Q Fever Endocarditis on Porcine Bioprosthetic Valves

Abstract

Three patients developed Q fever endocarditis on porcine bioprosthetic valves. They had a subacute or chronic course with nonspecific symptoms, enlargement of the liver and spleen, and cardiac failure due to destruction of the cusps, without disruption of the valve ring. High-phase I-specific IgG and IgA antibody titers against Coxiella burnetii were found. C. burnetii was isolated in each patient by inoculating suspensions of valve tissue into a human fetal diploid fibroblast cell line, which was grown as monolayers on slides contained inside rubber-stoppered tube cultures. Patients were treated successfully with doxycycline, cotrimoxazole, and valve replacement and were followed up for periods of 24 to 42 months; no evidence of deterioration was found. The human fetal diploid cell culture may be an expeditious, easy, and safe method to isolate C. burnetii from cardiac valves. Valve replacement seemed necessary to cure prosthetic-valve endocarditis due to C. burnetii infection. Combined therapy with doxycycline and cotrimoxazole may control the disease and prevent reinfection of the homografts replacing the valves.

Comparison of different antibiotic regimens for therapy of 32 cases of Q fever endocarditis

“…Results obtained with combinations including co-trimoxazole are still controversial. Reports (6,7,9,29,34) show that nine patients required valve replacement, since viable C. burnetii were recovered from six patients after therapies of various durations. In our study, one patient was treated with cotrimoxazole combined with doxycycline and died 30 months after initiation of therapy.…”

Q fever

“…In acute infection, tetracycline shortens the duration of fever by about 50% when the drug is administered within the first 3 days of illness (67), and it remains the drug usually recommended in this setting (4). Cases of endocarditis have been treated with tetracyclines (26,79) or tetracyclines combined with sulfamethoxazoletrimethoprim (27,31,76). A more recent paper described treatment with doxycycline alone and doxycycline combined with rifampin, a quinolone, or sulfamethoxazole-trimethoprim.…”

“…The best-described chronic entity with C. bumetii is endocarditis (26,27,31,39,73,74,79). Symptoms begin gradually as long as 1 to 20 years after initial infection.…”

“…Prosthetic valves have shown little or no evidence of infection in the valve ring. Instead, vegetation formation and a mild to moderate inflammatory response in infected bioprosthetic valve material or on the surfaces of mechanical valves have been found (27,31).…”

“…Most cases involve the aortic or mitral valve in patients with preexisting valvular disease or prosthetic valves (27,31,39,73,74,79), but occasionally cases involve previously normal valves (26). Infection is a very indolent process, since many of the cases described have occurred many years after apparent exposure to C. bumetii.…”