Bacteremia describes a condition where bacteria enter the bloodstream. While the body typically contains many bacteria, their presence in the blood can lead to serious infections. Viridans streptococci are a common group of bacteria naturally found in the human body. Though usually harmless in their normal habitats, these bacteria can cause severe infections if they gain access to the bloodstream.
The Viridans Streptococci Bacteria
Viridans streptococci are a diverse collection of bacterial species, not a single type. They are Gram-positive bacteria, meaning they retain a purple stain in a specific laboratory test, and they often appear as small, round or oval cells in pairs or chains. These bacteria are characterized by their ability to cause alpha-hemolysis, which produces a greenish discoloration when grown on blood agar plates.
These bacteria predominantly reside in the human mouth and throat, forming a significant part of the normal oral flora. They are also found in the gastrointestinal and genitourinary tracts. They are considered opportunistic pathogens, meaning they can cause disease if they enter parts of the body where they don’t normally belong, such as the bloodstream.
How Strep Viridans Bacteremia Occurs
Bacteria from the viridans group can enter the bloodstream through various pathways, often related to breaches in the body’s protective barriers. Dental procedures, even routine cleanings or extractions, can allow these oral bacteria to enter the bloodstream. Poor dental hygiene, which can lead to gum inflammation or cuts in the mouth, also provides an entry point.
Beyond oral routes, gastrointestinal issues or medical device insertions, such as catheters, can also facilitate bacterial entry. Certain factors increase an individual’s susceptibility to viridans streptococci bacteremia. People with weakened immune systems, pre-existing heart valve conditions like prosthetic valves or congenital heart defects, or those who have recently undergone surgery are at higher risk.
Recognizing the Symptoms
The general signs and symptoms that may indicate strep viridans bacteremia can be non-specific, making them challenging to pinpoint. Individuals often experience fever and chills, which are common responses to systemic infection. Fatigue and a general feeling of being unwell, known as malaise, are also frequently reported.
Patients might also notice increased sweating, particularly at night. The severity and onset of these symptoms can vary widely among individuals, depending on factors such as the patient’s overall health and the extent of the infection. These symptoms can overlap with many other conditions, so medical evaluation is necessary for accurate diagnosis.
Diagnosis and Treatment Approaches
Diagnosing strep viridans bacteremia primarily involves identifying the specific bacteria in the bloodstream through blood cultures. Healthcare professionals collect blood samples and send them to a laboratory to grow and identify any present bacteria. If a patient has multiple positive blood cultures or exhibits signs of sepsis, it strongly suggests a clinically significant infection rather than contamination.
Further diagnostic tools may be employed depending on suspected complications. An echocardiogram, an ultrasound of the heart, may be used to check for heart involvement like infective endocarditis. Imaging techniques might also be utilized to detect abscesses or other localized infections.
Standard treatment for strep viridans bacteremia involves intravenous antibiotics. Identifying the specific strain of viridans streptococci and determining its sensitivity to various antibiotics guides the most effective treatment. While penicillin is often effective, some strains, particularly Streptococcus mitis, can exhibit resistance. The duration of antibiotic treatment can vary, often ranging from several days to weeks, and completing the entire course is necessary to eradicate the infection. In cases where complications like abscesses or severely damaged heart valves arise, surgical intervention may be required in addition to antibiotic therapy.
Potential Complications
One of the most frequent complications of strep viridans bacteremia is infective endocarditis (IE), an infection of the inner lining or valves of the heart. Viridans streptococci are a leading cause of this condition, particularly in individuals with pre-existing heart issues, such as damaged heart valves. IE involves damage to the heart valves, which can potentially lead to heart failure if left untreated.
Beyond infective endocarditis, other serious complications can arise. These include the formation of abscesses, which are collections of pus that can develop in various organs throughout the body. Septic emboli, which are infected clots that break off and travel through the bloodstream, can lodge in distant organs and cause new infections or blockages. Kidney damage is another potential outcome of severe or prolonged bacteremia. In some cases, viridans streptococcal bacteremia can even lead to more severe systemic responses like adult respiratory distress syndrome (ARDS) or septic shock, which can be life-threatening.