Entry 13
Probiotic science page
Produces bacteriocin ABP-118 to inhibit pathogens and modulate mucosal immunity, with IBD model evidence.
Overview
Ligilactobacillus salivarius UCC118 is a well-studied probiotic strain. It was first isolated from the ileal-caecal region of the human gut [2]. It was one of the first probiotic lactobacilli to have its complete genome sequenced. The genome revealed a multireplicon architecture. This means the genetic material is split across multiple pieces: a 2.13 Mb chromosome, two small plasmids, and a 242 kb megaplasmid [1]. The strain stands out because it produces a broad-spectrum bacteriocin (a bacteria-killing compound) called Abp118. This compound helps it fight infections [2]. UCC118 has been tested in human clinical trials for gut barrier function. It has also been tested in animal models of inflammatory bowel disease [5,6]. In 2020, the genus Lactobacillus was reclassified. This species was moved to the new genus Ligilactobacillus [7].
Mechanism
UCC118 produces Abp118, a Class IIb two-peptide bacteriocin (a bacteria-killing compound). It has two parts: Abp118α provides the main antimicrobial punch. Abp118β boosts that activity [2]. The genetic region that encodes Abp118 includes an immunity gene (abpIM), an inducing peptide (AbpIP) for quorum sensing (bacteria communicating by chemical signals), and dedicated secretion machinery [2]. This bacteriocin inhibits a range of Gram-positive pathogens. It was the first bacteriocin from a known human probiotic to be characterized at the genetic level [2].
UCC118 also sticks to cells lining the gut. It changes how those cells respond at the gene level. Bacteriocin production shapes this interaction. This suggests that blocking pathogens at the gut surface is linked to signals the strain sends to the host [3,4]. In a human trial, UCC118 remodeled the gut microbiome. It changed the abundance of 99 types of bacteria across six major groups [5]. In a mouse model of colitis, the strain encouraged anti-inflammatory immune cells called macrophages to develop. Specifically, it increased IL-10 and M2 markers. It also sped up recovery of the gut microbial community [6].
Health Benefits
Human RCT (GI permeability): A randomized, double-blind, placebo-controlled crossover study enrolled 7 healthy adults. Participants took UCC118 daily for 4 weeks. The treatment reduced exercise-induced gut permeability. This was measured by sucrose recovery (P<0.05). It also remodeled the fecal microbiome [5]. (Evidence level: human RCT, small sample)
Murine colitis model: In DSS-induced colitis, UCC118 reduced disease severity in early stages when given before illness started. When given as treatment, it sped up resolution of inflammation. This was accompanied by increased tissue IL-10 and macrophage M2 markers [6]. (Evidence level: animal model)
Biology
Genome: Multireplicon architecture: 2.13 Mb chromosome, plus pMP118 megaplasmid (242 kb), plus pSF118-20 (20 kb), plus pSF118-44 (44 kb) [1]. The megaplasmid carries functions that may be involved in host interaction. These include bile salt hydrolase and cell-surface proteins [1].
Isolation source: Human ileal-caecal region [2].
Bacteriocin diversity: Subspecies-level analysis shows that bacteriocin production is common but varies among intestinal L. salivarius strains [3].
Taxonomy: Zheng et al. (2020) split the genus Lactobacillus into 25 genera. L. salivarius was reclassified as Ligilactobacillus salivarius [7]. The old name Lactobacillus salivarius is still widely used in clinical literature.
Bibliography
[1] Claesson MJ, et al. (2006). “Multireplicon genome architecture of Lactobacillus salivarius.” Proc Natl Acad Sci U S A. 103(17):6718–23. PMID: 16617113
[2] Flynn S, van Sinderen D, Thornton GM, Holo H, Nes IF, Collins JK. (2002). “Characterization of the genetic locus responsible for the production of ABP-118, a novel bacteriocin produced by the probiotic bacterium Lactobacillus salivarius subsp. salivarius UCC118.” Microbiology (Reading). 148(Pt 4):973–984. PMID: 11932444
[3] O’Shea EF, et al. (2012). “Subspecies diversity in bacteriocin production by intestinal Lactobacillus salivarius strains.” Gut Microbes. 3(5):468–73. PMID: 22892690
[4] O’Callaghan J, Buttó LF, MacSharry J, Nally K, O’Toole PW. (2012). “Influence of adhesion and bacteriocin production by Lactobacillus salivarius on the intestinal epithelial cell transcriptional response.” Appl Environ Microbiol. 78(15):5196–203. PMID: 22610429
[5] Axelrod CL, et al. (2019). “UCC118 supplementation reduces exercise-induced gastrointestinal permeability and remodels the gut microbiome in healthy humans.” Physiol Rep. 7(22):e14276. PMID: 31758610
[6] Iyer N, et al. (2022). “Lactobacillus salivarius UCC118™ Dampens Inflammation and Promotes Microbiota Recovery to Provide Therapeutic Benefit in a DSS-Induced Colitis Model.” Microorganisms. 10(7). PMID: 35889102
[7] Zheng J, et al. (2020). “A taxonomic note on the genus Lactobacillus: Description of 23 novel genera, emended description of the genus Lactobacillus Beijerinck 1901, and union of Lactobacillaceae and Leuconostocaceae.” Int J Syst Evol Microbiol. 70(4):2782–2858. PMID: 32293557
Available Products
UCC118 is mainly a research strain. It was developed at APC Microbiome Ireland (University College Cork). It has been used in clinical trials but is not widely sold as a consumer product. It is available from culture collections for research.