Oral streptococci

Oral or viridizing streptococci form a substantial part of the normal flora of the oral cavity and upper respiratory tract. As the name suggests, we include streptococci in this group, which cause viridation (α-hemolysis) on the blood agar. Some γ-hemolytic species are also included. Streptococcus pneumoniae, which causes α-hemolysis, is discussed separately in the textbooks due to its importance in medicine.

Oral streptococci include: Streptococcus mutans, S. salivarius, S. milleri, S. sanguinis a S. mitis.

Diagnostic procedure

 * Material: sputum, blood, stool.
 * Identification:
 * microscopy: G+ cocci;
 * cultivation: BA (colony with α-hemolysis);
 * tests: negative optochin test, negative bile solubility test.

Disease
Oral streptococci are part of the normal flora of the oral cavity, upper respiratory tract, and digestive tract. They are among the conditioned pathogens. JTheir infection is preceded by another disease or infection. They can spread from the oral cavity to the body and cause bacteremia, meningitis, abscesses, pneumonia and (in contact with the endocardium) endocarditis. S. mutans affects the development of tooth decay.

Therapy
In the treatment of endocarditis, we administer high doses of antibiotics (eg. ampicilin).

related articles

 * Streptococcal infections: Group A streptococcal infections • Burns • Sore throat • Erysipelas • Impetigo • Infections caused by virulent streptococci • Complications and treatment od streptococcal infections • Rheumatic fever