Use of Caenorhabditis elegans for Preselecting Lactobacillus Isolates To Control Salmonella Typhimurium

Abstract

Host-specific probiotics have been used to control enteric pathogens, including foodborne pathogens, in food animal production. However, evaluation of the efficacy of these probiotics requires costly in vivo assays in the target animal. The nematode Caenorhabditis elegans has been used for prescreening of antimicrobial agents and for studies of host-pathogen interactions. In the present study, 17 Lactobacillus isolates from chicken and pig intestines were tested with C. elegans, and the ability of these isolates to prevent death from Salmonella infection was variable. Two Lactobacillus isolates (S64, which gave full protection, and CL11, which gave no protection) were further studied. Both isolates exhibited a similar colonization profile in the C. elegans intestine. Although different culture fractions of CL11 were not protective, both live and heat-killed S64 cells provided full or partial protection of C. elegans from death caused by Salmonella infection. In contrast, different culture fractions from both isolates had similar effects on the colonization of the nematode intestine by Salmonella Typhimurium DT104. Our preliminary results from a pig performance trial revealed a correlation between the degree of protection in the C. elegans survival assay and the performance of 35-day-old weaned piglets that were treated with the same Lactobacillus isolates, suggesting that C. elegans can be used as a laboratory animal model for preselecting probiotics for control of Salmonella infections.

Caenorhabditis elegans Immune Conditioning with the Probiotic Bacterium Lactobacillus acidophilus Strain NCFM Enhances Gram-Positive Immune Responses

“…Interestingly, reports indicate that probiotic bacteria and several lactic acid bacteria (LAB) can enhance the host defense of C. elegans (11,43). Here we report that the Lactobacillus acidophilus strain NCFM, one of the most widely recognized probiotics that is extensively used in the food and pharmaceutical industries (2), significantly enhances the host defense response of C. elegans to Gram-positive pathogens.…”

The intestinal microbiota and its modulation for Salmonella control in chickens

“…Although microbiological assays can enhance the efficiency of screening, their effectiveness is often questionable. Recently, we evaluated a number of Lactobacillus isolates, which were able to inhibit Salmonella growth in microbiological assays, for their protection in Caenorhabditis elegans (a laboratory animal) infected with Salmonella Typhimurium (Wang et al, 2011). The isolates varied in their ability to protect the nematode from Salmonella infection-caused death, from full to no protection.…”

Lactobacillus zeae Protects Caenorhabditis elegans from Enterotoxigenic Escherichia coli-Caused Death by Inhibiting Enterotoxin Gene Expression of the Pathogen

“…Caenorhabditis elegans is a small free-living soil nematode that has been extensively used as an experimental in-vivo system for biological studies because of its small size, short generation time, suitability for genetic analysis. In particular, C. elegans has been used to study pathogen and host interactions of various bacterial pathogens, such as Pseudomonas aeruginosa [4], Salmonella enterica [5]–[7], Staphylococcus aureus [8], and Enterococcus faecalis [9]. In addition, the nematode has become increasingly used for screening antimicrobials, including preselecting probiotic bacteria for Salmonella control [7], [11], [12].…”