scholarly journals Signatures of negative frequency dependent selection in colonisation factors and the evolution of a multi-drug resistant lineage of Escherichia coli

2018 ◽  
Author(s):  
Alan McNally ◽  
Teemu Kallonen ◽  
Christopher Connor ◽  
Khalil Abudahab ◽  
David M. Aanensen ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Treatment Options ◽  
Ecological Niches ◽  
Drug Resistant ◽  
Frequency Dependent ◽  
Frequency Dependent Selection ◽  
Public Health Burden ◽  
Increased Risk ◽  
Negative Frequency Dependent Selection ◽  
Tract Infections

AbstractEscherichia coli is a major cause of bloodstream and urinary tract infections globally. The wide dissemination of multi-drug resistant (MDR) strains of extra-intestinal pathogenic E. coli (ExPEC) poses a rapidly increasing public health burden due to narrowed treatment options and increased risk of failure to clear an infection. Here, we present a detailed population genomic analysis of the ExPEC ST131 clone, in which we seek explanations for its success as an emerging pathogenic strain beyond the acquisition of antimicrobial resistance (AMR) genes. We show evidence for evolution towards separate ecological niches for the main clades of ST131 and differential evolution of anaerobic metabolism, key colonisation and virulence factors. We further demonstrate that negative frequency-dependent selection acting across accessory loci is a major mechanism that has shaped the population evolution of this pathogen.

scholarly journals Diversification of Colonization Factors in a Multidrug-Resistant Escherichia coli Lineage Evolving under Negative Frequency-Dependent Selection

mBio ◽  
2019 ◽  
Vol 10 (2) ◽  
Author(s):  
Alan McNally ◽  
Teemu Kallonen ◽  
Christopher Connor ◽  
Khalil Abudahab ◽  
David M. Aanensen ◽  
...  
Keyword(s):  
Public Health ◽  
Escherichia Coli ◽  
Anaerobic Metabolism ◽  
Multidrug Resistant ◽  
Frequency Dependent ◽  
Frequency Dependent Selection ◽  
Content Type ◽  
E Coli ◽  
Negative Frequency Dependent Selection ◽  
Tract Infections

ABSTRACT Escherichia coli is a major cause of bloodstream and urinary tract infections globally. The wide dissemination of multidrug-resistant (MDR) strains of extraintestinal pathogenic E. coli (ExPEC) poses a rapidly increasing public health burden due to narrowed treatment options and increased risk of failure to clear an infection. Here, we present a detailed population genomic analysis of the ExPEC ST131 clone, in which we seek explanations for its success as an emerging pathogenic strain beyond the acquisition of antimicrobial resistance (AMR) genes. We show evidence for evolution toward separate ecological niches for the main clades of ST131 and differential evolution of anaerobic metabolism, key colonization, and virulence factors. We further demonstrate that negative frequency-dependent selection acting across accessory loci is a major mechanism that has shaped the population evolution of this pathogen. IMPORTANCE Infections with multidrug-resistant (MDR) strains of Escherichia coli are a significant global public health concern. To combat these pathogens, we need a deeper understanding of how they evolved from their background populations. By understanding the processes that underpin their emergence, we can design new strategies to limit evolution of new clones and combat existing clones. By combining population genomics with modelling approaches, we show that dominant MDR clones of E. coli are under the influence of negative frequency-dependent selection, preventing them from rising to fixation in a population. Furthermore, we show that this selection acts on genes involved in anaerobic metabolism, suggesting that this key trait, and the ability to colonize human intestinal tracts, is a key step in the evolution of MDR clones of E. coli.

scholarly journals Risk factors for acquisition of multidrug-resistant Escherichia coli and development of community-acquired urinary tract infections

2017 ◽  
Vol 146 (1) ◽  
pp. 46-57 ◽  
Author(s):  
U. V. UKAH ◽  
M. GLASS ◽  
B. AVERY ◽  
D. DAIGNAULT ◽  
M. R. MULVEY ◽  
...  
Keyword(s):  
Risk Factors ◽  
Escherichia Coli ◽  
Urinary Tract ◽  
Antibiotic Use ◽  
Multidrug Resistant ◽  
Health Concern ◽  
Drug Resistant ◽  
E Coli ◽  
Increased Risk ◽  
Tract Infections

SUMMARYWe examined risk factors associated with the intestinal acquisition of antimicrobial-resistant extraintestinal pathogenic Escherichia coli (ExPEC) and development of community-acquired urinary tract infection (UTI) in a case-control study of young women across Canada. A total of 399 women were recruited; 164 women had a UTI caused by E. coli resistant to ⩾1 antimicrobial classes and 98 had a UTI caused by E. coli resistant to ⩾3 antimicrobial classes. After adjustment for age, student health service (region of Canada) and either prior antibiotic use or UTI history, consumption of processed or ground chicken, cooked or raw shellfish, street foods and any organic fruit; as well as, contact with chickens, dogs and pet treats; and travel to Asia, were associated with an increased risk of UTI caused by antimicrobial resistant E. coli. A decreased risk of antimicrobial resistant UTI was associated with consumption of apples, nectarines, peppers, fresh herbs, peanuts and cooked beef. Drug-resistant UTI linked to foodborne and environmental exposures may be a significant public health concern and understanding the risk factors for intestinal acquisition of existing or newly emerging lineages of drug-resistant ExPEC is important for epidemiology, antimicrobial stewardship and prevention efforts.

scholarly journals A geographic cline induced by negative frequency-dependent selection

2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuma Takahashi ◽  
Satoru Morita ◽  
Jin Yoshimura ◽  
Mamoru Watanabe
Keyword(s):  
Frequency Dependent ◽  
Frequency Dependent Selection ◽  
Negative Frequency Dependent Selection

scholarly journals Intruder colour and light environment jointly determine how nesting male stickleback respond to simulated territorial intrusions

2016 ◽  
Vol 12 (8) ◽  
pp. 20160467 ◽  
Author(s):  
Daniel I. Bolnick ◽  
Kimberly Hendrix ◽  
Lyndon Alexander Jordan ◽  
Thor Veen ◽  
Chad D. Brock
Keyword(s):  
Frequency Dependence ◽  
Three Dimensional ◽  
Light Environment ◽  
Depth Gradient ◽  
Frequency Dependent ◽  
Frequency Dependent Selection ◽  
Negative Frequency Dependent Selection ◽  
Colour Signals

Variation in male nuptial colour signals might be maintained by negative frequency-dependent selection. This can occur if males are more aggressive towards rivals with locally common colour phenotypes. To test this hypothesis, we introduced red or melanic three-dimensional printed-model males into the territories of nesting male stickleback from two optically distinct lakes with different coloured residents. Red-throated models were attacked more in the population with red males, while melanic models were attacked more in the melanic male lake. Aggression against red versus melanic models also varied across a depth gradient within each lake, implying that the local light environment also modulated the strength of negative frequency dependence acting on male nuptial colour.

scholarly journals Interplay of Darwinian and frequency-dependent selection in the host-associated microbial population

2005 ◽  
Vol 3 (3) ◽  
pp. 3-11
Author(s):  
Nikolay I Vorobyov ◽  
Nikolay A Provorov
Keyword(s):  
Mathematical Simulation ◽  
Microbial Population ◽  
Genetically Modified ◽  
Ecological Niches ◽  
Soil System ◽  
Selection Pressures ◽  
Frequency Dependent ◽  
Frequency Dependent Selection ◽  
Plant Soil ◽  
Balanced Polymorphism

The method for mathematical simulation is suggested to analyze the balanced polymorphism in rhizobia population generated due to the interplay of Darwinian and frequency-dependent selection. Analysis of the model suggested that this polymorphism is determined not only by the selection pressures but also by the capacities of ecological niches occupied by bacteria in the «plant-soil» system. The model may be used for analyzing the selective processes in various symbiotic systems and for predicting the consequences of releasing of genetically modified plant symbionts into environment.

scholarly journals Negative frequency-dependent selection maintains coexisting genotypes during fluctuating selection

2019 ◽  
Author(s):  
Caroline B. Turner ◽  
Sean W. Buskirk ◽  
Katrina B. Harris ◽  
Vaughn S. Cooper
Keyword(s):  
Evolutionary Dynamics ◽  
Burkholderia Cenocepacia ◽  
Natural Environments ◽  
Fluctuating Selection ◽  
Frequency Dependent ◽  
Frequency Dependent Selection ◽  
Fluctuating Environment ◽  
Fluctuating Environments ◽  
Negative Frequency Dependent Selection ◽  
Selection For

AbstractNatural environments are rarely static; rather selection can fluctuate on time scales ranging from hours to centuries. However, it is unclear how adaptation to fluctuating environments differs from adaptation to constant environments at the genetic level. For bacteria, one key axis of environmental variation is selection for planktonic or biofilm modes of growth. We conducted an evolution experiment with Burkholderia cenocepacia, comparing the evolutionary dynamics of populations evolving under constant selection for either biofilm formation or planktonic growth with populations in which selection fluctuated between the two environments on a weekly basis. Populations evolved in the fluctuating environment shared many of the same genetic targets of selection as those evolved in constant biofilm selection, but were genetically distinct from the constant planktonic populations. In the fluctuating environment, mutations in the biofilm-regulating genes wspA and rpfR rose to high frequency in all replicate populations. A mutation in wspA first rose rapidly and nearly fixed during the initial biofilm phase but was subsequently displaced by a collection of rpfR mutants upon the shift to the planktonic phase. The wspA and rpfR genotypes coexisted via negative frequency-dependent selection around an equilibrium frequency that shifted between the environments. The maintenance of coexisting genotypes in the fluctuating environment was unexpected. Under temporally fluctuating environments coexistence of two genotypes is only predicted under a narrow range of conditions, but the frequency-dependent interactions we observed provide a mechanism that can increase the likelihood of coexistence in fluctuating environments.

scholarly journals Negative frequency dependent selection contributes to the maintenance of a global polymorphism in mitochondrial DNA

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Zorana Kurbalija Novičić ◽  
Ahmed Sayadi ◽  
Mihailo Jelić ◽  
Göran Arnqvist
Keyword(s):  
Mitochondrial Dna ◽  
Genetic Variation ◽  
Life History ◽  
Balancing Selection ◽  
Food Resource ◽  
Ecological Processes ◽  
Central Process ◽  
Frequency Dependent ◽  
Frequency Dependent Selection ◽  
Negative Frequency Dependent Selection

Abstract Background Understanding the forces that maintain diversity across a range of scales is at the very heart of biology. Frequency-dependent processes are generally recognized as the most central process for the maintenance of ecological diversity. The same is, however, not generally true for genetic diversity. Negative frequency dependent selection, where rare genotypes have an advantage, is often regarded as a relatively weak force in maintaining genetic variation in life history traits because recombination disassociates alleles across many genes. Yet, many regions of the genome show low rates of recombination and genetic variation in such regions (i.e., supergenes) may in theory be upheld by frequency dependent selection. Results We studied what is essentially a ubiquitous life history supergene (i.e., mitochondrial DNA) in the fruit fly Drosophila subobscura, showing sympatric polymorphism with two main mtDNA genotypes co-occurring in populations world-wide. Using an experimental evolution approach involving manipulations of genotype starting frequencies, we show that negative frequency dependent selection indeed acts to maintain genetic variation in this region. Moreover, the strength of selection was affected by food resource conditions. Conclusions Our work provides novel experimental support for the view that balancing selection through negative frequency dependency acts to maintain genetic variation in life history genes. We suggest that the emergence of negative frequency dependent selection on mtDNA is symptomatic of the fundamental link between ecological processes related to resource use and the maintenance of genetic variation.

Sign in / Sign up

Export Citation Format

Share Document