12pm – 1.30pm GMT, 22 March 2021 ‐ 1 hour 30 mins
Presentation
These talks are led by professionals in their field and are an opportunity to explore research conducted beyond your institution or organisation. This session is themed around environmental microbiology.
ECS talks are an opportunity for scientists who are beginning their career to showcase their recent work. The project being presented does not have to be complete, but it’s a great way to practice presenting and answering audience questions in a friendly, supportive environment.
Storm surges, flooding, and the encroaching of seawater onto land that could potentially be used as farmland is predicted to increase with changes in our climate. It is, therefore, important to understand the knock-on effect seawater flooding may have on the health of the soil, and its ability to recover functioning. The system chosen was a naturally occurring Saltmarsh-Pasture gradient, incorporating a legacy of differing levels of seawater ingress. We tested the hypotheses that (1) resistance to seawater flooding is a factor of pre-adaptation to the stress, and (2) this adaptation will resolve in different rates of recovery.
This project was designed to simulate the flooding of terrestrial soil and elevations of Saltmarsh systems to monitor 1) changes in environmental parameters (pH, metal concentration, conductivity), 2) microbial functioning (metabolic activity and degradative enzymes), and 3) community composition (16S rRNA gene & ITS amplicon sequencing), over 0,1,96 and 192 hours submersion of soils from differing historical flooding exposure. This equates to 72 microcosms sampled across three timepoints: pre-flooding, post-flooding (immediately), and (14 days) post-recovery
Our data indicated that conductivity and pH levels within the pasture significantly increased with flooding duration, overall metal concentrations grouped dependent on site and concentrations decreased post recovery. Enzyme activity during flooding is similar between all sites, however post-flood pasture site and enzyme activity converges similar to Saltmarsh community activity as flooding treatment increased.
These results suggest that communities previously exposed to seawater flooding have increased resistance and resilience, with the addition of community composition (currently ongoing), we will be able to understand the community dynamics that underpin these data.
This research is important in understanding the impacts of seawater intrusion on potential farmland, potentially reducing community productivity and negatively impacting food security.
In this study 25 cattle farmyard manure samples and 9 fattening calve slurry samples from Belgian farms were investigated on the presence of antibiotic resistant E. coli and 69 antibiotic residues.
Antimicrobial susceptibility testing was performed on preselected (for resistance to cefotaxime, ciprofloxacin, meropenem or colistin) and non-preselected E. coli isolates. In the fattening calve slurry samples, ciprofloxacin- and cefotaxime-resistant E. coli bacteria were both present in 7 of the 9 samples. In each fattening calve slurry sample, at least 8 different antibiotic residues were detected. Doxycycline, oxytetracycline, ciprofloxacin, enrofloxacin, flumequine and lincomycin were detected in all fattening calve slurry samples. Doxycycline and oxytetracycline were found in the highest mean concentrations; 2776 and 4078 µg/kg manure, respectively. Flumequine was found in a concentration of 536 µg/kg manure whereas the other residues were found in mean concentrations <100 µg/kg manure. Sulfadiazine was detected in 8 of the 9 samples in a mean concentration of 10895 µg/kg. In the cattle farmyard manure samples, ciprofloxacin- and cefotaxime-resistant E. coli were found in respectively 7 and 5 of the 25 samples. Antibiotic residues were found in only 4 of the 25 samples. Oxytetracycline was detected twice in a mean concentration of 250 µg/kg. Paromomycin, ciprofloxacin and enrofloxacin were detected in one sample in a concentration <100 µg/kg. Of the non-preselected E. coli isolates, 88% and 23% of the isolates from fattening calve slurry and cattle farmyard manure, respectively, were resistant to at least one of the antibiotics tested. A MDR up to 10 and 7 antibiotics, respectively, was observed.
The occurrence of antibiotic resistant E. coli and antibiotic residues seems to be higher in fattening calve slurry samples than in cattle farmyard manure samples used for agricultural field fertilization.
Antibiotic resistant bacteria and antibiotic residues enter the environment when using animal manure as fertilizer.
The University of Sheffield
Duncan Cameron is Professor of Plant and Soil Biology in the Department of Animal and Plant Sciences at the University of Sheffield where his research group investigates the physiology and chemistry of plant-microbe interactions in the soil in the context of sustainable agriculture and global food security. Duncan is co-director of the University of Sheffield Flagship research institute, the Institute for Sustainable Food and is the University of Sheffield's lead academic for the N8 AgriFood program. Duncan's research is highly interdisciplinary, with collaborative projects linking between science, social science and the arts. He is actively engaged in public engagement, recent projects include the multi-media sci-art collaboration, Gaiamycota, the Sound of Science, and AquaKulture. Duncan actively supports equality, diversity and inclusion at The University of Sheffield as a gay role model.