Pathogenic and Non-pathogenic Organisms
Similarities in both organisms include the fact that both organisms are non-sporulating. Although, not the only metabolite, Salmonella enterica can produce lactate as one of its metabolite while Lactococcus lactis produces lactate. Both organisms are anaerobes, feeding by fermenting substrates (PHAC, 2010). Salmonella enterica ferments glucose while Lactococcus lactis ferments milk.
Salmonella enterica is different from Lactococcus enterica in several ways. From gram staining, Salmonella enterica is a gram-positive organism while Lactococcus lactis is a gram-negative organism. At the level of feeding, Salmonella enterica feeds on a wide range of carbohydrates (PHAC, 2010). It is a heterofermentative organism whereas Lactococcus lactis is a homofermentative organism, fermenting lactose to produce lactic acid. Another difference is the fact that Lactococcus has a plasmid DNA while Salmonella enterica does not.
Lactococcus lactis is widely used for the production of dairy products. It is used in the production of yogurt and cheese (Todar. 2012). When the bacterium is added to milk, lactose is converted to lactic acid, and ATP is produced in the process, serving as the source of energy for the bacteria. In recent years, Lactococcus lactis has emerged as a potential delivery vector for immunomodulatory products for the treatment of inflammatory bowel disease. Inflammatory bowel disease is a gaining more prominence in the developed countries especially Europe and North America (Bahey-El-Din, 2010). Traditional modes of treating the disease make use of anti-inflammatory and immunosuppresive drugs. However, these drugs have side effects. The development of genetically engineered Lactococcus lactis to deliver human interleukin 10 to the gastrointestinal system of patients is proving to be very effective. In this way, this immunomodulator can be administered to the patient and it acts directly on the mucosa of the gastrointestinal system without side effects (Bahey-El-Din, 2010). The Lactococcus lactis is also administered orally to avoid systemic toxicity. Another substance, Tumor necrosis factor, can also be delivered to the gastrointestinal system of patients with inflammatory bowel disease. As the delivery is also oral, systemic toxicity is also not an issue (Bahey-El-Din, 2010).
Nisin, an antibiotic-like material is produced by Lactococcus lactis. The material has natural antimicrobial activity and it has been shown to be active against many gram-positive bacteria. These pathogens include Listeria, Staphylococcus and Clostridium. Nisin attacks the cell membrane of these bacteria. Nisin, unlike many other antibiotics, does not need a receptor to attach to before it interacts with the cell membrane. To this end, this substance is used as a food preservative in the food and beverage industry. It is used as a preservative in the dairy industry, to preserve cheese. Nisin has also been added to canned vegetables to preserve it. (Todar. 2012). The bacteria can also be genetically engineered to produce proteins, which give it a prominent role in the production of vaccines. Lactococcus also has an application in the development of system for delivery of vaccines. Lactococcus lactis may be genetically engineered to produce proteins from pathogenic organisms, which would act as antigens to trigger an immune response in humans. An example is in the development of a vaccine against streptococcus pyogens, which causes sore throat (Buccato et al, 2006). Lactococcus lactis may be genetically engineered to produce the preservation portion of the M protein contained in streptococcus, which allows it to adhere and colonize the mucosa of the throat. This leads to the development of immunity against streptococcus and thereby preventing sore throat. (Buccato et al, 2006).
REFERENCES
Kenneth, Todar (2012). Lactococcus lactis: nominated as the Wisconsin State Microbe. In, Todar's Online Textbook of Bacteriology. <http://www.textbookofbacteriology.net/featured_microbe.html>
Salmonella enterica spp: Pathogen Safety Data Sheet - Infectious Substances. Public Health Agency of Canada. <http://www.phac-aspc.gc.ca/lab-bio/res/psds-ftss/salmonella-ent-eng.php>
Scilla, Buccato et al (2006). Use of Lactococcus lactis Expressing Pilli from Group B Streptococcus as a Broad-Coverage Vaccine against Streptococcal Disease. The Journal of Infectious Diseases. Volume 194, Issue 3Pp. 331-340. <http://jid.oxfordjournals.org/content/194/3/331.short>
Mohammed, Bahey-El-Din (2010). Lactococcus lactis: From the Dairy Industry to Antigen and Therapeutic Protein Delivery. Discovery Medicine. <http://www.discoverymedicine.com/Mohammed-Bahey-El-Din/2010/05/15/lactococcus-lactis-from-the-dairy-industry-to-antigen-and-therapeutic-protein-delivery/>
