Entry 14
Probiotic science page
Produces bacteriocins and thrives in respiratory and food matrices, with potential for sinus microbiome applications.
Overview
Latilactobacillus sakei subsp. sakei 23K is a Gram-positive bacterium. It produces lactic acid plus other byproducts from sugar. It was first isolated from fermented meat products [1]. The complete genome of strain 23K (1.88 Mb) was one of the first lactobacillary genomes to be fully sequenced. This gave researchers basic insights into how lactic acid bacteria adapt to meat environments [1]. The strain is a model organism for studying bacteriocin (a bacteria-killing compound) production, cold tolerance, and food preservation [4]. In a landmark study, researchers found that L. sakei was depleted in people with chronic rhinosinusitis. It protected against the harmful bacterium Corynebacterium tuberculostearicum in a mouse sinus infection model [5]. In 2020, this species was moved to the new genus Latilactobacillus [7].
Mechanism
The genome of 23K carries metabolic pathways adapted to the meat environment. These include efficient use of nucleosides and arginine. It also has cold-shock proteins that let it grow at refrigeration temperatures [1]. A physical and genetic map was made before the genome was sequenced. This map provided the scaffold for later functional studies [2]. Comparing genomes across L. sakei strains reveals diversity in bacteriocin gene clusters and carbohydrate metabolism. This supports the rational design of starter culture combinations [3].
A key factor for survival is the ability to break down N-acetylneuraminic acid (NANA, sialic acid). This function relies on two newly described proteins (NanI and NanR). These let L. sakei use sialic acids from the host in the gut [6]. When it passes through the mouse gut, L. sakei survives for a short time. It turns different genes on or off depending on whether the mouse has a normal microbiome or is germ-free. This shows it responds to the surrounding microbial community [6].
In the sinus microbiome, L. sakei was identified as a potentially protective species. This was found by comparing the sinus microbiomes of chronic rhinosinusitis (CRS) patients with healthy people [5]. In a mouse model, L. sakei defended against C. tuberculostearicum sinus infection. It did this even when the sinus bacterial community was depleted. This shows a specific mechanism of fighting other bacteria [5].
Health Benefits
Chronic rhinosinusitis (observational + animal): Comparing sinus microbiomes showed that L. sakei is much lower in CRS patients than in healthy people. At the same time, C. tuberculostearicum levels go up. In a mouse model, L. sakei supplementation protected against C. tuberculostearicum-induced sinus infection [5]. (Evidence level: human observational + animal interventional)
GI transit survival (animal): L. sakei survives passage through the gut of both germ-free and normal mice. This proves it can reach and stay in the gut for a short time [6]. (Evidence level: animal model)
Biology
Genome: 1.88 Mb circular chromosome. It has genes for meat adaptation: nucleoside breakdown, the arginine deiminase pathway, and cold-shock proteins [1].
Genetic map: A physical and genetic map was made using pulsed-field gel electrophoresis. It located key metabolic and bacteriocin genes on the chromosome [2].
Comparative genomics: Strain-level diversity in bacteriocin clusters and sugar metabolism supports designing starter culture combinations [3].
GI fitness: NANA breakdown (NanI/NanR) gives a competitive edge in the host gut [6].
Taxonomy: L. sakei was reclassified as Latilactobacillus sakei in the 2020 reclassification [7].
Bibliography
[1] Chaillou S, et al. (2005). “The complete genome sequence of the meat-borne lactic acid bacterium Lactobacillus sakei 23K.” Nat Biotechnol. 23(12):1527–33. PMID: 16273110
[2] Dudez AM, et al. (2002). “Physical and genetic map of the Lactobacillus sakei 23K chromosome.” Microbiology (Reading). 148(Pt 2):421–431. PMID: 11832506
[3] Eisenbach L, Geissler AJ, Ehrmann MA, Vogel RF. (2019). “Comparative genomics of Lactobacillus sakei supports the development of starter strain combinations.” Microbiol Res. 221:1–9. PMID: 30825936
[4] Yu L, et al. (2024). “Latilactobacillus sakei: a candidate probiotic with a key role in food fermentations and health promotion.” Crit Rev Food Sci Nutr. 64(4):978–995. PMID: 35997270
[5] Abreu NA, et al. (2012). “Sinus microbiome diversity depletion and Corynebacterium tuberculostearicum enrichment mediates rhinosinusitis.” Sci Transl Med. 4(151):151ra124. PMID: 22972842
[6] Chiaramonte F, Blugeon S, Chaillou S, Langella P, Zagorec M. (2009). “Behavior of the meat-borne bacterium Lactobacillus sakei during its transit through the gastrointestinal tracts of axenic and conventional mice.” Appl Environ Microbiol. 75(13):4498–505. PMID: 19447958
[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
L. sakei 23K is mainly a research and reference strain. It is held in ATCC and KCTC culture collections. L. sakei is widely used as a protective starter culture in fermented meat products such as European sausage. It is also being studied as a candidate probiotic for respiratory and gut uses [4]. Specific consumer probiotic products containing L. sakei are limited but exist in some markets.