ATR-FTIR Spectroscopy Analysis of Biochemical Alterations in Pseudomonas aeruginosa Biofilms Following Antibiotic and Probiotic Treatments

Pseudomonas aeruginosa is a well-studied bacterium, recognized as a primary infectious agent due to its capacity to form multi-resistant biofilms. Various strategies to inhibit the pathogenic activity and biofilm formation of Pseudomonas aeruginosa are under investigation. This study examines the interaction between these pathogenic biofilms and the antibiotic Tobramycin, both in the presence and absence of supernatants from the probiotic organism, Lactiplantibacillus plantarum, using Fourier transform infrared (FTIR) spectroscopy. A Universal Attenuated Total Reflection accessory enabled rapid acquisition of infrared spectra from Pseudomonas aeruginosa biofilms grown on Teflon membranes and subsequently exposed to antibiotic and/or probiotic agents. Spectral changes induced by these agents were analyzed using deconvolution procedures, difference spectra, and ratiometric analysis. The results show that antibiotic treatment modifies the lipid, protein, nucleic acid, and carbohydrate components of bacterial biofilms. Specifically, the spectral analysis suggests that antibiotic treatment alters membrane structural organization, inhibits protein synthesis, and affects sugar and polysaccharide production. Additional treatment with a probiotic agent further changes the characteristics of the bacterial biofilm. FTIR spectroscopy with the Attenuated Total Reflection spectra collection geometry is confirmed as an effective method for rapid spectral acquisition and the use of Teflon membranes further facilitates the application of this vibrational technique in microbiology.