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EMBO Reports Dec 2020Antimicrobial resistance (AMR) and persistence are associated with an elevated risk of treatment failure and relapsing infections. They are thus important drivers of... (Review)
Review
Antimicrobial resistance (AMR) and persistence are associated with an elevated risk of treatment failure and relapsing infections. They are thus important drivers of increased morbidity and mortality rates resulting in growing healthcare costs. Antibiotic resistance is readily identifiable with standard microbiological assays, and the threat imposed by antibiotic resistance has been well recognized. Measures aiming to reduce resistance development and spreading of resistant bacteria are being enforced. However, the phenomenon of bacteria surviving antibiotic exposure despite being fully susceptible, so-called antibiotic persistence, is still largely underestimated. In contrast to antibiotic resistance, antibiotic persistence is difficult to measure and therefore often missed, potentially leading to treatment failures. In this review, we focus on bacterial mechanisms allowing evasion of antibiotic killing and discuss their implications on human health. We describe the relationship between antibiotic persistence and bacterial heterogeneity and discuss recent studies that link bacterial persistence and tolerance with the evolution of antibiotic resistance. Finally, we review persister detection methods, novel strategies aiming at eradicating bacterial persisters and the latest advances in the development of new antibiotics.
Topics: Anti-Bacterial Agents; Bacteria; Drug Resistance, Bacterial; Drug Resistance, Microbial; Humans
PubMed: 33400359
DOI: 10.15252/embr.202051034 -
Microbiology Spectrum Apr 2016Emergence of resistance among the most important bacterial pathogens is recognized as a major public health threat affecting humans worldwide. Multidrug-resistant... (Review)
Review
Emergence of resistance among the most important bacterial pathogens is recognized as a major public health threat affecting humans worldwide. Multidrug-resistant organisms have not only emerged in the hospital environment but are now often identified in community settings, suggesting that reservoirs of antibiotic-resistant bacteria are present outside the hospital. The bacterial response to the antibiotic "attack" is the prime example of bacterial adaptation and the pinnacle of evolution. "Survival of the fittest" is a consequence of an immense genetic plasticity of bacterial pathogens that trigger specific responses that result in mutational adaptations, acquisition of genetic material, or alteration of gene expression producing resistance to virtually all antibiotics currently available in clinical practice. Therefore, understanding the biochemical and genetic basis of resistance is of paramount importance to design strategies to curtail the emergence and spread of resistance and to devise innovative therapeutic approaches against multidrug-resistant organisms. In this chapter, we will describe in detail the major mechanisms of antibiotic resistance encountered in clinical practice, providing specific examples in relevant bacterial pathogens.
Topics: Adaptation, Physiological; Anti-Bacterial Agents; Bacteria; Bacterial Infections; Drug Resistance, Microbial; Drug Resistance, Multiple, Bacterial; Humans; Mutation
PubMed: 27227291
DOI: 10.1128/microbiolspec.VMBF-0016-2015 -
Nature Reviews. Microbiology May 2022Antibiotic resistance is a global health challenge, involving the transfer of bacteria and genes between humans, animals and the environment. Although multiple barriers... (Review)
Review
Antibiotic resistance is a global health challenge, involving the transfer of bacteria and genes between humans, animals and the environment. Although multiple barriers restrict the flow of both bacteria and genes, pathogens recurrently acquire new resistance factors from other species, thereby reducing our ability to prevent and treat bacterial infections. Evolutionary events that lead to the emergence of new resistance factors in pathogens are rare and challenging to predict, but may be associated with vast ramifications. Transmission events of already widespread resistant strains are, on the other hand, common, quantifiable and more predictable, but the consequences of each event are limited. Quantifying the pathways and identifying the drivers of and bottlenecks for environmental evolution and transmission of antibiotic resistance are key components to understand and manage the resistance crisis as a whole. In this Review, we present our current understanding of the roles of the environment, including antibiotic pollution, in resistance evolution, in transmission and as a mere reflection of the regional antibiotic resistance situation in the clinic. We provide a perspective on current evidence, describe risk scenarios, discuss methods for surveillance and the assessment of potential drivers, and finally identify some actions to mitigate risks.
Topics: Animals; Anti-Bacterial Agents; Bacteria; Bacterial Infections; Drug Resistance, Bacterial; Drug Resistance, Microbial
PubMed: 34737424
DOI: 10.1038/s41579-021-00649-x -
Nature Nov 2019The problem of resistance to therapy in cancer is multifaceted. Here we take a reductionist approach to define and separate the key determinants of drug resistance,... (Review)
Review
The problem of resistance to therapy in cancer is multifaceted. Here we take a reductionist approach to define and separate the key determinants of drug resistance, which include tumour burden and growth kinetics; tumour heterogeneity; physical barriers; the immune system and the microenvironment; undruggable cancer drivers; and the many consequences of applying therapeutic pressures. We propose four general solutions to drug resistance that are based on earlier detection of tumours permitting cancer interception; adaptive monitoring during therapy; the addition of novel drugs and improved pharmacological principles that result in deeper responses; and the identification of cancer cell dependencies by high-throughput synthetic lethality screens, integration of clinico-genomic data and computational modelling. These different approaches could eventually be synthesized for each tumour at any decision point and used to inform the choice of therapy.
Topics: Antineoplastic Agents; Drug Resistance, Neoplasm; Humans; Models, Biological; Neoplasms; Tumor Microenvironment
PubMed: 31723286
DOI: 10.1038/s41586-019-1730-1 -
Brazilian Journal of Microbiology :... Dec 2021The assembly of microorganisms over a surface and their ability to develop resistance against available antibiotics are major concerns of interest. To survive against... (Review)
Review
The assembly of microorganisms over a surface and their ability to develop resistance against available antibiotics are major concerns of interest. To survive against harsh environmental conditions including known antibiotics, the microorganisms form a unique structure, referred to as biofilm. The mechanism of biofilm formation is triggered and regulated by quorum sensing, hostile environmental conditions, nutrient availability, hydrodynamic conditions, cell-to-cell communication, signaling cascades, and secondary messengers. Antibiotic resistance, escape of microbes from the body's immune system, recalcitrant infections, biofilm-associated deaths, and food spoilage are some of the problems associated with microbial biofilms which pose a threat to humans, veterinary, and food processing sectors. In this review, we focus in detail on biofilm formation, its architecture, composition, genes and signaling cascades involved, and multifold antibiotic resistance exhibited by microorganisms dwelling within biofilms. We also highlight different physical, chemical, and biological biofilm control strategies including those based on plant products. So, this review aims at providing researchers the knowledge regarding recent advances on the mechanisms involved in biofilm formation at the molecular level as well as the emergent method used to get rid of antibiotic-resistant and life-threatening biofilms.
Topics: Anti-Bacterial Agents; Bacterial Physiological Phenomena; Biofilms; Drug Resistance, Microbial; Quorum Sensing
PubMed: 34558029
DOI: 10.1007/s42770-021-00624-x -
International Journal of Molecular... May 2020Cancer is one of the main causes of death worldwide. Despite the significant development of methods of cancer healing during the past decades, chemotherapy still remains... (Review)
Review
Cancer is one of the main causes of death worldwide. Despite the significant development of methods of cancer healing during the past decades, chemotherapy still remains the main method for cancer treatment. Depending on the mechanism of action, commonly used chemotherapeutic agents can be divided into several classes (antimetabolites, alkylating agents, mitotic spindle inhibitors, topoisomerase inhibitors, and others). Multidrug resistance (MDR) is responsible for over 90% of deaths in cancer patients receiving traditional chemotherapeutics or novel targeted drugs. The mechanisms of MDR include elevated metabolism of xenobiotics, enhanced efflux of drugs, growth factors, increased DNA repair capacity, and genetic factors (gene mutations, amplifications, and epigenetic alterations). Rapidly increasing numbers of biomedical studies are focused on designing chemotherapeutics that are able to evade or reverse MDR. The aim of this review is not only to demonstrate the latest data on the mechanisms of cellular resistance to anticancer agents currently used in clinical treatment but also to present the mechanisms of action of novel potential antitumor drugs which have been designed to overcome these resistance mechanisms. Better understanding of the mechanisms of MDR and targets of novel chemotherapy agents should provide guidance for future research concerning new effective strategies in cancer treatment.
Topics: Animals; Antineoplastic Agents; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Gene Expression Regulation, Neoplastic; Humans; Neoplasms; Pharmacogenetics
PubMed: 32370233
DOI: 10.3390/ijms21093233 -
Frontiers in Cellular and Infection... 2022Both, antibiotic persistence and antibiotic resistance characterize phenotypes of survival in which a bacterial cell becomes insensitive to one (or even) more... (Review)
Review
Both, antibiotic persistence and antibiotic resistance characterize phenotypes of survival in which a bacterial cell becomes insensitive to one (or even) more antibiotic(s). However, the molecular basis for these two antibiotic-tolerant phenotypes is fundamentally different. Whereas antibiotic resistance is genetically determined and hence represents a rather stable phenotype, antibiotic persistence marks a transient physiological state triggered by various stress-inducing conditions that switches back to the original antibiotic sensitive state once the environmental situation improves. The molecular basics of antibiotic resistance are in principle well understood. This is not the case for antibiotic persistence. Under all culture conditions, there is a stochastically formed, subpopulation of persister cells in bacterial populations, the size of which depends on the culture conditions. The proportion of persisters in a bacterial population increases under different stress conditions, including treatment with bactericidal antibiotics (BCAs). Various models have been proposed to explain the formation of persistence in bacteria. We recently hypothesized that all physiological culture conditions leading to persistence converge in the inability of the bacteria to re-initiate a new round of DNA replication caused by an insufficient level of the initiator complex ATP-DnaA and hence by the lack of formation of a functional orisome. Here, we extend this hypothesis by proposing that in this persistence state the bacteria become more susceptible to mutation-based antibiotic resistance provided they are equipped with error-prone DNA repair functions. This is - in our opinion - in particular the case when such bacterial populations are exposed to BCAs.
Topics: Anti-Bacterial Agents; Bacteria; Drug Resistance, Bacterial; Drug Resistance, Microbial
PubMed: 35928205
DOI: 10.3389/fcimb.2022.900848 -
The Yale Journal of Biology and Medicine Mar 2017Undoubtedly, the discovery of penicillin is one of the greatest milestones in modern medicine. 2016 marks the 75th anniversary of the first systemic administration of... (Review)
Review
Undoubtedly, the discovery of penicillin is one of the greatest milestones in modern medicine. 2016 marks the 75th anniversary of the first systemic administration of penicillin in humans, and is therefore an occasion to reflect upon the extraordinary impact that penicillin has had on the lives of millions of people since. This perspective presents a historical account of the discovery of the wonder drug, describes the biological nature of penicillin, and considers lessons that can be learned from the golden era of antibiotic research, which took place between the 1940s and 1960s. Looking back at the history of penicillin might help us to relive this journey to find new treatments and antimicrobial agents. This is particularly relevant today as the emergence of multiple drug resistant bacteria poses a global threat, and joint efforts are needed to combat the rise and spread of resistance.
Topics: Anti-Bacterial Agents; Anti-Infective Agents; Drug Resistance, Microbial; Drug Resistance, Multiple, Bacterial; Humans; Penicillins
PubMed: 28356901
DOI: No ID Found -
Molecules (Basel, Switzerland) Jan 2022Multidrug resistance is a leading concern in public health. It describes a complex phenotype whose predominant feature is resistance to a wide range of structurally... (Review)
Review
Multidrug resistance is a leading concern in public health. It describes a complex phenotype whose predominant feature is resistance to a wide range of structurally unrelated cytotoxic compounds, many of which are anticancer agents. Multidrug resistance may be also related to antimicrobial drugs, and is known to be one of the most serious global public health threats of this century. Indeed, this phenomenon has increased both mortality and morbidity as a consequence of treatment failures and its incidence in healthcare costs. The large amounts of antibiotics used in human therapies, as well as for farm animals and even for fishes in aquaculture, resulted in the selection of pathogenic bacteria resistant to multiple drugs. It is not negligible that the ongoing COVID-19 pandemic may further contribute to antimicrobial resistance. In this paper, multidrug resistance and antimicrobial resistance are underlined, focusing on the therapeutic options to overcome these obstacles in drug treatments. Lastly, some recent studies on nanodrug delivery systems have been reviewed since they may represent a significant approach for overcoming resistance.
Topics: Animals; Drug Resistance, Microbial; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Humans; Nanoparticle Drug Delivery System
PubMed: 35163878
DOI: 10.3390/molecules27030616 -
International Microbiology : the... Nov 2021We are living in a society of fear, where the objectivity in estimating risks is distorted by the media and the interested parties. During more than half of a century,... (Review)
Review
We are living in a society of fear, where the objectivity in estimating risks is distorted by the media and the interested parties. During more than half of a century, the feeling of antibiotic resistance as an apocalyptic phenomenon able to push our society to the high mortality rates caused by infectious diseases in the dark pre-antibiotic ages has been steadily rising. However, at the current status of modern medicine, at least in the high-medium income countries, mortality by lack of efficacy of the antibiotic armamentarium in the therapy of infections is a problem, but not a catastrophe. The threat of antibiotic resistance has many other aspects than failures of therapy in the individual patient. Among them, the increase in the frequency of severe and potentially lethal infections, as bacteremia, the population biology alterations of the healthy microbiota, the global acceleration of bacterial evolution by selecting natural genetic tools mediating microbial interactions, and, most importantly, by modifying the equilibrium and composition of environmental microbial communities. All these threats have huge implications for human health as members of a Biosphere entirely rooted in a menaced microbiosphere.
Topics: Anti-Bacterial Agents; Bacteria; Drug Resistance, Bacterial; Drug Resistance, Microbial; Humans; Microbiota
PubMed: 34028624
DOI: 10.1007/s10123-021-00184-y