Monitoring of Bactericidal Effects of Silver Nanoparticles Based on Protein Signatures and VOC Emissions from Escherichia coli and Selected Salivary Bacteria

Abstract

Escherichia coli and salivary Klebsiella oxytoca and Staphylococcus saccharolyticus were subjected to different concentrations of silver nanoparticles (AgNPs), namely: 12.5, 50, and 100 µg mL−1. Matrix-assisted laser desorption/ionization–time-of-flight mass spectrometry (MALDI-TOF MS) spectra were acquired after specified periods: 0, 1, 4, and 12 h. For study of volatile metabolites, headspace solid-phase microextraction coupled to gas chromatography/mass spectrometry (HS-SPME-GC-MS) was employed—AgNPs were added to bacteria cultures and the headspace was analyzed immediately and after 12 h of incubation. Principal components analysis provided discrimination between clusters of protein profiles belonging to different strains. Canonical correlation, network analysis, and multiple linear regression approach revealed that dimethyl disulfide, dimethyl trisulfide, 2-heptanone, and dodecanal (related to the metabolism of sulfur-containing amino acids and fatty acids synthesis) are exemplary molecular indicators, whose response variation deeply correlated to the interaction with bacteria. Therefore, such species can serve as biomarkers of the agent’s effectiveness. The present investigation pointed out that the used approaches can be useful in the monitoring of response to therapeutic treatment based on AgNPs. Furthermore, biochemical mechanisms enrolled in the bactericidal action of nanoparticles can be applied in the development of new agents with enhanced properties.

Construction of multifunctional porcine acellular dermal matrix hydrogel blended with vancomycin for hemorrhage control, antibacterial action, and tissue repair in infected trauma wounds

“…However, Ag NPs are cytotoxic [ [16] , [17] , [18] ] i.e. they cause cell membrane damage [ 19 ], DNA damage [ 20 ], oxidative stress [ 21 ], and the formation of reactive oxygen species (ROS) [ 22 ]. Staphylococcus aureus ( S. aureus ) is the most common type of bacterium that causes skin infection [ 23 , 24 ].…”

Metabolic Profiling of VOCs Emitted by Bacteria Isolated from Pressure Ulcers and Treated with Different Concentrations of Bio-AgNPs

“…Indeed, previous studies on molecular profiles of Gram-positive and Gram-negative bacteria, showed that this first group presented to be superior is terms of resistance against bio-AgNPs, especially when a longer incubation time with the agent is considered. Protein patterns acquired by MALDI–TOF–MS technique for S. saccharolyticus were resumed after 12 h of incubation with bio-AgNPs, while Gram-negative species suffered more extensive alteration of their original molecular profiles [ 21 ]. The negative charges of lipopolysaccharides composing the outer membrane of Gram-negative bacteria probably exert attraction on the residual positive charges from nanoparticles.…”

“…In addition, VOC trends can be correlated with physiological parameters (e.g., growth profile and possibly active pathways) and serve as indicators of agent effectuality. Such an experimental approach was previously explored for the investigation of bacterial volatiles generated by salivary bacteria [ 20 , 21 ]. The headspace of bacteria incubated with AgNPs at a fixed concentration was assessed at different time points, in order to obtain a qualitative snapshot of the current VOC emissions—the results suggested bacteria inhibition due to noticed alterations in the production of metabolic markers [ 20 ].…”

“…The headspace of bacteria incubated with AgNPs at a fixed concentration was assessed at different time points, in order to obtain a qualitative snapshot of the current VOC emissions—the results suggested bacteria inhibition due to noticed alterations in the production of metabolic markers [ 20 ]. The fold-change of bacterial VOCs after AgNPs-treatment was correlated with paired alterations in protein profiles; the observed relationships were modeled to predict the effectiveness of the interaction bacteria-agent [ 21 ].…”

Special Issue “Saliva and Oral Diseases”

“…In this regard, biomarkers are explored that can be measured using simple, innocuous, painless and low-cost tests for use in clinical practice. The study [ 6 ] of variations in the concentration of TNF-α, IL-2, INF-γ, IL-10, nitric oxide, peroxynitrite, S-nitrosothiols and nitrotyrosine contributes to further our knowledge on the pathogenesis of psoriasis.…”