Bartonella endocarditis in patients with right ventricle-to-pulmonary artery conduit: 2 case reports and literature review

Bartonella quintana pulmonary native valve endocarditis

Bartonella quintana is a well-known cause of blood culture-negative endocarditis; however, pulmonary valve involvement is rare. The case of a 40-year-old African male who presented to the Emergency Department with chest pain, cardiac failure, and a 2-week history of fever is presented. Transoesophageal echocardiography confirmed an atrial septal defect, severe pulmonary insufficiency with large vegetations, severe mitral regurgitation due to anterior leaflet prolapse, and right ventricular dysfunction. Empirical antibiotic therapy was started, and urgent surgical intervention was decided. There were vegetations on the three pulmonary valve leaflets and the mitral valve. Closure of the atrial septal defect, mitral and tricuspid valve repair, pulmonary valve replacement with a biological prosthesis, and infundibuloplasty of the right ventricle were performed. The postoperative course was uneventful. Preoperative blood cultures were negative, and B. quintana was detected through 16S rRNA gene amplification and sequencing in mitral and pulmonary implants. Serology showed positive titers of 1/1260 for both B. quintana and B. henselae. Ceftriaxone and gentamicin were administered for 10 days, followed by oral doxycycline for 12 weeks. A one-year echocardiogram showed normal functioning of the pulmonary prosthesis and the mitral and tricuspid repair. Infection caused by B. quintana is a rare cause of endocarditis with negative blood cultures, and multivalvular and pulmonary valve involvement is exceptional.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12055-024-01727-4.

Case series of 12 Bartonella quintana endocarditis from the Southwest Indian Ocean

BACKGROUND

Bartonella spp. are fastidious bacteria frequently identified as the cause of blood culture-negative (BCN) endocarditis. However, Bartonella infections are difficult to diagnose in routine laboratory testing and their incidence is probably underestimated. We investigated the epidemiological and clinical features of Bartonella endocarditis cases diagnosed between 2009 and 2021 on Reunion Island (Southwest Indian Ocean).

METHOD

We retrospectively included all patients diagnosed with Bartonella endocarditis at Reunion Island University Hospital during this period. Endocarditis was diagnosed on the basis of microbiological findings, including serological tests (IFA) and PCR on cardiac valves, and the modified Duke criteria. We used then the multispacer typing (MST) method to genotype the available Bartonella strains.

FINDINGS

We report 12 cases of B. quintana endocarditis on Reunion Island (83.3% in men, median patient age: 32 years). All the patients originated from the Comoros archipelago. The traditional risk factors for B. quintana infection (homelessness, alcoholism, exposure to body lice) were absent in all but two of the patients, who reported head louse infestations in childhood. Previous heart disease leading to valve dysfunction was recorded in 50% of patients. All patients underwent cardiac valve surgery and antimicrobial therapy with a regimen including doxycycline. All patients presented high C-reactive protein concentrations, anemia and negative blood cultures. The titer of IgG antibodies against Bartonella sp. exceeded 1:800 in 42% of patients. Specific PCR on cardiac valves confirmed the diagnosis of B. quintana endocarditis in all patients. Genotyping by the MST method was performed on four strains detected in preserved excised valves and was contributive for three, which displayed the MST6 genotype.

CONCLUSIONS

Bartonella quintana is an important cause of infective endocarditis in the Comoros archipelago and should be suspected in patients with mitral valve dysfunction and BCN from this area.