Quantification of Multiple Bacteria in Calcified Structural Valvular Heart Disease

Area of Science:

• Cardiovascular Research
• Infectious Diseases
• Molecular Biology

Background:

• Structural valvular heart disease (sVHD) and acute infective endocarditis (aIE) are associated with polymicrobial infections in heart valve tissue (HVT).
• Distinguishing chronic bacterial presence in sVHD from acute aIE is clinically important.

Purpose of the Study:

• To quantify bacterial DNA in HVT of sVHD patients compared to aIE patients.
• To evaluate bacterial DNA concentration as a potential marker to differentiate chronic and acute infections.

Main Methods:

• DNA isolation from HVT of 100 sVHD patients and 23 aIE patients.
• Quantification of specific bacterial pathogens using TaqMan-qPCR.
• Investigation of polymicrobial infiltration using immunohistologic methods.

Main Results:

• A majority of sVHD patients (94%) tested positive for bacteria; 29% showed polymicrobial infections.
• Common pathogens in sVHD included Cutibacterium acnes, Enterococcus faecalis, and Staphylococcus aureus.
• Significantly lower DNA concentrations of E. faecalis and S. aureus were found in sVHD compared to aIE patients.

Conclusions:

• sVHD is frequently associated with bacterial infection and infiltration of HVT.
• TaqMan-qPCR is effective for detecting bacteria in HVT and discriminating between sVHD and aIE for specific pathogens like E. faecalis and S. aureus.