Viridansstreptokokit

Viridans streptococci is a group of Gram-positive, facultative anaerobic bacteria that are part of the normal flora of the upper respiratory tract and oral cavity of humans. The name "viridans" comes from the Latin word "viridis," meaning green, a characteristic of the alpha-hemolytic reaction they often produce on blood agar. This means they partially lyse red blood cells, causing a greenish discoloration around the colonies. While generally harmless commensals, viridans streptococci can become opportunistic pathogens, particularly in individuals with compromised immune systems or certain underlying medical conditions. They are a common cause of subacute bacterial endocarditis, an infection of the heart valves, which can arise when bacteria enter the bloodstream, often after dental procedures or minor trauma to the mouth. Other infections associated with viridans streptococci include abscesses in various parts of the body, bacteremia, and pneumonia. Diagnosis typically involves culturing blood or infected tissue samples, followed by identification and susceptibility testing. Treatment usually involves antibiotics, with the specific choice depending on the identified species and the site of infection. Maintaining good oral hygiene is considered an important factor in preventing viridans streptococcal infections.