Q fever endocarditis in Spain. Clinical characteristics and outcome

Abstract

To describe the clinical presentation of a large number of Q fever endocarditis (QFE) and its management considering the role of serology. Eighty-three patients with definite QFE (56 native and 27 prosthetic valve) with a long-term follow-up after stopping treatment (median: 48 months) were included. Final outcome (cure or relapse) was compared according with the serological titre at the end of therapy: less than 1:400 of phase I Ig G antibodies by indirect immunofluorescence (group 1, N=23) or more than 1:400 (group 2, N=30). Eleven patients (13.2%) died from QFE and other 8 died for other reasons not related to endocarditis during follow-up. Surgery was performed in 61 (73.5%) patients and combined antimicrobial treatment was long (median: 23 months, IQR: 12 - 36). Seven relapses were observed, but five of them had received an initial incomplete antibiotic regimen. In patients who completed the programmed treatment (range: 12 - 89 months), serological titres at the end of therapy were not useful for predicting the final outcome: one relapse in each group. QFE requires a prolonged antimicrobial treatment, but serological titres are not useful for determining its duration.