A case of prosthetic mitral valve endocarditis caused by Brucella abortus

Brucella Prosthetic Valve Endocarditis: A Systematic Review

Objective

Brucella prosthetic valve endocarditis is a rare but a life-threatening complication of brucellosis. It remains a diagnostic challenge. Optimal treatment of Brucella prosthetic valve endocarditis is debated. Available data is limited to case reports or small case series. The purpose of this study was to systematically review all published cases of Brucella prosthetic valve endocarditis in the literature.

Method

A systematic review of PubMed database, Google, Google Scholar, and Scopus (From January 1974 to the present) for studies providing epidemiological, clinical and microbiological data as well as data on treatment and outcomes of Brucella prosthetic valve endocarditis was performed.

Results

A total of 51 reported cases were reviewed. Brucella melitensis (45%) and Brucella abortus (11.7%) were the most frequently isolated species. Most common type of prosthesis valve was mechanical prothesis (84.3%) and ten patients had double valve prosthesis (19.6%). Fever and dyspnea were present in 100% and 37.2% of the cases, respectively. The diagnosis was set with echocardiographic finding in 30 cases (93.7%), which revealed vegetation in 27 cases (84.3%). Most used antibiotics were rifampicin, doxycycline and aminoglycoside or cotrimoxazole. No deaths were noted in patients treated by combined medical and surgical treatment, but mortality was noted in 27.7% of the cases treated by antibiotics alone (p = 0.006).

Conclusion

This systematic review highlights diagnostic challenges and demonstrates that surgery improved outcome by reducing mortality in patients treated with the combined surgical and medical treatment option. Brucellosis should be considered in the differential diagnosis of prosthetic valve endocarditis in patients residing in or traveling to areas of endemicity.

Medical versus medical and surgical treatment for brucella endocarditis

This review was undertaken to determine the role of surgery in the treatment of brucella endocarditis. All English and French articles reporting brucella endocarditis (1966 to 2011) in PubMed, Google, and Scopus were reviewed. In all, 308 cases were identified, and linear and logistic regression was performed. Surgery improved outcomes by decreasing mortality from 32.7% in the medical treatment only group to 6.7% in the combined surgical and medical treatment group (p<0.001). This association was still significant while controlling for other contributing factors. In the absence of a controlled trial, we recommend the utmost vigilance and consideration of surgical management in treating such patients.

Brucella endocarditis in prosthetic valves

Human brucellosis is a multiple organ disease that presents with fever and is most often transmitted via contaminated, unpasteurized goat milk and cheese. In chronic cases, focal complications (eg, spondylitis, neurobrucellosis and endocarditis) are frequently seen. Although the disease may be severely debilitating, the mortality rate is low. Fatal cases are often due to endocarditis. Because Brucella endocarditis is a rare complication (2% to 5%), therapeutic considerations are based on single-case experiences only. Therapy includes long-term antibiotic treatment using combinations of various antimicrobial drugs and surgical valve replacement when required. A case of Brucella endocarditis complicated by the infection of two valvular prostheses implanted after involvement of the mitral and aortic valve due to rheumatic fever is described. The patient was successfully treated by a medical and surgical approach. Therapeutic strategies in Brucella endocarditis are discussed in light of the current literature.

Brucella endocarditis complicated with a mycotic aneurysm of the superior mesenteric artery: a case report

Brucella endocarditis, although a rare complication of brucellosis, is the main cause of death attributable to this disease. Mycotic aneurysm is an important extracardiac complication of infective endocarditis. Mycotic aneurysm of the superior mesenteric artery is extremely rare. In the present case, we report a patient with Brucella melitensis endocarditis complicated with a superior mesenteric artery aneurysm. To our knowledge, this is the first such reported case.

A Case of Mitral Stenosis Complicated With Seronegative Brucella Endocarditis

Brucellosis is a multisystemic disease. The most common cause of death from the disease is endocarditis. The aortic valve is most commonly affected. The disease rarely involves the mitral valve. A 30 year-old woman presented with complaints of chills and fever up to 38 degrees C at night, fatigue, palpitations, and dyspnea for the previous 3 weeks. Cardiac auscultation revealed a diastolic murmur in the mitral area. Her temperature was 38.3 degrees C. On echocardiographic examination, the mitral valve area was 0.62 cm (2) and an isoechoic mass thought to be a vegetation was detected on the anterior mitral leaflet. A diagnosis of infective endocarditis was made and vancomycin administration was commenced. Brucella melitensis was isolated in all three blood samples, however, the patient remained seronegative with Brucella agglutination titers of up to 1/160. The antibiotic therapy was then shifted to doxycycline (200 mg/day), rifampicin (600 mg/day), and ciprofloxacin (1000 mg/day). After 30 days of treatment, surgery was performed for the severely stenotic mitral valve and to remove the vegetation. The operation was successful. The postoperative period was uneventful. On the follow-up she had no complaints. In cases with Brucella endocarditis, after diagnosis, antibiotic therapy must be started immediately and when the clinical condition improves, surgical intervention should be performed when indicated.

Brucellosis in immigrants in Denmark

Brucellosis is a rarely encountered infection in northern Europe. We report 4 cases of Brucella abortus bacteremia occurring in Denmark during 1999-2000. The clinical presentation was characteristically vague and brucellosis was not suspected by the attending physicians, partly because incomplete patient histories were obtained as a result of language barriers. The diagnosis was finally established by means of blood cultures, which were performed because of fever of unknown origin.

Is there a future for adsorption techniques in sepsis?

During sepsis toxins released from, e.g., bacteria induce reactions of various cascade systems that may cause progression of the patient into septic shock, disseminated intravascular coagulation, multiorgan dysfunction syndrome and subsequent death. The use of conventional treatments using antibiotics, fluid substitution, inotropic drugs, respiration aid and dialysis is not enough to reverse the serious prognosis. The addition of various other drugs such as antibodies against various cytokines and cytokine receptors, pentoxiphylline, immunoglobulins or high doses of steroids is usually without benefit for the prognosis of the patient. Another possibility to reduce the extent of toxins and other harmful compounds in the circulation is the use of apheresis (removal by technical devices). This can be done either in a nonselective way (plasma exchange, plasmapheresis) or more selectively using various adsorbers such as polymyxin B. The survival in studies varies between 50 and 80%. Besides the use of nonselective apheresis, the development of various selective adsorption techniques may be one approach to improve survival of these severely ill patients.