Streptococcus Viridans

INTRODUCTION:

• Commensal streptococcal bacteria species
• Either α-hemolytic or nonhemolytic. 

CULTURE CHARATERSTICS

• On blood agar, after incubation for 18 hrs
• Colonies  are small, dome shaped and glistening with an area of green discoloration (alpha hemolysis) around them

NORMAL INHABITANT OF

• The mouth
• The upper respiratory tract
• The gastrointestinal system
• The genitourinary tract
• On occasion, they can be found on our skin .

 INFECTION

• Harm people with compromised immune systems.
• Endocarditis
• Shock
• Intra-abdominal infection, or infection within the abdomen.
• Meningitis
• Pneumonia
• Cause transient bacteremia following tooth extraction or other dental procedures
• Get implanted on damaged or prosthetic valves or in a congenitally diseased heart, and grow to form vegetations.
• Str. mutans is important in causation of dental caries.
• Community acquired native valve endocarditis (Staphylococcus aureus ,most common and other includes Str viridans, Str bovis, other non group A Streptococci)
• Viridans streptococci  part of a mixed flora,from sites of sinusitis, brain abscess and liver abscess.
• Bacteremia occurs frequently in neutropenic patients, after bone marrow transplantation or high dose chemotherapy for cancer.

TREATMENT:

1. Bacteremia in neutropenic patients → Vancomycin.
2. Other infection → Penicillin.