Presenter of 2 Presentations
THE ROLE OF ORAL STREPTOCOCCI IN THE PATHOGENESIS OF ACUTE ISCHEMIC STROKE
THE ROLE OF ORAL STREPTOCOCCI IN THE PATHOGENESIS OF ACUTE ISCHEMIC STROKE
Abstract
Background and Aims
Acute ischemic stroke may be due to embolism from atherosclerotic carotid arteries. DNA of oral and gastrointestinal tract bacteria, mainly viridans streptococci group, have been detected in thrombus aspirates of ischemic stroke patients as well as in carotid endarterectomy samples. Viridans streptococci are known to possess thrombogenic properties. We studied whether the presence of viridans streptococci group bacteria can be confirmed in thrombus aspirates and in carotid artery specimens using bacterial immunohistochemistry.
Methods
Thrombus aspirates from 46 ischemic stroke patients (63.0 % male; mean age, 66.5 years) treated with mechanical thrombectomy as well as 48 carotid artery samples (62.5 % male; mean age, 66.4 years) from Tampere Sudden Death Study (TSDS), representing a cross section from the population, were immunostained with an in-house antibody cocktail against three species of viridans streptococci. Control samples with reference bacteria as well as liver and gut samples from the TSDS cases were stained to show the specificity of the antibody cocktail.
Results
Of the thrombus aspirate samples 39 (84.8 %) were clearly and strongly positive for viridans streptococci group bacteria. Most streptococci were detected inside neutrophil granulocytes, but there were also remnants of bacterial biofilm as well as free bacterial infiltrates in some samples. Of the carotid artery samples considerably less, 8 (16.7 %) were clearly immunopositive.
Conclusions
We confirmed that streptococci can be found in aspirated thrombi of acute ischemic stroke patients as well as in carotid artery samples. Our results suggest that viridans streptococci group bacteria play an important role in the pathogenesis of ischemic stroke.