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

Lipidomic profiling has emerged as a powerful tool for
the comprehensive
characterization of bacterial species, particularly in the context
of clinical diagnostics. Utilizing matrix-assisted laser desorption/ionization
time-of-flight mass spectrometry (MALDI-TOF MS), this study aims to
elucidate the lipidomic landscapes of bacterial strains isolated from
diabetic foot infections (DFI). Our analysis successfully identified
a diverse array of lipids in the cellular membranes of both Gram-positive
and Gram-negative bacteria, revealing a total of 108 unique fatty
acid combinations. Specifically, we identified 26 LPG, 33 LPE, 43
PE, 114 PG, 89 TAG, and 120 CLP in Gram-positive bacteria and 10 LPG,
14 LPE, 124 PE, 37 PG, 13 TAG, and 22 CLP in Gram-negative strains.
Key fatty acids, such as palmitic acid, palmitoleic acid, stearic
acid, and oleic acid, were prominently featured. Univariate analysis
further highlighted distinct lipidomic signatures among the bacterial
strains, revealing elevated levels of phosphatidylethanolamine (PE)
and phosphatidylglycerol (PG) in Gram-negative bacteria associated
with DFI. In contrast, Gram-positive strains demonstrated increased
or uniquely fluctuating levels of triglyceride (TAG) and cardiolipin
(CLP). These findings not only underscore the utility of MALDI-TOF
MS in bacterial lipidomics but also provide valuable insights into
the lipidomic adaptations of bacteria in diabetic foot infections,
thereby laying the groundwork for future studies aimed at constructing
microbial lipid libraries for enhanced bacterial identification.