Effect of immunomodulation and alteration of GI microbiota by a novel Lactobacillus rhamnosus strain in the Sprague Dawley rats

Jia-chi Chiou, Tim Fat Shum, Haicui Wu

Research output: Unpublished conference presentation (presented paper, abstract, poster)Conference presentation (not published in journal/proceeding/book)Academic research


Probiotics have been known to modulate the gut microbiota and involved in the immunomodulation of GI tract. This study aims to demonstrate the effect of selected probiotic strains isolated from Hong Kong on the immunomodulation of health rats and rats suffered from inflammatory bowel diseases (IBDs).

Twelve probiotic species including Lactobacillus spp., Leuconostoc spp. and Pediococcus spp. were isolated from various sources such as infant feces and different food types. The properties of these probiotics to tolerate the gastric juice and antimicrobial activity were tested in vitro while the adhesion of these strains onto the enterocytes was determined using human intestinal epithelial Caco-2 cells in the absence and presence of pathogenic bacteria. Changes of pro-inflammation cytokines IL-6 and IL-8 upon pathogen infections were determined in the absence and presence of selected probiotic strains.

Except the L. sakei isolate, other Lactobacillus spp. harbored relatively high acid and bile salts tolerance. These isolated probiotics inhibited the growth of some common foodborne pathogens such as Staphylococcus aureus, Bacillus cereus, Pseudomonas aeruginosa, Acinetobacter baumannii and Salmonella enterica serovar Paratyphi mainly via acid production and/or other antimicrobial substances. Two isolates, namely L. rhamnosus S1 and L. plantarum S13, reduce the adhesion of Klebsiella pneumoniae and S. aureus on the Caco-2 cells by 40% and 32% respectively. Moreover, L. rhamnosus S1 further reduced the production of pro-inflammatory cytokine IL-8 stimulated by S. aureus, A. baumannii and Enterococcus faecium.

The selected probiotic strains showed good performance on the tolerance to the gastric juice and antimicrobial properties against several foodborne pathogens. The results of competitive adhesion and cytokine production further implied that the selected probiotic strains harbor competitive adhesion ability to compete out the pathogens in the GI tract, which could contribute to reduced IL-8 production due to the pathogens infection. Further study of administrating alive probiotic strains to the animals and monitor their effects on the inflammatory response are currently in progress.

Health and Medical Research Fund, Food and Health Bureau, Hong Kong Government
Food Safety and Technology Research Centre, Hong Kong Polytechnic University
Original languageEnglish
Publication statusPublished - 13 Mar 2019
EventKeystone Symposia -
Duration: 1 Jan 2009 → …


ConferenceKeystone Symposia
Period1/01/09 → …


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