![]() has been reported ( Fournier et al., 2001). More recently discovered, an increase in endocarditis due to the fastidious Bartonella spp. The most frequently reported of these are Coxiella burnetii, Brucella spp., Abiotrophia spp., HACEK group endocarditis and Listeria monocytogenes ( Brouqui & Raoult, 2001). Slow-growing and fastidious organisms represent approximately 5–15% of infective endocarditis and 50% of CNE. Another cause of CNE is subacute right side endocarditis and mural endocarditis ( Brouqui & Raoult, 2001). Antibiotic treatment preceded blood culture in 45–60% of cases of culture-negative endocarditis (CNE) ( Lamas & Eykyn, 2003 Werner et al., 2003a). However, with the use of modern diagnosis techniques that will be reviewed below, especially PCR and culture of infected valves, the number of cases without a detected aetiology dropped from 27% to 9% and 1.4% in the last published series ( Hoen & Alla, 2002 Lamas & Eykyn, 2003 Werner et al., 2003a Houpikian & Raoult, 2004). In a recent study, vegetation was detected in 87% and 75% of cases of Bartonella and Whipple's disease endocarditis, respectively, and in only 13% of Q fever cases ( Fenollar et al., 2001), while it was detected in 39% of positive blood culture endocarditis ( Watanakunakorn & Burkert, 1993). The sensitivity of echocardiography depends upon the causative organism, the operator and the quality of the echocardiograph. Its role in routine screening for endocarditis is controversial. ![]() Transeosophagal echocardiography is more invasive and expensive than transthoracic echocardiography but reportedly is more efficient in detecting smaller lesions. Echocardiography has assumed a central role in the diagnosis of suspected endocarditis. ![]() A new or changing murmur is detected in 40% of patients with endocarditis only ( Stamboulian & Carbone, 1997). Cardiac murmur is the second most frequent finding in endocarditis but may be absent in the initial stage of right side endocarditis. However, numerous situations in which blood culture or echocardiography are not able to confirm the diagnosis, lead to a high degree of suspicion of endocarditis.įever, the most common finding in endocarditis, may not be present in the elderly or in patients given antibiotic therapy before presentation, or in Whipple's disease ( Richardson et al., 2003) and it may be low-grade or intermittent in Q fever endocarditis ( Brouqui et al., 1993). The diagnosis is most often based upon the detection of vegetation on the cardiac valves using echocardiography and positive blood culture. Infective endocarditis can be evoked in a patient by fever and a new or changing cardiac murmur. However, the fact that DNA remnants of past endocarditis can be detected some time after the acute episode, when the patient has been cured, suggests that the predictive value of these techniques along with the traditional histology and culture need to be evaluated closely.Ĭulture-negative endocarditis, Bartonella sp, Coxiella burnetii, PCR, whipple's disease, HACEK Introduction This is especially true in the case of culture-negative endocarditis following earlier antibiotic therapy. During the past decade the use of molecular techniques such as PCR with subsequent sequencing to detect or to identify bacteria in valves from patients with infectious endocarditis have considerably improved the aetiological diagnosis. Although it was previously considered that the prevalence of such organisms was identical throughout the world, recent investigations on Bartonella endocarditis clearly showed that the aetiology of culture-negative endocarditis is likely to be strongly related to epidemiology of the agent in each country. Although in half of cases this is due to previous antibiotic therapy, in the other half, the aetiology of culture-negative endocarditis is intracellular bacteria such as Coxiella burnetii or fastidious growing bacteria. Sterile blood cultures are noted in one third of patients with infectious endocarditis.
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