Silver Nanoparticle Targets Fabricated Using Chemical Vapor Deposition Method for Differentiation of Bacteria Based on Lipidomic Profiles in Laser Desorption/Ionization Mass Spectrometry

Abstract

The global threat of numerous infectious diseases creates a great need to develop new diagnostic methods to facilitate the appropriate prescription of antimicrobial therapy. More recently, the possibility of using bacterial lipidome analysis via laser desorption/ionization mass spectrometry (LDI-MS) as useful diagnostic tool for microbial identification and rapid drug susceptibility has received particular attention because lipids are present in large quantities and can be easily extracted similar to ribosomal proteins. Therefore, the main goal of the study was to evaluate the efficacy of two different LDI techniques—matrix-assisted (MALDI) and surface-assisted (SALDI) approaches—in the classification of the closely related Escherichia coli strains under cefotaxime addition. Bacterial lipids profiles obtained by using the MALDI technique with different matrices as well as silver nanoparticle (AgNP) targets fabricated using the chemical vapor deposition method (CVD) of different AgNP sizes were analyzed by the means of different multivariate statistical methods such as principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA), sparse partial least squares discriminant analysis (sPLS-DA), and orthogonal projections to latent structures discriminant analysis (OPLS-DA). The analysis showed that the MALDI classification of strains was hampered by interference from matrix-derived ions. In contrast, the lipid profiles generated by the SALDI technique had lower background noise and more signals associated with the sample, allowing E. coli to be successfully classified into cefotaxime-resistant and cefotaxime-sensitive strains, regardless of the size of the AgNPs. AgNP substrates obtained using the CVD method were used for the first time for distinguishing closely related bacterial strains based on their lipidomic profiles and demonstrate high potential as a future diagnostic tool for the detection of antibiotic susceptibility.

Metabolic profiling of bacteria with the application of polypyrrole-MOF SPME fibers and plasmonic nanostructured LDI-MS substrates

“…S9–S16 ). This aligns with previous investigation of our research group 44 , where silver nanostructured substrates enabled classification of the Escherichia coli strains into cefotaxime-resistant and cefotaxime-sensitive strains, while signals attributed to organic matrix hampered classification in case of application of MALDI.…”

Lipidomics Characterization of the Microbiome in People with Diabetic Foot Infection Using MALDI-TOF MS

“…The significant advantage of the proposed MALDI approach is that information about fatty acids composition is also provided; however, without the need of using a multistep protocol required when gas chromatography (the most traditional and old technique) is applied, which involves saponification of bacterial cells in sodium hydroxide, methylation with hydrochloric acid, lipid extraction, and a wash at a basic pH which typically takes several hours . The powerful impact of the MALDI approach in the differentiation of the bacteria based on their lipidomic profiles, even at the strain level, has been recently proven for E. coli strains isolated from DFI wounds that differed in beta-lactams antibiotic resistance level …”

“…In order to confirm the usefulness of such lipid enrichment profile in identifying a phenotype derived from DFI bacteria, further studies would be necessary to compare paired bacterial species colonizing non-DFI wounds. Recent studies showed that 2 h of incubation in the presence of antibiotic (cefotaxime in that case) is enough to detect distinctive lipid patterns of beta-lactam-resistant and -sensitive E. coli strains …”

MALDI-TOF as a powerful tool for identifying and differentiating closely related microorganisms: the strange case of three reference strains of Paenibacillus polymyxa

“…Moreover, considering the nature of our investigation into closely related species classification, it is worth noting that the analysis of the lower m/z range (up to m/z 2000) not only pertains to small peptides, as initially discussed, but also encompasses lipids. While our study primarily employed proteomics and genomics approaches, it is crucial to acknowledge that there exists a third option, namely MALDI lipidomics, which can offer valuable insights into the composition and variations of lipids within the studied strains 46 , 47 . This additional dimension of analysis could provide further support for the reliable classification of closely related species and enhance the comprehensiveness of our findings.…”