Structural modifications occurring in lipid A of Bordetella bronchiseptica clinical isolates as demonstrated by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry

Abstract

Bordetella bronchiseptica is a respiratory pathogen in mammal species and its cell surface lipopolysaccharide-endotoxin is a potent virulence factor. In order to better characterize the endotoxin structure to virulence relationships, we studied the lipid A structures of B. bronchiseptica isolates from human and rabbit origins as a function of their virulence phases. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) has been widely used for the structural characterization of bacterial endotoxins and their lipid A moieties. This method combined with chemical analytical methods proved to be essential for the characterization of small samples and discrete but essential structural modifications. The occurrence of palmitate (C(16)) in the B. bronchiseptica lipid A structures is shown for the first time at two sites. Their presence was also demonstrated for the first time in correlation with the virulence phase of B. bronchiseptica clinical isolates. The recently identified glucosamine modifications of Bordetella lipids A are also reported in these isolates.

Role of pagL and lpxO in Bordetella bronchiseptica Lipid A Biosynthesis

“…While this does not rule out their existence, it means that they would be present at very low abundance in our analyses (i.e., precursor ions corresponding to lipid A structures with the addition of a second GlcN or palmitate were not distinguishable at the existing signal-to-noise ratio). While the conclusions of Basheer et al (2) are broadly in agreement with the findings reported here, detailed data supporting the identification of the second GlcN and palmitate modifications were not presented in the paper. We suggest the use of high-resolution mass spectrometry, including tandem mass spectrometry, as a requirement for accurate lipid A structure determination from mass spectrometry-based experiments.…”

Unique Structural Modifications Are Present in the Lipopolysaccharide from Colistin-Resistant Strains of Acinetobacter baumannii

“…For example, the addition of positively charged residues including ethanolamine, aminoarabinose, and glucosamine to lipid A modulates CAMP resistance ( Fig. 1) (7)(8)(9).…”

Structure activity characterization of Bordetella petrii lipid A, from environment to human isolates

“…Reduced host-cell recognition followed by an attenuated innate immune response may result in chronic (macrophage and monocytic) rather than acute (neutrophilic) inflammatory responses [43]. The presence of 2-hydroxydodecanoic acid (12:0(2-OH)) was reported earlier in B. bronchiseptica by our group [24], it was also more recently shown in B. avium, B. trematum and B. hinzii [4] together with the demonstration of the lpxO homologs in the genomes.…”