Streptococcus viridans

Definition

Streptococcus viridans is a group of gram-positive, facultatively anaerobic bacteria that are commonly found in the normal flora of the human oral cavity, upper respiratory tract, and gastrointestinal tract. These bacteria are known for their ability to cause various infections, particularly in the circulatory and lymphatic systems.

5 Must Know Facts For Your Next Test

1. Streptococcus viridans is a common cause of infective endocarditis, an infection of the heart valves or lining.
2. These bacteria can enter the bloodstream during dental procedures or from poor oral hygiene, leading to bacteremia and potential seeding of the heart.
3. Streptococcus viridans infections are often associated with a subacute presentation, with gradual onset of symptoms like fever, fatigue, and heart murmurs.
4. Antibiotic prophylaxis is recommended for certain high-risk patients undergoing dental or other procedures to prevent Streptococcus viridans-related endocarditis.
5. Treatment for Streptococcus viridans infections typically involves a combination of antibiotics, and in severe cases, surgical intervention may be necessary.

Review Questions

• Explain how Streptococcus viridans can lead to infective endocarditis and the importance of preventive measures.
  • Streptococcus viridans is a common cause of infective endocarditis, an infection of the heart valves or lining. These bacteria can enter the bloodstream during dental procedures or from poor oral hygiene, leading to bacteremia. The bacteria can then seed and infect the heart, causing endocarditis. Antibiotic prophylaxis is recommended for certain high-risk patients undergoing dental or other procedures to prevent Streptococcus viridans-related endocarditis, as this condition can be life-threatening if left untreated.
• Describe the typical clinical presentation and treatment approach for Streptococcus viridans infections.
  • Streptococcus viridans infections are often associated with a subacute presentation, with gradual onset of symptoms like fever, fatigue, and heart murmurs. Treatment typically involves a combination of antibiotics, targeting the specific strain of Streptococcus viridans causing the infection. In severe cases, such as infective endocarditis, surgical intervention may be necessary to remove infected tissue or replace damaged heart valves. The goal of treatment is to eradicate the infection and prevent complications like heart failure or stroke.
• Analyze the role of the circulatory and lymphatic systems in the pathogenesis and dissemination of Streptococcus viridans infections.
  • Streptococcus viridans infections can have a significant impact on the circulatory and lymphatic systems. These bacteria can enter the bloodstream, leading to bacteremia, which allows the infection to disseminate and potentially seed the heart, causing infective endocarditis. The lymphatic system may also be involved, as it plays a role in the body's immune response to the infection. Additionally, the circulatory system can be affected by the complications of Streptococcus viridans infections, such as heart valve damage, heart failure, and the risk of embolism. Understanding the interplay between Streptococcus viridans and the circulatory and lymphatic systems is crucial for effective diagnosis, treatment, and prevention of these potentially life-threatening infections.

Related terms

Viridans Streptococci: A group of Streptococcus species that produce green (viridans) colonies on blood agar due to the partial hemolysis of red blood cells.

Endocarditis:

An infection of the inner lining of the heart (endocardium), often caused by Streptococcus viridans bacteria.

Bacteremia:

The presence of bacteria in the bloodstream, which can lead to serious infections like endocarditis when caused by Streptococcus viridans.