Project background
Soil is one of the largest and most diverse habitats on Earth and it is vital for ecosystems and food production, among other ecosystem services. Soil microorganisms constitute a reservoir of antimicrobial resistance genes (ARGs) available for exchange with clinical pathogens, harbouring as much as 30% of all known ARGs in sequence databases1. ARGs have been found in soils across diverse ecosystems, including remote areas such as the Arctic.
There is emerging evidence from terrestrial ecosystems that antibiotics and warming independently contribute to increased atmospheric greenhouse gas concentrations. Moreover, we also found that microbial interactions shape the temporal dynamics of AMR in the Arctic. We have recently studied whether, how, and why antimicrobial resistance (AMR) varies with soil age in recently deglaciated pioneer and developing Arctic soils using a space-for-time chronosequence approach. We observed that antimicrobial resistance increases over time, and its temporal spread is dependent on competitive and facilitative interactions among microbes for nutrients2.
This proposal aims to investigate whether warming interacts and emerges as a threat to AMR spread through alterations in ARG abundance and soil microbial communities. We hypothesise that warmer soils in the Arctic will exhibit higher levels of AMR.
In this project, you will isolate antibiotic-resistant bacteria from deglaciated Arctic soils and determine their AMR potential. You will also identify those isolates through whole-genome sequencing and use in-silico programs3 to identify potential antibiotic-resistant genes, ultimately contributing to a better understanding of the environmental factors driving this global health concern.
Methodology
Soil sampling. We will sample soils from warmed and control plots from an ongoing 10-year open-chamber warming experiment at Kongsfjordneset, Svalbard, at the westernmost extent of the Brøgger Peninsula.
Community level. You will incubate soils collected from the warming experiments in the presence of antibiotics (Tetracycline, ampicillin, meropenem, gentamicin, and ciprofloxacin) at in situ temperatures. These antibiotics were successfully used in our previous study2, which encompass different antibiotic classes and are frequently used in human and veterinary medicine. To control for the stress effect of remnant antibiotics, microbes will be removed from soil by Nycodenz extraction, washed (e.g. with saline), and added to fresh soil that has not received antibiotics. You will monitor the abundance of AMR genes against the comprehensive antibiotic resistance database and characterise the microbial community through 16S rRNA amplicon sequencing.
Species level: multidrug-resistant and sensitive bacterial strains will be isolated using minimal media with different carbon/energy sources either with or without antibiotic selection. We aim to obtain 20 to 50 strains, each of relatively high and low antibiotic-sensitivity strains. You will perform whole genome sequencing for their identification and to characterise ARGs as described above.
This work is a collaboration between Marcela Hernández at UEA, Marc Dumont (University of Southampton, UK), and James Bradley (MIO, Marseille, France). Online meetings will be held throughout the duration of this placement.
References.
[1] Nesme, J. & Simonet, P. (2015) Environ Microbiol. 17:913-930. https://doi.org/10.1111/1462-2920.12631
[2] Roy et al., 2025. BMC Microbiol. 25:50. https://doi.org/10.1186/s12866-025-03745-7
[3] Dawson et al., 2025. Environ Microbiome 20:12. https://doi.org/10.1186/s40793-025-00672-y
