J.DELANEY 1*, S. RAGUIDEAU 2, C. BORSETTO 1, R.S. JAMES 1, E.R. TRAVIS 1, L. SONG 3, C.QUINCE 2 & E.M.H WELLINGTON 1.
James.Delaney@warwick.ac.uk*
1 School of Life Sciences, University of Warwick, Gibbett Hill Campus, CV4 7AL. 2 Warwick Medical School, University of Warwick, Gibbett Hill Campus, CV4 7AL.
3 School of Chemistry, University of Warwick, Central Campus, CV4 7AL.
The role of the environment in the increase in antibiotic-resistant infections and risk to humans is not well understood. Substantial quantities of antibiotics and antibiotic resistant genes (ARGs) are released from Waste Water Treatment Plants (WWTPs) into river systems.
To better understand the impact of antibiotics in our rivers, this study used microcosm experiments to assess the impact of antibiotics released from WWTPs on bacterial communities in terms of ARG prevalence. Sediment and water samples were collected from a river site downstream of a large WWTP on the River Thames and added to triplicate sets of microcosm tanks in two independent experiments. A sub-lethal dose of the antibiotic sulfamethoxazole (SMX) was added to one triplicate set of tanks and remaining tanks were used as controls. Samples of sediment and water were collected at intervals across a 25-day period.
Using Liquid Chromatography Mass Spectrometry (LC-MS), the concentration of SMX was measured continually over the 25 days. Then molecular methods were used to determine prevalence of the sul1, dfra1 and inti1 antibiotic resistance genes as a result of bacterial exposure to SMX. The sul1 and inti1 genes were found to be significantly more prevalent in the presence of SMX compared to the controls.
This research indicates that sub-clinical SMX can have a significant impact upon the prevalence of ARGs in sediment and water.
Figure 1- How antibiotics and antibiotic resistance genes can accumulate in environmental systems (Qiao et al, 2017)
References:
Qiao, M., Ying, G.G., Singer, A.C., Zhu, Y.G. (2017) Review of antibiotic resistance in China and its environment. Environ Int. 2018;110:160-172. doi:10.1016/j.envint.2017.10.016