Phenotypic changes in the lipopolysaccaride of Pseudomonas aeruginosa and E.coli grown in milk-based enteral nutrient solutions.



Hodgson, Ian and Stewart, John and Fyfe, Lorna (1999) Phenotypic changes in the lipopolysaccaride of Pseudomonas aeruginosa and E.coli grown in milk-based enteral nutrient solutions. Nutrition, 15 (1). pp. 11-17. ISSN 0899-9007, ESSN: 1873-1244

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Abstract

Previous studies have shown enteral nutritional solutions (ENS) contaminated with large numbers of microorganisms from the environment or gastrointestinal (GI) tract of patients have caused respiratory infections, acute and chronic enteritis, and septicemia. The introduction of “closed” enteral feeding systems has been used to prevent contaminating organisms from entering enteral feeding systems in large numbers. However, there is some discussion as to whether this has been an effective measure in reducing ENS-related infections because there is anecdotal evidence to suggest that disease processes resulting from enteral feeding are still commonplace in the hospital and home. This is because there is very little information about the growth of microorganisms in ENS and whether growth in ENS may affect the virulence and pathogenicity of microorganisms. This study shows that Escherichia coli and Pseudomonas aeruginosa may grow at 25°C from either high or low initial numbers to up to 9.2 log colony-forming units per mL in a range of milk-based ENS. However, these organisms did not grow in the fruit-based ENS. The effect on the lipopolysaccharide (LPS) of culturing E. coli and P. aeruginosa in milk-based ENS as opposed to standard laboratory media was examined using polyacrylamide gel electrophoresis. We found that there were significant qualitative changes in the phenotype of O-polysaccharide side chains of the LPS from these organisms. O-polysaccharide is known to mediate in the complement, antibiotic and bile resistance, and affect adherence. Therefore, changes in the virulence and pathogenicity of these microorganisms when cultured in ENS may be indicated. Thus, the study provides further evidence for reevaluating the microbiologic and immunologic effects of enteral feeding, especially on the microbial flora of the GI tract.

Item Type: Article
Uncontrolled Keywords: enteral nutrition solutions; bacterial growth; lipopolysaccharide; phenotypic changes; O-polysaccharide
Divisions: School of Health Sciences > Dietetics, Nutrition and Biological Sciences
Date Deposited: 11 Dec 2012 11:23
Last Modified: 19 Mar 2014 13:00
URI: http://eresearch.qmu.ac.uk/id/eprint/3037

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