Lactobacillus alimentarius: Difference between revisions
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=7. Pathology= | =7. Pathology= | ||
''L. alimentarius'' has a very limited pathogenic potential and the research on this topic is limited. | |||
Many species of the ''Lactobacilli'' genus are considered to have beneficial effects on human health, often used in probiotics; however, occasionally they can cause infections, including endocarditis, bacteremia, neonatal meningitis, dental caries, pleuropneumonia, and intra-abdominal abscesses (18). Serious infections due to ''Lactobacilli'', such as primary bacteremia and endocarditis, have been observed in elderly individuals and immunocompromised patients, particularly those who have undergone organ transplantation (19). Endocarditis stands out as the most prevalent clinical condition associated with these infections and poses a significant risk to mortality rates (19). Other infections associated with ''Lactobacilli'' include intra-abdominal abscesses, meningitis, oral infections, conjunctivitis, bacteremia, and pleuropneumonia (19). | |||
=8. Current Research= | =8. Current Research= | ||
Include information about how this microbe (or related microbes) are currently being studied and for what purpose | Include information about how this microbe (or related microbes) are currently being studied and for what purpose | ||
Revision as of 14:45, 11 December 2023
1. Classification
a. Higher order taxa
Bacteria; Bacillota; Bacilli; Lactobacillales; Lactobacillaceae (1)
Species
Companilactobacillus (1)
2. Description and significance
Companilactobacillus alimentarius (also known as Lactobacillus alimentarius) is a lactic acid bacteria, which belongs to the family Lactobacillaceae. They are one of the most abundant groups of bacteria that are associated with humans, due to their use in fermentation to improve the taste and texture of food products. L. Alimentarius was discovered during an investigation on fish products, where it was identified as a spoilage organism in marinated herring (2). Although details relating to the genome and metabolism of L. alimentarius are unknown, it possesses a wide range of antimicrobial capabilities against Gram-positive and Gram-negative food-borne pathogens and several yeasts (3). Its heat-resistant properties and ability to withstand a broad range of pH allow it to be used as a natural food preservative, particularly for meats and dairy products (3). L. alimentarius is predominantly used in food spoilage prevention and safety in the food production industry.
3. Genome structure
The full genome of L. alimentarius is 2.34 Mbp, and the percent G+C content of DNA is 35.4%. (4). L. alimentarius has nine “signature genes” that are unique to the lineage, but they have not been described in detail (4). 213 strains of Lactobacilli have had their genomes analyzed: among these, the core genome consists of 73 genes, with the majority of them responsible for encoding essential proteins that are necessary for cell growth and replication (5). Lactobacilli also exhibit genes and molecules that support their probiotic function (7) Specifically, they encode genes involved in carbohydrate and protein metabolism, adherence mechanisms, and bacteriocin secretion (7). A large majority of the genome consists of a variety of phage and plasmid sequences. (5).
4. Cell structure/Morphology
L. alimentarius are Gram-positive, motile, and non-spore-forming, bacilli (8)(6). The length of L. alimentarius is dependent on the growth environment. The presence of citric acid, gluconic acid, or their combination promotes cellular elongation of L. alimentarius, but the bacterium does not show cellular elongation in the presence of NaCl (salt) (9), suggesting two different adaptation mechanisms by which cells respond to these substances (9). The cell wall of Lactobacilli consists of a thick, 20-100 nm, multi-layered peptidoglycan layer with teichoic acids, S-layer proteins, and other types of cell surface proteins that aid in structural integrity and protection (7).
5. Metabolic processes
L. Alimentarius are facultative hetero-fermentative bacteria (9) that ferment glucose and produce lactic acid, ethanol, and carbon dioxide as major byproducts (11). Growth of L. alimentarius occurs between 15°C and 37°C, and pentoses, hexoses, and disaccharides are primarily used as carbon sources (4). L. alimentarius can produce high concentrations of lactic acid in food products to reduce the pH enough to cause an antibacterial effect (12). L. Alimentarius contains many probiotic properties such as nitrite degradation, cholesterol removal, and antioxidant activity (13). The species within the genus Lactobacillus are predominantly oxygen-tolerant anaerobes, yet several strains can use oxygen in flavin oxidase-mediated reactions (14). Lactobacilli can degrade indigestible polysaccharides and protein, catabolize amines, and transform undesirable food ingredients into flavor substances (15). These flavor substances include organic acids, alcohols, ketones, and esters, which depend on the metabolic pathways (15). In the manufacturing of fermented foods and flavor development, the three main metabolic processes Lactobacilli partake in include glycolysis (sugar degradation), proteolysis (protein degradation), and lipolysis (fat degradation).
6. Ecology
L. alimentarius is mostly found in nutrient-rich habitats (16), such as fermented or spoiled foods and animal feed. Animal feed includes the body of invertebrate and vertebrate animals, as well as the surface of plants and soil. L. alimentarius is restricted by specific growth conditions, such as temperature and pH. Optimal growth temperatures range from 30-40 degrees Celsius and optimal pH ranges from 5.5-6.2 (8). Species of the Lactobacillus genus have been found throughout human bodies, specifically in the mouth, gastrointestinal tract, and female genital tract (17). However, existing research has not provided evidence that L. alimentarius inhabits the human body.
7. Pathology
L. alimentarius has a very limited pathogenic potential and the research on this topic is limited. Many species of the Lactobacilli genus are considered to have beneficial effects on human health, often used in probiotics; however, occasionally they can cause infections, including endocarditis, bacteremia, neonatal meningitis, dental caries, pleuropneumonia, and intra-abdominal abscesses (18). Serious infections due to Lactobacilli, such as primary bacteremia and endocarditis, have been observed in elderly individuals and immunocompromised patients, particularly those who have undergone organ transplantation (19). Endocarditis stands out as the most prevalent clinical condition associated with these infections and poses a significant risk to mortality rates (19). Other infections associated with Lactobacilli include intra-abdominal abscesses, meningitis, oral infections, conjunctivitis, bacteremia, and pleuropneumonia (19).
8. Current Research
Include information about how this microbe (or related microbes) are currently being studied and for what purpose
9. References
It is required that you add at least five primary research articles (in same format as the sample reference below) that corresponds to the info that you added to this page. [Sample reference] Faller, A., and Schleifer, K. "Modified Oxidase and Benzidine Tests for Separation of Staphylococci from Micrococci". Journal of Clinical Microbiology. 1981. Volume 13. p. 1031-1035.
