Evaluation of Thymol-β-d-Glucopyranoside as a Potential Prebiotic Intervention to Reduce Carriage of Zoonotic Pathogens in Weaned and Feeder Pigs.

Gizem Levent,Michael E Hume,David J Nisbet,Roger B Harvey,Toni L Poole,Haiqi He,Ross C Beier,Robin C Anderson,Branko Petrujkić,Kenneth J Genovese

doi:10.3390/microorganisms9040860

Abstract

The gut of food-producing animals is a reservoir for foodborne pathogens. Thymol is bactericidal against foodborne pathogens but rapid absorption of thymol from the proximal gut precludes the delivery of effective concentrations to the lower gut where pathogens mainly colonize. Thymol-β-d-glucopyranoside is reported to be more resistant to absorption than thymol in everted jejunal segments and could potentially function as a prebiotic by resisting degradation and absorption in the proximal gut but being hydrolysable by microbial β-glycosidase in the distal gut. Previous in vitro studies showed bactericidal effects of thymol-β-d-glucopyranoside against Campylobacter, Escherichia coli, and Salmonella enterica serovar Typhimurium in the presence but not absence of intestinal microbes expressing β-glycosidase activity, indicating that hydrolysis was required to obtain antimicrobial activity. Presently, the oral administration of thymol-β-d-glucopyranoside was studied to examine the effects on intestinal carriage of Campylobacter, E. coli, and S. Typhimurium in swine. The effects of thymol-β-d-glucopyranoside or thymol on antimicrobial sensitivity of representative E. coli isolates and characterized Salmonella strains were also explored. Results from two in vivo studies revealed little antimicrobial effects of thymol-β-d-glucopyranoside on Campylobacter, E. coli, or S. Typhimurium in swine gut. These findings add credence to current thinking that hydrolysis and absorption of thymol-β-d-glucopyranoside and thymol may be sufficiently rapid within the proximal gut to preclude delivery to the distal gut. Antibiotic susceptibilities of selected bacterial isolates and strains were mainly unaffected by thymol. Further research is warranted to overcome obstacles, preventing the delivery of efficacious amounts of thymol-β-d-glucopyranoside to the lower gut.

Highlights

Campylobacter and non-typhoidal Salmonella are leading bacterial causes of human foodborne illness that are estimated to cause 1.5 and 1.35 million human infections, respectively, every year in the United States [1,2]
In our second study, which was done to assess the potential impact of an older distal gut flora on the antimicrobial activity of thymol-β-D-glucopyranoside, we examined the use of two dose levels
The gut of pigs can be colonized with important foodborne and disease-causing bacteria such as Campylobacter, E. coli, and Salmonella

Summary

Introduction

Campylobacter and non-typhoidal Salmonella are leading bacterial causes of human foodborne illness that are estimated to cause 1.5 and 1.35 million human infections, respectively, every year in the United States [1,2]. Swine, and cattle can harbor these pathogens within their digestive tracts and risk contaminating carcasses during processing. The increasing number of antibiotic-resistant Campylobacter and Salmonella isolates recovered from human infections has become a serious public health threat [1]. Antibiotic use in these animals may select for antibiotic resistant bacteria which can result in serious public health consequences [3]. A non-antibiotic pre-harvest strategy is needed to reduce the risk of carcass contamination at the abattoir and to reduce the risk of selection of antibiotic resistant pathogens that can pose a greater risk for public health.

Objectives

Methods

Conclusion