Probable zoonotic pulmonary prosthetic valve infective endocarditis and acalculous cholecystitis caused by Streptococcus equi subspecies zooepidemicus

Prosthetic pulmonary valve endocarditis is a rare but serious infective complication following correction of tetralogy of Fallot (ToF). We describe a probable zoonotic case of Streptococcus equi subspecies zooepidemicus prosthetic pulmonary valve infective endocarditis in a young woman with corrected ToF with regular exposure to horses. The case was further complicated by acalculous cholecystitis, which was the initial presenting syndrome, requiring laparoscopic cholecystectomy. Microbiological analysis of blood cultures yielded growth of S. equi with whole genome sequencing confirming the subspecies identification of zooepidemicus. The patient underwent successful combined medical and surgical management incorporating a 6-week course of intravenous antibiotics and a re-do homograft pulmonary valve replacement followed by prolonged oral antibiotic therapy. Clinicians should be mindful of the increased risk of endocarditis in adult congenital heart disease and relevant bacteraemia detection should prompt thorough valvular assessment.