ISSN:
1574-695X
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
,
Medicine
Notes:
Abstract 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 31P-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).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1574-695X.1994.tb00460.x
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