Giles, David K.
Sompayrac, Joanie; Potts, Gretchen; Bell, Rebekah
University of Tennessee at Chattanooga
Place of Publication
AIM: The purpose of this experiment was to determine whether or not Enterobacter aerogenes, Acinetobacter baumannii, and Klebsiella pneumoniae, which are three gram negative bacteria commonly found on the skin, utilize fatty acids in a manner that affects bacterial phenotype. Furthermore, an objective was to gain a deeper understanding of how the alteration of bacterial membranes, as a result of fatty acid uptake, affected the pathogenicity, membrane permeability, and resistance in gram negative bacteria. METHODS: The lipids were extracted using the method of Bligh and Dyer and analyzed using thin-layer chromatography (TLC). A series of tests were performed, including a hydrophobic compound uptake test, lactic acid stress test, and osmotic pressure stress test, before analyzing lipids with high performance liquid chromatography (HPLC). RESULTS: TLC of isolated phospholipids from E. aerogenes, K. pneumoniae, and A. baumannii revealed an altered phospholipid migrational pattern when micromolar concentrations of γ-linolenic acid were supplemented to the growth media. When 18:3 was added to A. baumannii, there was decreased uptake of hydrophobic compounds, decreased membrane permeability, and better survivability under osmotic pressure and lactic acid stress. Addition of linoleic acid (18:2) did not affect the permeability as much as addition of γ-linolenic (18:3) or dihomo-γ-linolenic acid (20:3). CONCLUSION: A. baumannii alters its membrane according to exogenous fatty acid unsaturation and acyl chain length. Exposure of A. baumannii to three fatty acids resulted in an ability for the bacteria to uptake hydrophobic compounds. Since A. baumannii is a multiple drug resistant nosocomial pathogen, it is significant that its exposure to lotion-containing (and host-derived) fatty acids and salt can make the bacteria more refractive to hydrophobic compounds, as well as impact stress survival in vitro.
B. I. S.; An honors thesis submitted to the faculty of the University of Tennessee at Chattanooga in partial fulfillment of the requirements of the degree of Bachelor of Integrated Studies.
Sin -- Microbiology; Host-bacteria relationships; Drug resistance in microorganisms
Eder, Adrianna, "The effects of lotion fatty acids on gram negative skin flora: implications for membrane remodeling and pathogenicity" (2015). Honors Theses.