What is it about?
Heart valves can become infected (endocarditis), but could bacteria also live in valves without causing infection? We analysed 34 aortic and mitral valves removed during heart surgery from patients with no history or sign of infection, mostly for degeneration. Standard cultures grew nothing, but DNA sequencing (next-generation sequencing) detected bacterial DNA in 15 valves (44%). Escherichia coli was the most frequent. Bacterial DNA tended to be more common in calcified valves than in non-calcified ones, and E. coli was relatively more abundant in valves of diabetic patients, although these differences were not statistically significant in this small sample.
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Why is it important?
Finding bacterial DNA in apparently sterile, non-infected heart valves suggests that a valvular microbiome may exist. If confirmed, it could help explain links between microbes, valve calcification and metabolic diseases such as diabetes, and open new perspectives on how heart valve disease develops.
Perspectives
This study came from a simple question we asked with cardiac surgeons and molecular microbiologists in Trieste: are heart valves really sterile? The answer seems to be not always. I find the idea that bacteria may contribute silently to valve degeneration fascinating, and worth exploring in larger studies.
Professor Stefano Di Bella
Universita degli Studi di Trieste
Read the Original
This page is a summary of: Bacterial colonization of explanted non-endocarditis cardiac valves: evidence and characterization of the valvular microbiome, Interactive Cardiovascular and Thoracic Surgery, November 2020, Oxford University Press (OUP),
DOI: 10.1093/icvts/ivaa285.
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