Are susceptibility to infective endocarditis and effectiveness of antibiotic prophylaxis linked to fluctuations of the immune system? A novel hypothesis

Pier Paolo Bassareo¹, Luisa Marras², Giuseppe Calcaterra³

¹University College of Dublin, Mater Misericordiae University Hospital and Our Lady’s Children’s Hospital Crumlin, Dublin, Republic of Ireland - ²Department of Medical Sciences and Public Health, University of Cagliari, Cagliari, Italy - ³University of Palermo, Palermo, Italy

Introduction: An amendment incorporated into the 2007 AHA and 2009 ESC guidelines on infective endocarditis led to a substantial restriction in indications for the administration of antibiotic prophylaxis. This may have resulted in a subsequent steady increase in the number of cases of infective endocarditis worldwide.

Methods: It has been hypothesised that susceptibility to infective endocarditis, together with effectiveness of antibiotic prophylaxis, may be linked to fluctuations of the immune system. Throughout a person’s lifetime, individual susceptibility to infective endocarditis may vary in an identical situation of risk.   As a consequence, a personalised targeted approach should be adopted when prescribing antibiotic prophylaxis to prevent onset of endocarditis, taking into account a series of factors including age, comorbidities, cortisol levels, and ethnicity. Children affected by bicuspid aortic valve and injection drug users are amongst the newly-emerging higher risk populations.

Conclusion: This up-to-dated narrative review summarizes all the available scientific evidence concerning the variable influence of the immune system on susceptibility to infective endocarditis.