Search arXivSearch

arXiv · 2402.04939

A Combined Experimental and Mathematical Study of The Evolution of Microbial Community Composed of Interacting Staphylococcus Strains

Abstract

The emergence of the phenomenon known as ABR (anti-bacterial resistance), is the result of the gradual decrease in the efficacy of antibiotics and the increase in the cost of producing new antibiotics. Hence, alternative solutions to prevent the spread of the pathogenic species are required. Here we present a combined experimental and mathematical study of the evolution of microbial communities. The aim was to investigate the role of skin bacteria invasion and competition in limiting pathogenic species growth and colonisation, and to determine and reveal factors and conditions that alter and influence the dynamics of interactions between species. The focus in this study was Staphylococcus aureus as it is considered a major human pathogen that shows colonisation traits distinct from the more abundant skin antimicrobial-secreting residents, S. epidermidis and S. hominis. The method adopted when conducting this study was based on two approaches: experimental and mathematical. The novelty and significance of this study lies in the fact that, unlike that found in a previous studies the manipulation of spatial structures, the level of toxicity, and initial frequencies did not prevent the emergence of resistance in the evolved S. aureus populations. The evolved S. aureus populations were able to dominate their opponents regardless of the environmental conditions. However, it was found that the level of toxicity and environmental regulations made it harder for evolved S. aureus populations to recover.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Nouf Alghamdi, Mal Horsburgh, Bakhtier Vasiev. 2024-02-07. A Combined Experimental and Mathematical Study of The Evolution of Microbial Community Composed of Interacting Staphylococcus Strains. https://arxiv.org/abs/2402.04939

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Phase transitions in microbial lineage trees

Microbial populations exhibit high cell-to-cell variability, which fundamentally shapes population behavior. A striking consequence is the existence of phase transitions, where small genetic or environmental changes trigger abrupt shifts in population dynamics. While biological phase transitions have often been proposed, connecting observed behavior to the underlying physics has remained challenging. We combine population genetics with statistical physics to show how phase transitions arise naturally in microbial populations. We highlight the existence of a first-order transition in a model of bacterial plasmid engineering and find a strict lower bound on the number of plasmids that can be stably maintained in a population.

q-bio.PE

Phylogenetic Inference and the Stickiness of Fréchet Means, via Precise Asymptotics of an Embedded Random Walk

A well-known phenomenon in statistical analyses of populations of phylogenetic trees in the Billera-Holmes-Vogtmann space is that the topology of the Fréchet mean tree can contain multifurcations (i.e., internal nodes with more than two children), which raises the practical question of whether this reflects a population-level branching structure (hard polytomy) or merely sampling variability in the data (soft polytomy). This is an instance of the more general phenomenon of "stickiness" in non-Euclidean statistics, whereby the sample Fréchet mean in certain non-positively curved stratified spaces becomes permanently trapped in a lower-dimensional stratum. In this work, we identify a particular multidimensional random walk embedded within the Fréchet mean process, and we show that the time at which stickiness occurs is determined by the largest last-passage time above zero of the coordinates of this random walk. Using this representation, we develop a fully nonparametric procedure for estimating the probability that trifurcations in a sample Fréchet mean tree will bifurcate at some future time if more observations are collected. Lastly, we apply our methodology to a problem in phylogenetics where we consider whether an observed trifurcation in the species tree of primates, glires, and tree shrews is genuinely trifurcated at the population level.

q-bio.PE

Coexistence coalitions in propagule disperser quasi-communities

Many natural ecosystems harbor large numbers of coexisting species competing for far fewer distinct resources, in apparent defiance of the competitive exclusion principle. Various mechanisms have been proposed to explain this apparent paradox, often pertaining to organisms with a two-stage sessile--propagule life cycle. Here we develop a stochastic model class for such propagule disperser communities that combines competition--colonization trade-offs, spatial heterogeneity, demographic stochasticity, as well as inherited trait variation, and recover several classical models as special or limiting cases. Using bifurcation analysis, we classify equilibrium coalitions near the extinction threshold and give sufficient conditions for their realization by macroscopic equilibria away from the threshold, bypassing the costly numerical computation of the actual equilibrium states. Illustrative examples examine the resulting trait distributions and coalition patterns, demonstrating the interactive effects of different coexistence mechanisms.

q-bio.PE