Cinnamomum cassia and Syzygium aromaticum Essential Oils Reduce the Colonization of Salmonella Typhimurium in an In Vivo Infection Model Using Caenorhabditis elegans

Abstract

The regulation of intestinal colonization in livestock by means of non-bactericidal additives is an important management lever for zoonotic bacteria such as Salmonella spp. Caenorhabditis elegans is proposed here as a model for the evaluation of five essential oils (EOs) as anti-colonization products against Salmonella Typhimurium. An evaluation of the toxicity of EOs for C. elegans showed LD50 values ranging from 74.5 ± 9.6 µg/mL for Cinnamomum cassia (CEO) to 271.6 ± 14.9 µg/mL for Syzygium aromaticum (SyEO). Both EOs significantly inhibited bacterial colonization in the digestive tract of C. elegans with reductions of 0.88 and 0.70 log CFU/nematode at nontoxic concentrations of 50 µg/mL and 150 µg/mL, respectively. With the minimal bactericidal concentrations of CEO and SyEO against S. Typhimurium being 312.5 µg/mL and 625 µg/mL, respectively, an antibacterial effect can be excluded to explain the inhibition of the bacterial load. The anti-colonizing activity of these two EOs could, however, be related to an inhibition of the swimming motility, which was significantly reduced by 23.47% for CEO at 50 µg/mL and 19.56% for SyEO at 150 µg/mL. This study shows the potential of C. elegans as a predictive in vivo model of anti-colonizing activities that is suitable for the evaluation of essential oils.

The Use of Star Anise-Cinnamon Essential Oil as an Alternative Antibiotic in Prevention of Salmonella Infections in Yellow Chickens

“…The curli proteins, which are adhesive fimbrial structures encoded by csgDEFG and csgBAC , are responsible for biofilm formation on biotic or abiotic surfaces, representing a major component of the extracellular matrix in biofilms [ 30 ]. Trans-cinnamaldehyde was shown to reduce the colonization ability of Salmonella typhimurium in the digestive tract [ 31 ]. However, SCEO used in this study had the effect of reducing the colonization of Salmonella pullorum and Salmonella give but not Salmonella kentucky in the cecum.…”

Essential oils mix effect on chicks ileal and caecal microbiota modulation: a metagenomics sequencing approach

“…This study aimed, therefore, to investigate, using amplicon sequencing, in time, the effect of a complex and well-defined combination of EOs feed supplement on both ileal and caecal chicken microbiota. EOs have already been proven to express an antibacterial activity against foodborne pathogens in vitro ( 29 , 43 ) but diminished effects in vivo ( 44 , 45 ). As Salmonella and Campylobacter are significant members of the chicken microbiota but may not always be naturally present, we ensured their presence by manually inoculating these foodborne pathogens into the birds.…”

The nematode worm Caenorhabditis elegans as an animal experiment replacement for assessing the virulence of different Salmonella enterica strains

“…The role of C. elegans as an alternative to animal experiments is being continuously discussed and investigated. The range of applications of the model is extensive and includes nutritional studies on probiotic host interactions, immunity, and infection and studies on the antimicrobial effects of food supplements (Lang et al, 2021;Chakravarty, 2022;Zermeño-Ruiz et al, 2022). The application of genetically modified microorganisms could reveal details on the infection mechanisms, e.g., of S. Typhimurium, and the host response of C. elegans, where several anti-microbiotic protein pathways have been identified to be linked to the reaction of Salmonella virulence factors (Tenor et al, 2004;Sahu et al, 2013).…”