Streptococcus salivarius is a Gram-positive, non-pathogenic bacterium naturally found in the oral microbiota of healthy individuals. It is recognized as an effective probiotic due to its antimicrobial properties and ability to stimulate the immune system, particularly activating natural killer (NK) cells and producing anti-tumor cytokines such as interferon-gamma and interleukin-12 (IL-12). Strains K12 and M18 of this bacterium are specifically used to combat harmful oral bacteria and prevent tooth decay. These strains act by producing bacteriocins, especially against Streptococcus mutans (the main cause of tooth decay). Probiotics, in general, are live microorganisms that, when consumed in sufficient amounts, have beneficial effects on the host's health. Streptococcus salivarius, as a probiotic, plays a role not only in oral and dental health but also in improving overall body health. Studies have shown that this bacterium can help reduce bad breath, improve gum health, and reduce dental plaque formation. Additionally, the use of products containing this probiotic, such as toothpaste and mouthwash, can help its effective colonization in the oral cavity. Compared to conventional methods such as the use of antibiotics, probiotics are safer and reduce the risk of microbial resistance. However, probiotic consumption may cause mild side effects such as bloating or diarrhea in some individuals. Overall, Streptococcus salivarius as a promising probiotic plays an important role in maintaining oral and dental health and improving the quality of life.
The Urtica dioica is a flowering plant with long history of use in folk medicine and as a food source. Nettles grow all over the world in mild to temperate climates. The study aimed to determine the antibacterial activity of alcoholic watery extracts of dry leaves of Urtica dioica on some pathogenic microorganisms (E.coli, Staphylococcus. aureus). The Plants were collected in the early time of January from Baghdad. Deride leaves of Uritica were extracted using co-solvent (Water and ethanol) extraction way by Soxhelt apparatus for crude extraction, and use rotary evaporator to obtain power extract. The series dilution was prepared 50%, 25, 12.5w/v that use on Mueller-Hinton agar plates against the St.aureus, E.coli by using well diffusion method then compared with antimicrobial activity of many antibiotics against the same isolates using Kirby-Bauer method. The crude extract of U. dioica showed significant antibacterial effect against some clinically important pathogenic bacteria Staph.aureus : at the concentration 50% the inhibition zone was 20 mm , followed by 25% (14mm) , and12.5%(10mm), and E.coli : at the concentration 50% the inhibition zone was18mm , followed by 25%(12mm) ,and 12.5(8mm) respectively. Based on the obtained results it can be concluded that U. dioica is useful as antibacterial agent in treating infectious diseases.