# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 9580 | 0 | 0.9978 | Antibiotic resistance in bacterial communities. Bacteria are single-celled organisms, but the survival of microbial communities relies on complex dynamics at the molecular, cellular, and ecosystem scales. Antibiotic resistance, in particular, is not just a property of individual bacteria or even single-strain populations, but depends heavily on the community context. Collective community dynamics can lead to counterintuitive eco-evolutionary effects like survival of less resistant bacterial populations, slowing of resistance evolution, or population collapse, yet these surprising behaviors are often captured by simple mathematical models. In this review, we highlight recent progress - in many cases, advances driven by elegant combinations of quantitative experiments and theoretical models - in understanding how interactions between bacteria and with the environment affect antibiotic resistance, from single-species populations to multispecies communities embedded in an ecosystem. | 2023 | 37054512 |
| 9371 | 1 | 0.9977 | Coevolutionary history of predation constrains the evolvability of antibiotic resistance in prey bacteria. Understanding how the historical contingency of biotic interactions shapes the evolvability of bacterial populations is imperative for the predictability of the eco-evolutionary dynamics of microbial communities. While microbial predators like Myxococcus xanthus influence the frequency of antibiotic-resistant bacteria in nature, the effect of adaptation to the presence of predators on the evolvability of prey bacteria to future stressors is unclear. Hence, to understand the influence of the coevolutionary history of predation on the evolvability of antibiotic resistance, we propagated variants of E. coli, pre-adapted to distinct biotic and abiotic conditions, in gradually increasing concentrations of antibiotics. We show that pre-adaptation to predators limits the evolution of a high degree of antibiotic resistance. Moreover, lower degree of resistance in the evolved strains also incurs reduced fitness costs while preserving their ancestral ability to resist predation. Together, we demonstrate that the history of biotic interactions can strongly influence the evolvability of bacteria. | 2025 | 40461734 |
| 9391 | 2 | 0.9976 | Bacteria-phage (co)evolution is constrained in a synthetic community across multiple bacteria-phage pairs. Bacteriophages can be important drivers of bacterial densities and, therefore, microbial community composition and function. These ecological interactions are likely to be greatly affected by evolutionary dynamics because bacteria can rapidly evolve resistance to phage, while phage can reciprocally evolve to increase infectivity. Most studies to date have explored eco-evolutionary dynamics using isolated pairs of bacteria-phage, but in nature, multiple bacteria and phages coexist and (co)evolve simultaneously. How coevolution plays out in this context is poorly understood. Here, we examine how three coexisting soil bacteria (Ochrobactrum sp., Pseudomonas sp. and Variovorax sp.) interact and evolve with three species-specific bacteriophages over 8 weeks of experimental evolution, both as host-parasite pairs in isolation and as a mixed community. Across all species, phage resistance evolution was inhibited in polyculture, with the most pronounced effect on Ochrobactrum. Between bacteria-phage pairs, there were also substantial differences in the effect of phage on host densities and evolutionary dynamics, including whether pairs coevolved. Our results also indicate bacteria have a relative advantage over phage, with high rates of phage extinction and/or lower densities in polyculture. These contrasts emphasize the difficulty in generalizing findings from monoculture to polyculture and between model bacteria-phage pairs to wider systems. Future studies should consider how multiple bacteria and phage pairs interact simultaneously to better understand how coevolutionary dynamics happen in natural communities. | 2025 | 40536890 |
| 9388 | 3 | 0.9976 | Suboptimal environmental conditions prolong phage epidemics in bacterial populations. Infections by filamentous phages, which are usually nonlethal to the bacterial cells, influence bacterial fitness in various ways. While phage-encoded accessory genes, for example virulence genes, can be highly beneficial, the production of viral particles is energetically costly and often reduces bacterial growth. Consequently, if costs outweigh benefits, bacteria evolve resistance, which can shorten phage epidemics. Abiotic conditions are known to influence the net-fitness effect for infected bacteria. Their impact on the dynamics and trajectories of host resistance evolution, however, remains yet unknown. To address this, we experimentally evolved the bacterium Vibrio alginolyticus in the presence of a filamentous phage at three different salinity levels, that is (1) ambient, (2) 50% reduction and (3) fluctuations between reduced and ambient. In all three salinities, bacteria rapidly acquired resistance through super infection exclusion (SIE), whereby phage-infected cells acquired immunity at the cost of reduced growth. Over time, SIE was gradually replaced by evolutionary fitter surface receptor mutants (SRM). This replacement was significantly faster at ambient and fluctuating conditions compared with the low saline environment. Our experimentally parameterized mathematical model explains that suboptimal environmental conditions, in which bacterial growth is slower, slow down phage resistance evolution ultimately prolonging phage epidemics. Our results may explain the high prevalence of filamentous phages in natural environments where bacteria are frequently exposed to suboptimal conditions and constantly shifting selections regimes. Thus, our future ocean may favour the emergence of phage-born pathogenic bacteria and impose a greater risk for disease outbreaks, impacting not only marine animals but also humans. | 2024 | 37337348 |
| 9366 | 4 | 0.9975 | Impact of bacterial mutation rate on coevolutionary dynamics between bacteria and phages. Mutator bacteria are frequently found in natural populations of bacteria and although coevolution with parasitic viruses (phages) is thought to be one reason for their persistence, it remains unclear how the presence of mutators affects coevolutionary dynamics. We hypothesized that phages must themselves adapt more rapidly or go extinct, in the face of rapidly evolving mutator bacteria. We compared the coevolutionary dynamics of wild-type Pseudomonas fluorescens SBW25 with a lytic phage to the dynamics of an isogenic mutator of P. fluorescens SBW25 together with the same phage. At the beginning of the experiment both wild-type bacteria and mutator bacteria coevolved with phages. However, mutators rapidly evolved higher levels of sympatric resistance to phages. The phages were unable to "keep-up" with the mutator bacteria, and these rates of coevolution declined to less than the rates of coevolution between the phages and wild-type bacteria. By the end of the experiment, the sympatric resistance of the mutator bacteria was not significantly different to the sympatric resistance of the wild-type bacteria. This suggests that the importance of mutators in the coevolutionary interactions with a particular phage population is likely to be short-lived. More generally, the results demonstrate that coevolving enemies may escape from Red-Queen dynamics. | 2010 | 20497216 |
| 9389 | 5 | 0.9975 | Individual bacteria in structured environments rely on phenotypic resistance to phage. Bacteriophages represent an avenue to overcome the current antibiotic resistance crisis, but evolution of genetic resistance to phages remains a concern. In vitro, bacteria evolve genetic resistance, preventing phage adsorption or degrading phage DNA. In natural environments, evolved resistance is lower possibly because the spatial heterogeneity within biofilms, microcolonies, or wall populations favours phenotypic survival to lytic phages. However, it is also possible that the persistence of genetically sensitive bacteria is due to less efficient phage amplification in natural environments, the existence of refuges where bacteria can hide, and a reduced spread of resistant genotypes. Here, we monitor the interactions between individual planktonic bacteria in isolation in ephemeral refuges and bacteriophage by tracking the survival of individual cells. We find that in these transient spatial refuges, phenotypic resistance due to reduced expression of the phage receptor is a key determinant of bacterial survival. This survival strategy is in contrast with the emergence of genetic resistance in the absence of ephemeral refuges in well-mixed environments. Predictions generated via a mathematical modelling framework to track bacterial response to phages reveal that the presence of spatial refuges leads to fundamentally different population dynamics that should be considered in order to predict and manipulate the evolutionary and ecological dynamics of bacteria-phage interactions in naturally structured environments. | 2021 | 34637438 |
| 9376 | 6 | 0.9974 | Historical Contingency Drives Compensatory Evolution and Rare Reversal of Phage Resistance. Bacteria and lytic viruses (phages) engage in highly dynamic coevolutionary interactions over time, yet we have little idea of how transient selection by phages might shape the future evolutionary trajectories of their host populations. To explore this question, we generated genetically diverse phage-resistant mutants of the bacterium Pseudomonas syringae. We subjected the panel of mutants to prolonged experimental evolution in the absence of phages. Some populations re-evolved phage sensitivity, whereas others acquired compensatory mutations that reduced the costs of resistance without altering resistance levels. To ask whether these outcomes were driven by the initial genetic mechanisms of resistance, we next evolved independent replicates of each individual mutant in the absence of phages. We found a strong signature of historical contingency: some mutations were highly reversible across replicate populations, whereas others were highly entrenched. Through whole-genome sequencing of bacteria over time, we also found that populations with the same resistance gene acquired more parallel sets of mutations than populations with different resistance genes, suggesting that compensatory adaptation is also contingent on how resistance initially evolved. Our study identifies an evolutionary ratchet in bacteria-phage coevolution and may explain previous observations that resistance persists over time in some bacterial populations but is lost in others. We add to a growing body of work describing the key role of phages in the ecological and evolutionary dynamics of their host communities. Beyond this specific trait, our study provides a new insight into the genetic architecture of historical contingency, a crucial component of interpreting and predicting evolution. | 2022 | 35994371 |
| 9581 | 7 | 0.9974 | Lateral gene transfer, bacterial genome evolution, and the Anthropocene. Lateral gene transfer (LGT) has significantly influenced bacterial evolution since the origins of life. It helped bacteria generate flexible, mosaic genomes and enables individual cells to rapidly acquire adaptive phenotypes. In turn, this allowed bacteria to mount strong defenses against human attempts to control their growth. The widespread dissemination of genes conferring resistance to antimicrobial agents has precipitated a crisis for modern medicine. Our actions can promote increased rates of LGT and also provide selective forces to fix such events in bacterial populations. For instance, the use of selective agents induces the bacterial SOS response, which stimulates LGT. We create hotspots for lateral transfer, such as wastewater systems, hospitals, and animal production facilities. Conduits of gene transfer between humans and animals ensure rapid dissemination of recent transfer events, as does modern transport and globalization. As resistance to antibacterial compounds becomes universal, there is likely to be increasing selection pressure for phenotypes with adverse consequences for human welfare, such as enhanced virulence, pathogenicity, and transmission. Improved understanding of the ecology of LGT could help us devise strategies to control this fundamental evolutionary process. | 2017 | 27706829 |
| 6646 | 8 | 0.9974 | Food animals and antimicrobials: impacts on human health. Antimicrobials are valuable therapeutics whose efficacy is seriously compromised by the emergence and spread of antimicrobial resistance. The provision of antibiotics to food animals encompasses a wide variety of nontherapeutic purposes that include growth promotion. The concern over resistance emergence and spread to people by nontherapeutic use of antimicrobials has led to conflicted practices and opinions. Considerable evidence supported the removal of nontherapeutic antimicrobials (NTAs) in Europe, based on the "precautionary principle." Still, concrete scientific evidence of the favorable versus unfavorable consequences of NTAs is not clear to all stakeholders. Substantial data show elevated antibiotic resistance in bacteria associated with animals fed NTAs and their food products. This resistance spreads to other animals and humans-directly by contact and indirectly via the food chain, water, air, and manured and sludge-fertilized soils. Modern genetic techniques are making advances in deciphering the ecological impact of NTAs, but modeling efforts are thwarted by deficits in key knowledge of microbial and antibiotic loads at each stage of the transmission chain. Still, the substantial and expanding volume of evidence reporting animal-to-human spread of resistant bacteria, including that arising from use of NTAs, supports eliminating NTA use in order to reduce the growing environmental load of resistance genes. | 2011 | 21976606 |
| 9390 | 9 | 0.9974 | Parasite diversity drives rapid host dynamics and evolution of resistance in a bacteria-phage system. Host-parasite evolutionary interactions are typically considered in a pairwise species framework. However, natural infections frequently involve multiple parasites. Altering parasite diversity alters ecological and evolutionary dynamics as parasites compete and hosts resist multiple infection. We investigated the effects of parasite diversity on host-parasite population dynamics and evolution using the pathogen Pseudomonas aeruginosa and five lytic bacteriophage parasites. To manipulate parasite diversity, bacterial populations were exposed for 24 hours to either phage monocultures or diverse communities containing up to five phages. Phage communities suppressed host populations more rapidly but also showed reduced phage density, likely due to interphage competition. The evolution of resistance allowed rapid bacterial recovery that was greater in magnitude with increases in phage diversity. We observed no difference in the extent of resistance with increased parasite diversity, but there was a profound impact on the specificity of resistance; specialized resistance evolved to monocultures through mutations in a diverse set of genes. In summary, we demonstrate that parasite diversity has rapid effects on host-parasite population dynamics and evolution by selecting for different resistance mutations and affecting the magnitude of bacterial suppression and recovery. Finally, we discuss the implications of phage diversity for their use as biological control agents. | 2016 | 27005577 |
| 9382 | 10 | 0.9974 | The evolution of mutator genes in bacterial populations: the roles of environmental change and timing. Recent studies have found high frequencies of bacteria with increased genomic rates of mutation in both clinical and laboratory populations. These observations may seem surprising in light of earlier experimental and theoretical studies. Mutator genes (genes that elevate the genomic mutation rate) are likely to induce deleterious mutations and thus suffer an indirect selective disadvantage; at the same time, bacteria carrying them can increase in frequency only by generating beneficial mutations at other loci. When clones carrying mutator genes are rare, however, these beneficial mutations are far more likely to arise in members of the much larger nonmutator population. How then can mutators become prevalent? To address this question, we develop a model of the population dynamics of bacteria confronted with ever-changing environments. Using analytical and simulation procedures, we explore the process by which initially rare mutator alleles can rise in frequency. We demonstrate that subsequent to a shift in environmental conditions, there will be relatively long periods of time during which the mutator subpopulation can produce a beneficial mutation before the ancestral subpopulations are eliminated. If the beneficial mutation arises early enough, the overall frequency of mutators will climb to a point higher than when the process began. The probability of producing a subsequent beneficial mutation will then also increase. In this manner, mutators can increase in frequency over successive selective sweeps. We discuss the implications and predictions of these theoretical results in relation to antibiotic resistance and the evolution of mutation rates. | 2003 | 12871898 |
| 6449 | 11 | 0.9973 | Microbial regulation of natural antibiotic resistance: Understanding the protist-bacteria interactions for evolution of soil resistome. The emergence, evolution and spread of antibiotic resistance genes (ARGs) in the environment represent a global threat to human health. Our knowledge of antibiotic resistance in human-impacted ecosystems is rapidly growing with antibiotic use, organic fertilization and wastewater irrigation identified as key selection pressures. However, the importance of biological interactions, especially predation and competition, as a potential driver of antibiotic resistance in the natural environment with limited anthropogenic disturbance remains largely overlooked. Stress-affected bacteria develop resistance to maximize competition and survival, and similarly bacteria may develop resistance to fight stress under the predation pressure of protists, an essential component of the soil microbiome. In this article, we summarized the major findings for the prevalence of natural ARGs on our planet and discussed the potential selection pressures driving the evolution and development of antibiotic resistance in natural settings. This is the first article that reviewed the potential links between protists and the antibiotic resistance of bacteria, and highlighted the importance of predation by protists as a crucial selection pressure of antibiotic resistance in the absence of anthropogenic disturbance. We conclude that an improved ecological understanding of the protists-bacteria interactions and other biological relationships would greatly expand our ability to predict and mitigate the environmental antibiotic resistance under the context of global change. | 2020 | 31818598 |
| 9385 | 12 | 0.9973 | A generalised model for generalised transduction: the importance of co-evolution and stochasticity in phage mediated antimicrobial resistance transfer. Antimicrobial resistance is a major global challenge. Of particular concern are mobilizable elements that can transfer resistance genes between bacteria, leading to pathogens with new combinations of resistance. To date, mathematical models have largely focussed on transfer of resistance by plasmids, with fewer studies on transfer by bacteriophages. We aim to understand how best to model transfer of resistance by transduction by lytic phages. We show that models of lytic bacteriophage infection with empirically derived realistic phage parameters lead to low numbers of bacteria, which, in low population or localised environments, lead to extinction of bacteria and phage. Models that include antagonistic co-evolution of phage and bacteria produce more realistic results. Furthermore, because of these low numbers, stochastic dynamics are shown to be important, especially to spread of resistance. When resistance is introduced, resistance can sometimes be fixed, and at other times die out, with the probability of each outcome sensitive to bacterial and phage parameters. Specifically, that outcome most strongly depends on the baseline death rate of bacteria, with phage-mediated spread favoured in benign environments with low mortality over more hostile environments. We conclude that larger-scale models should consider spatial compartmentalisation and heterogeneous microenviroments, while encompassing stochasticity and co-evolution. | 2020 | 32490523 |
| 9534 | 13 | 0.9973 | Defining the Benefits of Antibiotic Resistance in Commensals and the Scope for Resistance Optimization. Antibiotic resistance is a major medical and public health challenge, characterized by global increases in the prevalence of resistant strains. The conventional view is that all antibiotic resistance is problematic, even when not in pathogens. Resistance in commensal bacteria poses risks, as resistant organisms can provide a reservoir of resistance genes that can be horizontally transferred to pathogens or may themselves cause opportunistic infections in the future. While these risks are real, we propose that commensal resistance can also generate benefits during antibiotic treatment of human infection, by promoting continued ecological suppression of pathogens. To define and illustrate this alternative conceptual perspective, we use a two-species mathematical model to identify the necessary and sufficient ecological conditions for beneficial resistance. We show that the benefits are limited to species (or strain) interactions where commensals suppress pathogen growth and are maximized when commensals compete with, rather than prey on or otherwise exploit pathogens. By identifying benefits of commensal resistance, we propose that rather than strictly minimizing all resistance, resistance management may be better viewed as an optimization problem. We discuss implications in two applied contexts: bystander (nontarget) selection within commensal microbiomes and pathogen treatment given polymicrobial infections. IMPORTANCE Antibiotic resistance is commonly viewed as universally costly, regardless of which bacterial cells express resistance. Here, we derive an opposing logic, where resistance in commensal bacteria can lead to reductions in pathogen density and improved outcomes on both the patient and public health scales. We use a mathematical model of commensal-pathogen interactions to define the necessary and sufficient conditions for beneficial resistance, highlighting the importance of reciprocal ecological inhibition to maximize the benefits of resistance. More broadly, we argue that determining the benefits as well as the costs of resistances in human microbiomes can transform resistance management from a minimization to an optimization problem. We discuss applied contexts and close with a review of key resistance optimization dimensions, including the magnitude, spectrum, and mechanism of resistance. | 2023 | 36475750 |
| 9583 | 14 | 0.9973 | Bacteriophages presence in nature and their role in the natural selection of bacterial populations. Phages are the obligate parasite of bacteria and have complex interactions with their hosts. Phages can live in, modify, and shape bacterial communities by bringing about changes in their abundance, diversity, physiology, and virulence. In addition, phages mediate lateral gene transfer, modify host metabolism and reallocate bacterially-derived biochemical compounds through cell lysis, thus playing an important role in ecosystem. Phages coexist and coevolve with bacteria and have developed several antidefense mechanisms in response to bacterial defense strategies against them. Phages owe their existence to their bacterial hosts, therefore they bring about alterations in their host genomes by transferring resistance genes and genes encoding toxins in order to improve the fitness of the hosts. Application of phages in biotechnology, environment, agriculture and medicines demands a deep insight into the myriad of phage-bacteria interactions. However, to understand their complex interactions, we need to know how unique phages are to their bacterial hosts and how they exert a selective pressure on the microbial communities in nature. Consequently, the present review focuses on phage biology with respect to natural selection of bacterial populations. | 2020 | 33170167 |
| 9174 | 15 | 0.9973 | Developing Phage Therapy That Overcomes the Evolution of Bacterial Resistance. The global rise of antibiotic resistance in bacterial pathogens and the waning efficacy of antibiotics urge consideration of alternative antimicrobial strategies. Phage therapy is a classic approach where bacteriophages (bacteria-specific viruses) are used against bacterial infections, with many recent successes in personalized medicine treatment of intractable infections. However, a perpetual challenge for developing generalized phage therapy is the expectation that viruses will exert selection for target bacteria to deploy defenses against virus attack, causing evolution of phage resistance during patient treatment. Here we review the two main complementary strategies for mitigating bacterial resistance in phage therapy: minimizing the ability for bacterial populations to evolve phage resistance and driving (steering) evolution of phage-resistant bacteria toward clinically favorable outcomes. We discuss future research directions that might further address the phage-resistance problem, to foster widespread development and deployment of therapeutic phage strategies that outsmart evolved bacterial resistance in clinical settings. | 2023 | 37268007 |
| 9701 | 16 | 0.9972 | Environmental factors influencing the development and spread of antibiotic resistance. Antibiotic resistance and its wider implications present us with a growing healthcare crisis. Recent research points to the environment as an important component for the transmission of resistant bacteria and in the emergence of resistant pathogens. However, a deeper understanding of the evolutionary and ecological processes that lead to clinical appearance of resistance genes is still lacking, as is knowledge of environmental dispersal barriers. This calls for better models of how resistance genes evolve, are mobilized, transferred and disseminated in the environment. Here, we attempt to define the ecological and evolutionary environmental factors that contribute to resistance development and transmission. Although mobilization of resistance genes likely occurs continuously, the great majority of such genetic events do not lead to the establishment of novel resistance factors in bacterial populations, unless there is a selection pressure for maintaining them or their fitness costs are negligible. To enable preventative measures it is therefore critical to investigate under what conditions and to what extent environmental selection for resistance takes place. In addition, understanding dispersal barriers is not only key to evaluate risks, but also to prevent resistant pathogens, as well as novel resistance genes, from reaching humans. | 2018 | 29069382 |
| 6452 | 17 | 0.9972 | Megacities as sources for pathogenic bacteria in rivers and their fate downstream. Poor sanitation, poor treatments of waste water, as well as catastrophic floods introduce pathogenic bacteria into rivers, infecting and killing many people. The goal of clean water for everyone has to be achieved with a still growing human population and their rapid concentration in large cities, often megacities. How long introduced pathogens survive in rivers and what their niches are remain poorly known but essential to control water-borne diseases in megacities. Biofilms are often niches for various pathogens because they possess high resistances against environmental stress. They also facilitate gene transfers of antibiotic resistance genes which become an increasing health problem. Beside biofilms, amoebae are carriers of pathogenic bacteria and niches for their survival. An overview about our current understanding of the fate and niches of pathogens in rivers, the multitude of microbial community interactions, and the impact of severe flooding, a prerequisite to control pathogens in polluted rivers, is given. | 2011 | 20885968 |
| 9578 | 18 | 0.9972 | Type III secretion systems in symbiotic adaptation of pathogenic and non-pathogenic bacteria. The emergence of multi-drug resistance and bacteria with increased virulence is a familiar refrain to the contemporary microbiologist. Although intense research over the past decade has ascribed much molecular detail to these processes, more esoteric questions remain: for example, why are some bacteria evolving increased virulence towards humans, what are the genes underpinning this virulence potential and what are the selective pressures that favor these traits? A holistic approach that considers the organismal biology of bacteria with their diverse hosts seems appropriate to begin to tackle such issues. As it happens, the type III secretion system is turning out to be a central player in the adaptation of both parasites and mutualists to diverse hosts. With this in mind, human interventions in agriculture, animal husbandry and even drug discovery that could influence the selection of bacteria with improved type III secretion system function should be critically appraised. | 2009 | 19217298 |
| 9190 | 19 | 0.9972 | Phage-based biocontrol strategies and their application in agriculture and aquaculture. Meeting global food demands for a growing human population with finite natural resources is a major challenge. Aquaculture and agriculture are critical to satisfy food requirements, yet suffer significant losses from bacterial diseases. Therefore, there is an urgent need to develop novel antimicrobial strategies, which is heightened by increasing antibiotic resistance. Bacteriophages (phages) are viruses that specifically infect bacteria, and phage-derived therapies are promising treatments in the fight against bacterial diseases. Here, we describe multiple ways that phages and phage-based technologies can be used as antimicrobials. Antimicrobial activity can be achieved through lysis of targeted bacteria by virulent phages or lytic enzymes. Alternatively, phages can be engineered for the delivery of lethal genes and other cargoes to kill bacteria and to manipulate the bacterial response to conventional antibiotics. We also briefly highlight research exploring phages as potential biocontrol agents with examples from agriculture and aquaculture. | 2018 | 30514766 |