Functional and Genomic Characterization of Ligilactobacillus salivarius TUCO-L2 Isolated From Lama glama Milk: A Promising Immunobiotic Strain to Combat Infections

Abstract

Potential probiotic or immunobiotic effects of lactic acid bacteria (LAB) isolated from the milk of the South American camelid llama (Lama glama) have not been reported in published studies. The aim of the present work was to isolate beneficial LAB from llama milk that can be used as potential probiotics active against bacterial pathogens. LAB strains were isolated from llama milk samples. In vitro functional characterization of the strains was performed by evaluating the resistance against gastrointestinal conditions and inhibition of the pathogen growth. Additionally, the adhesive and immunomodulatory properties of the strains were assessed. The functional studies were complemented with a comparative genomic evaluation and in vivo studies in mice. Ligilactobacillus salivarius TUCO-L2 showed enhanced probiotic/immunobiotic potential compared to that of other tested strains. The TUCO-L2 strain was resistant to pH and high bile salt concentrations and demonstrated antimicrobial activity against Gram-negative intestinal pathogens and adhesion to mucins and epithelial cells. L. salivarius TUCO-L2 modulated the innate immune response triggered by Toll-like receptor (TLR)-4 activation in intestinal epithelial cells. This effect involved differential regulation of the expression of inflammatory cytokines and chemokines mediated by the modulation of the negative regulators of the TLR signaling pathway. Moreover, the TUCO-L2 strain enhanced the resistance of mice to Salmonella infection. This is the first report on the isolation and characterization of a potential probiotic/immunobiotic strain from llama milk. The in vitro, in vivo, and in silico investigation performed in this study reveals several research directions that are needed to characterize the TUCO-L2 strain in detail to position this strain as a probiotic or immunobiotic that can be used against infections in humans or animals, including llama.

Probiotic Characteristics of Ligilactobacillus salivarius AS22 Isolated from Sheep Dung and Its Application in Corn-Fox Tail Millet Silage

“…The acid tolerance potential of bacteria was mainly based on the outer membrane properties in stress conditions. The isolate AS22 showed high acid tolerance potential at low pH which was significantly concurrent with Vega et al, results, that stated as Lactobacillus salivarius TUCO-L2 had significant resistance to low pH and high bile salts concentrations [30]. Among the isolated bacterial strains, AS22 showed higher resistance properties in bile salt condition than the other isolates.…”

Research Development on Anti-Microbial and Antioxidant Properties of Camel Milk and Its Role as an Anti-Cancer and Anti-Hepatitis Agent

“…These genera have a key role against both the Gram-positive and Gram-negative bacteria and protect against multidrug-resistant Salmonella [ 28 ]. In addition, the LAB isolated from camel milk can be used as probiotics/immunobiotics [ 29 , 30 ], facilitating the host’s metabolism, controlling foodborne pathogens and reducing antibiotic resistance [ 31 , 32 , 33 ]. Few studies from Iran have reported the anti-pathogenic and probiotic properties of LAB isolated from the milk of one humped camel [ 34 , 35 ].…”

“…It is also worth noting that some of the LAB isolates are more effective than others. Furthermore, it has been reported that Ligilactobacillus salivarius ( L. salivarius) TUCO-L2 isolated from camel milk has stronger probiotic/immunobiotic properties compared to other LAB isolates [ 29 , 41 ]. Understanding the mechanisms by which the different LAB confer their effects will enable researchers to identify the most effective species that can be further developed as anti-microbial agents.…”

“…Quilodrán-Vega et al [ 29 ] demonstrated that L. salivarius TUCO-L2 is associated with resistance to pH and a higher concentration of bile salt showed anti-microbial activity against Gram-negative intestinal bacteria. The anti-microbial activity of L. salivarius TUCO-L2 was ascribed to its ability to elicit innate immune responses in the intestinal epithelial cells of mice triggered by Toll-like receptor (TLR)-4 activation.…”

“…The anti-microbial activity of L. salivarius TUCO-L2 was ascribed to its ability to elicit innate immune responses in the intestinal epithelial cells of mice triggered by Toll-like receptor (TLR)-4 activation. It has also been shown that L. salivarius TUCO-L2 regulates the chemokines and cytokines mediated by the modulation of the negative regulators of the TLR pathway [ 29 ]. Interestingly, oral supplementation of L. paracasei Pro4 and L. rhamnosus Pro7 in mice isolated from camel milk mediated the regulation of Toll-like receptor (TLR)-2, interferon (IFN)-g and secretory immunoglobulin A (IgA) to regulate the gut immunity of mice [ 42 ].…”