-elevated resistance mutations in bacteria, generalized the regulatory mechanisms and discussed the environmental and human health implications. It is shown that both chemical pollutants, such as antibiotics and other pharmaceuticals, biocides, metals, nanoparticles and disinfection byproducts, and non-chemical stressors, such as ultraviolet radiation, electrical stimulation and starvation, are capable of elevating resistance mutations in bacteria. Notably, resistance mutations are more likely to occur under sublethal or subinhibitory levels of these stresses, suggesting a considerable environmental concern. Further, mechanisms for stress-induced mutations are summarized in several points, namely oxidative stress, SOS response, DNA replication and repair systems, RpoS regulon and biofilm formation, all of which are readily provoked by common environmental stresses. Given bacteria in the environment are confronted with a variety of unfavorable conditions, we propose that the stress-elevated resistance mutations are a universal phenomenon in the environment and represent a nonnegligible risk factor for ecosystems and human health. The present review identifies a need for taking into account the pollutants' ability to elevate resistance mutations when assessing their environmental and human health risks and highlights the necessity of including resistance mutations as a target to prevent antibiotic resistance evolution.202235691443
9153120.9998Mycoplasma Contamination of Cell Cultures: Vesicular Traffic in Bacteria and Control over Infectious Agents. Cell cultures are subject to contamination either with cells of other cultures or with microorganisms, including fungi, viruses, and bacteria. Mycoplasma contamination of cell cultures is of particular importance. Since cell cultures are used for the production of vaccines and physiologically active compounds, designing a system for controlling contaminants becomes topical for fundamental science and biotechnological production. The discovery of extracellular membrane vesicles in mycoplasmas makes it necessary to take into consideration the bacterial vesicular traffic in systems designed for controlling infectious agents. The extracellular vesicles of bacteria mediate the traffic of proteins and genes, participate in cell-to-cell interactions, as well as in the pathogenesis and development of resistance to antibiotics. The present review discusses the features of mycoplasmas, their extracellular vesicles, and the interaction between contaminants and eukaryotic cells. Furthermore, it provides an analysis of the problems associated with modern methods of diagnosis and eradication of mycoplasma contamination from cell cultures and prospects for their solution.201425349713
8342130.9997Inflammatory immunity and bacteriological perspectives: A new direction for copper treatment of sepsis. Copper is an essential trace element for all aerobic organisms because of its unique biological functions. In recent years, researchers have discovered that copper can induce cell death through various regulatory mechanisms, thereby inducing inflammation. Efforts have also been made to alter the chemical structure of copper to achieve either anticancer or anti-inflammatory effects. The copper ion can exhibit bactericidal effects by interfering with the integrity of the cell membrane and promoting oxidative stress. Sepsis is a systemic inflammatory response caused by infection. Some studies have revealed that copper is involved in the pathophysiological process of sepsis and is closely related to its prognosis. During the infection of sepsis, the body may enhance the antimicrobial effect by increasing the release of copper. However, to avoid copper poisoning, all organisms have evolved copper resistance genes. Therefore, further analysis of the complex relationship between copper and bacteria may provide new ideas and research directions for the treatment of sepsis.202438692229
9731140.9997Towards an understanding of the genetics of bacterial metal resistance. Many bacteria show great promise for use in metal recovery. However, the genetics of metal-leaching, accumulation-resistance, and oxidation/reduction mechanisms of these bacteria is still an area of research in its infancy. The introduction of such genes into bacteria of economic importance would have application in biomining and environmental bioremediation.19911366923
9152150.9997Pseudomonas aeruginosa biofilm sensitivity to biocides: use of hydrogen peroxide as model antimicrobial agent for examining resistance mechanisms. The biofilm mode of bacterial growth may be the preferred form of existence in nature. Because of the global impact of problematic biofilms, study of the mechanisms affording resistance to various biocides is of dire importance. Furthermore, understanding the physiological differences between biofilm and planktonic organisms ranks particularly high on the list of important and necessary research. Such contributions will only serve to broaden our knowledge base, especially regarding the development of better antimicrobials while also fine-tuning the use of current highly effective antimicrobials. Using H2O2 as a model oxidizing biocide, we demonstrate the marked resistance of biofilm bacteria relative to planktonic cells. Because many biocides are good oxidizing agents (e.g., H2O2, HOCl), understanding the mechanisms by which genes involved in combating oxidative stress are activated is important in determining the overall efficacy of such biocides. Future studies will focus on determining mechanisms of oxidative stress gene regulation in bacterial biofilms.199910547822
9146160.9997Emergence of microbial resistance against nanoparticles: Mechanisms and strategies. Antimicrobial nanoparticles have gained the status of a new generation of drugs that can kill bacterial pathogens by multiple means; however, nanoparticle resistance acquired by some bacterial pathogens has evoked a cause of concern. Several reports suggested that bacteria can develop nanoparticles, specifically metal nanoparticle resistance, by mechanisms: nanoparticle transformation-induced oxidative stress, membrane alterations, reversible adaptive resistance, irreversible modifications to cell division, and a change in bacterial motility and resistance. Surface properties, concentration and aggregation of nanoparticles, biofilm forming and metal exclusion capacity, and R plasmid and flagellin synthesis by bacteria are crucial factors in the development of nanoparticle resistance in bacteria. Studies reported the resistance reversal by modifying the surface corona of nanoparticles or inhibiting flagellin production by bacterial pathogens. Furthermore, strict regulation regarding the use and disposal of nano-waste across the globe, the firm knowledge of microbe-nanoparticle interaction, and the regulated disposal of nanoparticles in soil and water is required to prevent microbes from developing nanoparticle resistance.202336778867
9533170.9997The disparate effects of bacteriophages on antibiotic-resistant bacteria. Faced with the crisis of multidrug-resistant bacteria, bacteriophages, viruses that infect and replicate within bacteria, have been reported to have both beneficial and detrimental effects with respect to disease management. Bacteriophages (phages) have important ecological and evolutionary impacts on their bacterial hosts and have been associated with therapeutic use to kill bacterial pathogens, but can lead to the transmission of antibiotic resistance. Although the process known as transduction has been reported for many bacterial species by classic and modern genetic approaches, its contribution to the spread of antibiotic resistance in nature remains unclear. In addition, detailed molecular studies have identified phages residing in bacterial genomes, revealing unexpected interactions between phages and their bacterial hosts. Importantly, antibiotics can induce the production of phages and phage-encoded products, disseminating these viruses and virulence-related genes, which have dangerous consequences for disease severity. These unwanted side-effects of antibiotics cast doubt on the suitability of some antimicrobial treatments and may require new strategies to prevent and limit the selection for virulence. Foremost among these treatments is phage therapy, which could be used to treat many bacterial infectious diseases and confront the pressing problem of antibiotic resistance in pathogenic bacteria. This review discusses the interactions between bacteriophages, antibiotics, and bacteria and provides an integrated perspective that aims to inspire the development of successful antibacterial therapies.201830302018
9428180.9997Biofilms and their properties. Bacteria within the oral cavity live primarily as complex, polymicrobial biofilms. Dental biofilms are necessary etiological factors for dental caries and periodontal diseases but have also been implicated in diseases outside the oral cavity. Biofilm is the preferred lifestyle for bacteria, and biofilms are found on almost any surface in nature. Bacteria growing within a biofilm exhibit an altered phenotype. Substantial changes in gene expression occur when bacteria are in close proximity or physical contact with one another or with the host. This may facilitate nutritional co-operation, cell-cell signaling, and gene transfer, including transfer of antibiotic-resistance genes, thus rendering biofilm bacteria with properties other than those found in free-floating, planktonic bacteria. We will discuss biofilm properties and possible consequences for future prophylaxis.201830178559
9582190.9997Humans and Microbes: A Systems Theory Perspective on Coevolution. The issue of rapid adaptation of microorganisms to changing environments is examined. The mechanism of adaptive mutations is analyzed. The possibility that horizontal gene transfer is a random process is discussed. Bacteria, unicellular fungi, and other microorganisms successfully adapt to fast-changing conditions (such as exposure to drugs) because their evolution is not a random process. Adaptation to antibiotics, adaptive mutations, and related phenomena occur because microbial evolution is inherently directed and purposefully oriented toward potential external changes. Rejecting gene-centricity plays a crucial role in understanding the coevolution of humans and pathogens. This means that beyond genes, there exists a higher-level system-an organism with its own unique properties that cannot be reduced to genes. The problem of human adaptation to infectious agents (viruses, bacteria, and protozoa) is also analyzed. Based on general systems theory, it is concluded that humans and pathogens coevolve in a controlled manner.202541176022