Characterization of Pseudomonas aeruginosa biofilms grown on different substrates by means of FT-IR spectroscopy.

Fourier Transform Infrared Spectroscopy (FT-IR) is a vibrational technique largely adopted for the study of bacterial biofilms [1]. FT-IR is a non-destructive method, that allows multiple analyses of the same biofilm, without damaging the bacteria [2, 3].

Pseudomonas aeruginosa represents a class of bacteria largely investigated since it is an opportunistic pathogen and it is now considered to be a primary infectious agent especially for its ability to form multi-resistant biofilms [4].

In the present investigation, we aimed to characterize P. aeruginosa biofilms grown on different substrates to define better experimental conditions more useful for investigating the interaction of these biofilms with external agents. In particular, we investigated biofilms grown on Teflon membranes, CaF₂ windows, and MirrIR slides (specific reflection FT-IR spectroscopy microscope slides). Different geometries were used for collecting spectra using the microscope stage of a Perkin Elmer Spectrum One spectrometer equipped with a mercury cadmium telluride (MCT) detector.

Multiple acquisitions of spectra were done, and statistical criteria were applied for monitoring and comparing them. The positive and negative aspects of the different examined substrates for biofilm formation and acquisition modes are presented and discussed.

References

[1] Amy R. Crisp, Bryn Short, Laurence Rowan, Gordon Ramage, Ihtesham U.R. Rehman, Robert D. Short, Craig Williams, Investigating the chemical pathway to the formation of a single biofilm using infrared spectroscopy. Biofilm, 6, 2023, 100141, doi.org/10.1016/j.bioflm.2023.100141.

[2] Alvarez-Ordonez, A, Mouwen DJM, Lopez M, Prieto M. J Microbiol Methods 2011; 84:369–78.

[3] Z. Pang, R. Raudonis, B.R. Glick, T. Lin, Z. Cheng, Antibiotic resistance in Pseudomonas aeruginosa: mechanisms and alternative therapeutic strategies, Biotechnol. Adv. [Internet]. 37 (1) (2019) 177–192. Available from: 10.1016/j.biotechadv.2018.11.013.

[4] Thi MTT, Wibowo D, Rehm BHA. Pseudomonas aeruginosa Biofilms. Int J Mol Sci. 2020 Nov 17;21(22):8671. doi: 10.3390/ijms21228671.