Phospholipids and Fatty Acids Affect the Colonization of Urological Catheters by Proteus mirabilis

Abstract

Proteus mirabilis-mediated CAUTIs are usually initiated by the adherence of bacteria to a urinary catheter surface. In this paper, three isolates of different origin and exhibiting different adhesion abilities were investigated in search of any changes in lipidome components which might contribute to P. mirabilis adhesion to catheters. Using GC-MS and LC-MS/MS techniques, 21 fatty acids and 27 phospholipids were identified in the examined cells. The comparison of the profiles of phospholipids and fatty acids obtained for catheter-attached cells and planktonic cells of the pathogens indicated C11:0 and PE 37:2 levels as values which could be related to P. mirabilis adhesion to a catheter, as well as cis C16:1, PE 32:0, PE 33:0, PE 38:2, PG 33:1, PG 34:0, PE 30:1, PE 32:1 and PG 30:2 levels as values which could be associated with cell hydrophobicity. Based on DiBAC4 (3) fluorescence intensity and an affinity to p-xylene, it was found that the inner membrane depolarization, as well as strong cell-surface hydrophobicity, were important for P. mirabilis adhesion to a silicone catheter. A generalized polarization of Laurdan showed lower values for P. mirabilis cells attached to the catheter surface than for planktonic cells, suggesting lower packing density of membrane components of the adherent cells compared with tightly packed, stiffened membranes of the planktonic cells. Taken together, these data indicate that high surface hydrophobicity, fluidization and depolarization of P. mirabilis cell membranes enable colonization of a silicone urinary catheter surface.

Combined Application of Aminoglycosides and Ascorbic Acid in the Elimination of Proteus mirabilis Rods Responsible for Causing Catheter-Associated Urinary Tract Infections (CAUTIs)—A Molecular Approach

“…In addition to the above, PE 32:2 was also one of the most abundant PLs in the adherent cells. The variety in the phospholipid composition of planktonic and adherent cells was discussed in detail in our previous work [ 25 ].…”

“…The cumulative content of these two fatty acids ranged from 52% in the C12 planktonic cells to 72% in the ATCC 29906 adherent cells. The differences in the fatty acid composition of the planktonic and adherent cells was described in detail in our previous paper [ 25 ].…”

“…The C12 strain was obtained from the Department of Biology of Bacteria (University of Lodz, Lodz, Poland), while the reference strain ATCC 29906 was purchased from the American Type Culture Collection (Manassas, VA, USA). Our previous studies were carried out on these strains [ 25 ].…”

“…Coverage of the silicone catheter surface by uropathogenic cells was examined according to the MTT tetrazolium reduction assay described previously [ 25 ]. The catheter pieces devoid of unattached bacterial cells were placed in a 96-well plate containing a mixture consisting of 150 µL of modified TSB medium and 15 µL of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (Merck, Darmstadt, Germany) solution (5 mg mL −1 in phosphate-buffered saline) (PBS; Thermo Fisher Scientific, Waltham, MA, USA)).…”

“…The lipids were determined according to our method described earlier [ 25 ] using an ExionLC AC (Sciex, Framingham, MA, USA) UHPLC system and a 4500 Q-TRAP mass spectrometer equipped with an ESI source. A total of 10 µL of lipid extract was injected onto an Eclipse XDB-C18, 50 mm × 4.6 mm, 1.8 µm column (Agilent, Santa Clara, CA, USA), heated at 40 °C, with the flow rate of 500 μL min −1 .…”