Pseudomonas aeruginosa responds to exogenous polyunsaturated fatty acids (PUFAs) by modifying phospholipid composition, membrane permeability, and phenotypes associated with virulence

Abstract

BackgroundPseudomonas aeruginosa, a common opportunistic pathogen, is known to cause infections in a variety of compromised human tissues. An emerging mechanism for microbial survival is the incorporation of exogenous fatty acids to alter the cell’s membrane phospholipid profile. With these findings, we show that exogenous fatty acid exposure leads to changes in bacterial membrane phospholipid structure, membrane permeability, virulence phenotypes and consequent stress responses that may influence survival and persistence of Pseudomonas aeruginosa.ResultsThin-layer chromatography and ultra performance liquid chromatography / ESI-mass spectrometry indicated alteration of bacterial phospholipid profiles following growth in the presence of polyunsaturated fatty acids (PUFAs) (ranging in carbon length and unsaturation). The exogenously supplied fatty acids were incorporated into the major bacterial phospholipids phosphatidylethanolamine and phosphatidylglycerol. The incorporation of fatty acids increased membrane permeability as judged by both accumulation and exclusion of ethidium bromide. Individual fatty acids were identified as modifying resistance to the cyclic peptide antibiotics polymyxin B and colistin, but not the beta-lactam imipenem. Biofilm formation was increased by several PUFAs and significant fluctuations in swimming motility were observed.ConclusionsOur results emphasize the relevance and complexity of exogenous fatty acids in the membrane physiology and pathobiology of a medically important pathogen. P. aeruginosa exhibits versatility with regard to utilization of and response to exogenous fatty acids, perhaps revealing potential strategies for prevention and control of infection.Electronic supplementary materialThe online version of this article (10.1186/s12866-018-1259-8) contains supplementary material, which is available to authorized users.

Exogenous polyunsaturated fatty acids (PUFAs) promote changes in growth, phospholipid composition, membrane permeability and virulence phenotypes in Escherichia coli

“…2). Compared to other similarly performed analyses from our laboratory [1][2][3][4], the migratory shifts were much less pronounced, suggesting a lower degree of PUFA incorporation. Subsequent UPLC/MS analyses con rmed at least some degree of incorporation of all fatty acids except 22:6 into PE and PG.…”

“…No longer are fatty acids merely a carbon source destined for b-oxidation; they represent multipurpose molecules capable of nutritional value, membrane phospholipid remodeling, and signalmediated behavioral control. Previous studies from our laboratory have explored these phenomena in several medically important bacteria, including Vibrio species, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumanii [1][2][3][4]; however, an analysis of the model organism E. coli had not been performed.…”

“…The observed alteration to membrane permeability led to an investigation of the impact of fatty acids on antimicrobial peptide susceptibility, a phenomenon previous documented for several Gram-negative bacteria [1][2][3][4]. For these experiments, two antimicrobials (polymyxin B and colistin) with mechanisms of action that target membrane bilayers via biophysical intercalation were chosen to compare with an antibiotic (ampicillin) that relies on protein-mediated uptake for activity.…”

“…An emerging body of evidence has highlighted the expanded fatty acid handling characteristics of Gramnegative bacteria. The impacts of fatty acids acquired from growth media include phospholipid remodeling and phenotypes affecting growth and virulence [1][2][3][4]. The expanded utility of fatty acids magni es the relevance of environmental adaptation for bacteria, especially those that oscillate between host and aquatic niches.…”

Interactions of Gold and Silver Nanoparticles with Bacterial Biofilms: Molecular Interactions behind Inhibition and Resistance

“…Due to their hydrophobic nature, lipids are engaged in different types of interactions with AuNPs and AgNPs. For example, in a report published by Bakri et al, the authors proposed interactions of lipid-coated AuNPs with the biomembrane of bacteria [ 65 ]. They used 1,2-distearoyl-sn-glycero-3-phosphorylethanolamine-coated gold nanorods (DSPE-AuNRs) against P. aeruginosa and suggested that DSPE interacts with bacterial lipid membrane via hydrophobic interactions and destabilizes it ( Figure 5 A,B).…”