Case report: We present a case of a 33 year-old man with infective endocarditis who was transferred to our hospital for surgical treatment. He was known to have a "murmur" in childhood and was admitted with six-week history of progressive dyspnoea, orthopnea and rigors. On examination, he was afebrile, tachycardic and had late-systolic and diastolic murmurs, bibasal crackles and mild pitting oedema. Chest X-ray showed cardiomegaly and prominence of pulmonary vasculature. Transthoracic echocardiogram revealed a severely dilated left ventricle, a bicuspid aortic valve with a large vegetation attached to the right coronary cusp and severe aortic regurgitation. He was started on Gentamycin and Vancomycin and after discussion with the multidisciplinary team, scheduled for urgent aortic valve replacement. Perioperative transeosophageal echocardiography (TOE) revealed an additional small echogenic mass on the mitral valve (MV), at the level of postero-medial commissure, accompanied with moderate regurgitation and suggestive of MV infection. Inspection of the valve confirmed a small vegetation on A3 segment of anterior leaflet. Due to the severity of LV dysfunction, double valve replacement was not felt to be advisable, and therefore the aortic valve was replaced and aggressive MV debridement performed, followed by closure of a small perforation.
Early follow-up transthoracic echo revealed a dilated left ventricle with severely globally impaired systolic function and mild mitral regurgitation (MR) originating from posteromedial commissure. Antimicrobial therapy was escalated (addition of rifampicin and anti fungal treatment), however on day 5 he became pyrexial, and TOE showed MR originating from A3 suggestive of a perforation and evidence of new vegetation. Urgent surgical intervention was deemed necessary and the patient proceeded to mechanical MV replacement. Polymerase chain reaction (PRC) results from the native aortic valve identified the pathogen as Bartonella Quintana and antibiotics were changed accordingly to doxycycline and gentamicin. The patient made an uneventful recovery.
Discussion: This is a case of an aggressive culture-negative endocarditis caused by Bartonella Quintana, involving two native valves. Prevalence of culture-negative endocarditis ranges from 10-30% and Bartonella Quintana endocarditis is very uncommon in Western countries. PCR is vital in culture-negative infections to inform antimicrobial therapy and perioperative TOE (as well as post-operative TOE follow-up where concern exists) is key to inform surgical decision-making as well as check for complications/re-infection that may require further surgical intervention.