A paper that was a long time in the making came out last week. Lead author Andy Dickinson (since moved for a PhD in astrobiology in Edinburgh) did a Masters by Research project with Britt Koskella (since moved to Berkeley) and myself. From the Abstract:
Frequent and persistent heavy metal pollution has profound effects on the composition and activity of microbial communities. Heavy metals select for metal resistance but can also co-select for resistance to antibiotics, which is a global health concern. We here document metal concentration, metal resistance and antibiotic resistance along a sediment archive from a pond in the North West of the United Kingdom covering over a century of anthropogenic pollution. We specifically focus on zinc, as it is a ubiquitous and toxic metal contaminant known to co-select for antibiotic resistance, to assess the impact of temporal variation in heavy metal pollution on microbial community diversity and to quantify the selection effects of differential heavy metal exposure on antibiotic resistance. Zinc concentration and bioavailability was found to vary over the core, likely reflecting increased industrialisation around the middle of the 20th century. Zinc concentration had a significant effect on bacterial community composition, as revealed by a positive correlation between the level of zinc tolerance in culturable bacteria and zinc concentration. The proportion of zinc resistant isolates was also positively correlated with resistance to three clinically relevant antibiotics (oxacillin, cefotaxime and trimethoprim). The abundance of the class 1 integron-integrase gene, intI1, marker for anthropogenic pollutants correlated with the prevalence of zinc- and cefotaxime resistance but not with oxacillin and trimethoprim resistance. Our microbial palaeontology approach reveals that metal-contaminated sediments from depths that pre-date the use of antibiotics were enriched in antibiotic resistant bacteria, demonstrating the pervasive effects of metal-antibiotic co-selection in the environment.
Check out the Open Access paper on the Envrionment International website:
Dickinson, A.W., Power, A., Hansen, M.G., Brandt, K.K., Piliposian, G., Appleby, P., O’Neill, P.A., Jones, R.T., Sierocinski, P., Koskella, B. and Vos, M., 2019. Heavy metal pollution and co-selection for antibiotic resistance: a microbial palaeontology approach. Environment international, 132, p.105117.
This was a project in collaboration with Exeter Geographer Dr. Richard Jones who sadly passed away before publication. He was one of the most enthusiastic and collegial researchers I have ever met and is sorely missed by all.
The work followed on from even older student projects supervised by Britt and myself where we are interested in isolating bacteria and their viruses from sediment cores to track their co-evolution through time. In the end, that proved impossible, although that project taught us a lot about the coring approach and greatly helped designing Andy’s project. See this post and this post describing these previous coring adventures.