Droplet-Based Technology for Studying the Phenotypic Effect of Microplastics on Antimicrobial Resistance †
Laboratory of Microfluidics, Department of Chemistry and Biotechnology, School of Science, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia
*
Author to whom correspondence should be addressed.
†
Presented at the International Conference EcoBalt 2023 “Chemicals & Environment”, Tallinn, Estonia, 9–11 October 2023.
Proceedings 2023, 92(1), 41; https://doi.org/10.3390/proceedings2023092041
Published: 24 November 2023
(This article belongs to the Proceedings of International Conference EcoBalt 2023 "Chemicals & Environment")
Plastic pollution is a global emergency [1,2]. One key problem is that microplastics (MPs) (1 µm–5 mm) [3] and nanoplastics (NPs) (≤1 µm) [4] enhance the already severe threat of antimicrobial resistance (AMR) by providing a micro-environment termed the “plastisphere” for bacteria to form biofilms [5,6]. However, exact knowledge of the severity of the plastisphere and its impact on AMR is currently still scarce [7]. Here, we show how droplet-based technology can be used to study the potential phenotypic effect of MPs on AMR. For this we used (i) polydisperse water-in-oil droplets generated via vortexing, (ii) GFB-labelled Escherichia coli JEK 1036 as our study object, (iii) cefotaxime as the test antibiotic, and (iv) 10 µm carboxylated polystyrene microspheres (PS). In parallel, we encapsulated single cells of E. coli into droplets with different concentrations of cefotaxime and with or without PS. After overnight incubation at 37 °C, we imaged droplets as a monolayer via confocal microscopy and analyzed droplets via Software Ilastik [8], CellProfilerTM [9] and EasyFlow [10]. Our results show that E. coli’s minimal inhibitory concentration (MIC) shifts slightly towards a higher cefotaxime concentration when PS is present in droplets. Image analysis of E. coli growth patterns in individual droplets illustrates that E. coli tends to clump together in droplets with PS, versus exhibiting an evenly distributed growth pattern in droplets without PS. In conclusion, we see that PS in droplets might enhance the MIC of E. coli resistance against cefotaxime. This possible enhanced resistance may be related to the observed tendency for clumping (indication of biofilm formation) of E. coli when PS is present. Droplet-based technology is thus a suitable tool for studying the phenotypic effect of MPs on AMR. Further experiments with different antibiotics and MP types and sizes will shed more light on the interesting and worrying tendency of MPs to potentially enhance AMR that was found in this study.
Author Contributions
Conceptualization, S.B. and O.S.; methodology, S.B., F.L.S. and P.P.; software, S.B. and I.S.; validation, S.B. and F.L.S.; formal analysis, S.B., F.L.S. and O.S.; investigation, S.B. and O.S.; resources, O.S.; data curation, S.B. and I.S.; writing—original draft preparation, S.B.; writing—review and editing, S.B. and O.S.; visualization, S.B., F.L.S. and I.S.; supervision, S.B. and O.S.; project administration, O.S.; funding acquisition, S.B. and O.S. All authors have read and agreed to the published version of the manuscript.
Funding
The project was partially funded by Tallinn University of Technology Development Program 2016–2022, project no. 2014–2020.4.01.16.0032; Tallinn University of Technology, grant no. GFLKSB22; Estonian Research Council, grant no. PRG620. The conference participation was funded by COST Action: CA20101 (PRIORITY).
Institutional Review Board Statement
Not applicable.
Informed Consent Statement
Not applicable.
Data Availability Statement
The data presented in this study are available upon request from the corresponding author.
Acknowledgments
We would like to thank Margit Heinlaan, National Institute of Chemical Physics and Biophysics, Tallinn, for kindly providing us with carboxylated polystyrene microspheres used in this work. We would also like to thank Piotr Garstecki at the Institute of Physical Chemistry, Polish Academy of Sciences, Poland, for the kind provision of surfactant and microfluidic chip mold used in laboratory.
Conflicts of Interest
The authors declare no conflict of interest.
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MDPI and ACS Style
Bartkova, S.; Sulp, F.L.; Sanka, I.; Pata, P.; Scheler, O. Droplet-Based Technology for Studying the Phenotypic Effect of Microplastics on Antimicrobial Resistance. Proceedings 2023, 92, 41. https://doi.org/10.3390/proceedings2023092041
AMA Style
Bartkova S, Sulp FL, Sanka I, Pata P, Scheler O. Droplet-Based Technology for Studying the Phenotypic Effect of Microplastics on Antimicrobial Resistance. Proceedings. 2023; 92(1):41. https://doi.org/10.3390/proceedings2023092041
Chicago/Turabian StyleBartkova, Simona, Fenella Lucia Sulp, Immanuel Sanka, Pille Pata, and Ott Scheler. 2023. "Droplet-Based Technology for Studying the Phenotypic Effect of Microplastics on Antimicrobial Resistance" Proceedings 92, no. 1: 41. https://doi.org/10.3390/proceedings2023092041
