Searching for the one(s): Using Probiotics as Anthelmintic Treatments

Abstract

Helminths are a major health concern as over one billion people are infected worldwide and, despite the multiple efforts made, there is still no effective human vaccine against them. The most important drugs used nowadays to control helminth infections belong to the benzimidazoles, imidazothiazoles (levamisole) and macrocyclic lactones (avermectins and milbemycins) families. However, in the last 20 years, many publications have revealed increasing anthelmintic resistance in livestock which is both an economical and a potential health problem, even though very few have reported similar findings in human populations. To deal with this worrying limitation of anthelmintic drugs, alternative treatments based on plant extracts or probiotics have been developed. Probiotics are defined by the Food and Agriculture Organization as live microorganisms, which, when consumed in adequate amounts, confer a health benefit to the host. It has been proven that probiotic microbes have the ability to exert an immunomodulatory effect both at the mucosa and the systemic level. The immune response against gastrointestinal helminths is characterized as a type 2 response, with high IgE levels, increased numbers and/or activity of Th2 cells, type 2 innate lymphoid cells, eosinophils, basophils, mast cells, and alternatively activated macrophages. The oral administration of probiotics may contribute to controlling gastrointestinal helminth infections since it has been demonstrated that these microorganisms stimulate dendritic cells to elicit a type 2 or regulatory immune response, among other effects on the host immune system. Here we review the current knowledge about the use of probiotic bacteria as anthelmintic therapy or as a complement to traditional anthelmintic treatments. Considering all research papers reviewed, we may conclude that the effect generated by probiotics on helminth infection depends not only on the parasite species, their stage and localization but also on the administration scheme.

Probiotics beyond the farm: Benefits, costs, and considerations of using antibiotic alternatives in livestock

“…Moreover, the value of probiotics is beginning to expand beyond their common mechanisms. Researchers now recognize their ability to mediate viral, fungal, and parasitic infections (Hsu et al, 2018;Saracino et al, 2021;Zuckermann et al, 2022), mitigate the negative effects of heat stress (Jiang et al, 2021), and reduce environmental ammonia and methane emissions generated from livestock and poultry manure (Prenafeta-Boldúet al, 2017;Such et al, 2021). Probiotic strains with these capabilities may then be subsequently applied as fertilizer in adjacent crop fields where they might even improve terrestrial and aquatic ecosystem processes as described earlier.…”

Gastrointestinal worms and bacteria: From association to intervention

“…21,22 Such strategies aim at (re)shaping gut microbial communities, for instance, through the administration of (i) bioactive dietary components (e.g., prebiotics) or (ii) non-resident bacteria, including probiotics, bespoke bacterial consortia and faecal bacterial communities obtained from healthy donors. [22][23][24][25][26][27] However, efficacy is often highly variable 18,[28][29][30] and a thorough understanding of the events that follow these interventions and mediate health-promoting effects is needed in order to fully exploit the potential benefits of microbiota manipulation strategies. [22][23][24][25][26][27] Whilst limitations in current knowledge of such mechanisms have largely hindered large-scale applications of diet supplementation and bacterial transfer to the management of helminth infections, several studies have investigated the efficacy of microbiome-targeting therapeutics-namely, pre-and probiotics-as means of controlling GI helminthiases of humans and farmed animals.…”

“…in ruminants, probiotics are thought to improve feed efficiency-for example, by enhancing nutrient absorption-and limit the onset of metabolic diseases. 23,24 Probiotics span a range of bacterial genera, and their functions include modulation of host immune responses, competition with pathogenic microorganisms (for both space and nutrients), and inhibition of bacterial toxin production. A myriad of mechanisms underpin these functions, and multiple modes of action through which probiotics may promote GI homeostasis and host health have been reported.…”

“…Administration of probiotic strains of the genera Lactobacillus, Lactiplantobacillus, Bacillus and/or Enterococcus has led to significant enhancement of host immunity against, and/or of reduced burdens of, Trichuris, Trichinella and Toxocara, as well as of blood flukes of the genus Schistosoma. 23,51 It is worth noting, however, that the majority of these studies were conducted in murine models of infection, and thus, administration of such probiotics to worm-infected humans and animal species of veterinary interest in 'real-world' scenarios might result in different outcomes. For instance, a 58% and 70% reduction in burdens of Trichinella spiralis adult worms and muscle larvae, respectively, was observed in mice supplemented with Lactobacillus casei ATCC 7469.…”

Antiparasitic Action of Lactobacillus casei ATCC 393 and Lactobacillus paracasei CNCM Strains in CD-1 Mice Experimentally Infected with Trichinella britovi

“…Recently, the interest in developing different anthelmintic treatments that are both efficacious and safe has been increasing. Particular attention has been given to the potential anti-parasitic effect of probiotics [ 10 ].…”