Open Access4‐Amino‐4‐deoxy‐ l ‐arabinose in LPS of enterobacterial R‐mutants and its possible role for their polymyxin reactivity
Author(s) -
Boll Matthias,
RadziejewskaLebrecht Joanna,
Warth Christoph,
KrajewskaPietrasik Danuta,
Mayer Hubert
Publication year - 1994
Publication title -
fems immunology & medical microbiology
Language(s) - English
Resource type - Journals
eISSN - 1574-695X
pISSN - 0928-8244
DOI - 10.1111/j.1574-695x.1994.tb00460.x
Subject(s) - microbiology and biotechnology , biology , polymyxin , mutant , polymyxin b , reactivity (psychology) , arabinose , antibiotics , biochemistry , medicine , fermentation , alternative medicine , pathology , xylose , gene
The content of 4‐amino‐4‐deoxy‐ l ‐arabinopyranose ( l ‐Arap4N) and the phosphate substitution pattern of the LPS of various strains from Salmonella minnesota, Yersinia enterocolitica and Proteus mirabilis was determined by GC/MS, HPLC and 31 P‐NMR. These data allowed us to examine the possible role of these components for the polymyxin B‐binding capacity of LPS and for the minimal inhibiting concentration (MIC) and the minimal bactericidal concentration (MBC) of polymyxins B and E towards the respective R‐mutants. Contrary to other investigated Re‐, Rd‐ and Rc‐mutants of S. minnesota , strain R595 (Re‐mutant) showed about a 90% substitution of the ester‐linked phosphate‐group with l ‐Arap4N, whereas the l ‐Arap4N content of the other S. minnesota strains amounted to 17–25%. Neither the binding capacity of LPS to polymyxin B, determined by a bioassay, nor the MIC‐ and MBC‐values of the R‐mutants were significantly affected by this alteration. Similar results were obtained after using the temperature‐dependent changes in the l ‐Ara p4N‐content and phosphate substitution pattern of Y. enterocolitica 75R . In order to explore the relevant polymyxin B binding site, lipid A samples with or without substitution of their ester‐linked phosphate group were prepared and subjected to the polymyxin‐binding assay. The results obtained so far indicated that the inner core bound l ‐Arap4N, detected in all resistant strains investigated, may play a decisive role in the decreased binding of polymyxin B, responsible for the bacterial resistance towards polymyxin(s).