Browsing by Person "Hodgson, Ian"

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Inhibition of bacteria and yeast by oil of fennel and paraben: Development of synergistic antimicrobial combinations
(Taylor & Francis, 1998) Hodgson, Ian; Stewart, John; Fyfe, Lorna
This study describes inhibitory properties of combinations of oil of fennel and paraben (methyl, ethyl or propyl) against C. albicans, E. coli and S. aureus. Bacteria or yeast were cultured in broth at 25C and viable counts were measured over a period of 24 h. E. coli was particularly sensitive to inhibition by each combination where there was <10 of units/mL at all times of culture. C. albicans and S. aureus were less susceptible to inhibition by the combination of oil of fennel and methyl paraben but very susceptible to inhibition by oil of fennel in combination with propyl paraben where after 4 h there was <10 cf units/mL. Synergistic inhibition by one or more combinations was evident against each microbe.
Phenotypic changes in the lipopolysaccaride of Pseudomonas aeruginosa and E.coli grown in milk-based enteral nutrient solutions
(Elsevier, 1999-01) Hodgson, Ian; Stewart, John; Fyfe, Lorna
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 25C 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.