Diagnosis Of Culture-negative Endocarditis Research Articles

Role of procalcitonine, hsCRP and 16SrRNA in diagnosis of culture negative endocarditis

Infective endocarditis infects the heart's inner surface, mostly the valves. It is a lethal disease with a high rate of morbidity and fatality. It mostly caused by bacteria, but fungi can also cause it. Microbiological diagnosis relies on blood culture. Molecular and biochemical indicators add to diagnosis, particularly in culture-negative patients. This study aimed to decide the role of 16s rRNA, procalcitonin, and high sensitivity C reactive protein (hsCRP) in the diagnosis of culture negative infective endocarditis (CNIE) in Assiut university hospitals. This cross-sectional study included 60 patients who were admitted to cardiac hospitals with suspected infective endocarditis according to modified DUKE criteria. A group of 20 apparently healthy subjects served as a control group for investigation of inflammatory biomarkers. We performed blood culture, biochemical markers and molecular investigations. Of the 60 patients, there were 46 (76.7%) culture positives and 14 (23.3%) culture negatives. Staphylococcus aureus was the most prevalent pathogen in culture positive patients, followed by enterococcus and klebsiella. Linezolid and imipenem were the most sensitive antibiotics for Gram-positive and Gram-negative bacteria, respectively. Amplification of bacterial 16S rRNA gene, after DNA extraction from whole blood samples, was positive in 11/14 cases (78.5%) of culture negative patients and in 42/46 cases (91.3%) of culture positive patients. The range of procalcitonin in culture positive patients was (0.32- 89) ng/ml, significantly higher than in culture negative patients (0.02- 8.8) ng/ml, and in the control group (0.01-0.08) ng/ml. hsCRP showed the same pattern. In conclusion, our data suggest that PCR was the most accurate diagnostic tool for diagnosing CNIE, followed by procalcitonin, and hsCRP, respectively.

Prevalence of Bartonella sp. in United States military working dogs with infectious endocarditis: a retrospective case–control study

ObjectivesBartonella infection has been associated with endocarditis in humans, dogs, cats and cattle. In order to evaluate the importance of this pathogen as a possible source of endocarditis in United States military working dogs (MWDs), we performed a retrospective case–control study on 26 dogs with histological diagnosis of culture negative endocarditis (n = 18), endomyocarditis (n = 5) or endocardiosis (n = 3) and 28 control dogs without any histological cardiac lesions. MethodsDNA was extracted from paraffin embedded cardiac valves and tissues from case and control dogs and submitted to PCR testing with primers targeting the Bartonella gltA gene. PCR-RFLP using four restriction endonucleases and partial sequencing was then performed to determine the Bartonella species involved. ResultsNineteen (73%) cases were PCR positive for Bartonella, including B. henselae (8 dogs), B. vinsonii subsp. berkhoffii (6 dogs), B. washoensis (2 dogs) and B. elizabethae (1 dog). Only one control dog was weakly PCR positive for Bartonella. Based on the type of histological diagnosis, 13 (72.2%) dogs with endocarditis, 3 (60%) dogs with endomyocarditis and all 3 dogs with endocardiosis were Bartonella PCR positive. ConclusionsBartonella sp. Infections were correlated with cardiopathies in US military working dogs. Systemic use of insecticides against ectoparasites and regular testing of MWDs for Bartonella infection seem highly appropriate to prevent such life-threatening exposures.

PO.13 Infective endocarditis presenting with lymphocytic meningitis

A 64-year-old lady presented with an acute onset febrile illness followed by a seizure and subsequent confusion. Examination revealed a vasculitic rash but no focal neurological deficits. She was noted...

16S-ribosomal DNA to diagnose culture-negative endocarditis

Culture-negative endocarditis (CNE) accounts for 2.5% to 48% of all cases of infectious endocarditis (IE). Prior or concurrent antibiotic treatment at the time blood cultures are taken accounts for 45% to 60% cases of CNE; the remainder are caused by slow-growing and fastidious organisms. Although limited in sensitivity because of potential contaminating bacterial DNA, detection of bacterial 16S ribosomal (r) DNA (from the 16S rRNA gene) is nevertheless more sensitive than culture. It is accomplished by using polymerase chain reaction (PCR) that targets highly conserved regions of the 16S rRNA gene. The identity of noncultivated infecting agents can then be determined by sequencing PCR products and comparing them with known 16S rDNA sequences from a wide range of bacteria. This has served to broaden the etiologic diagnosis of CNE. We review the benefits and limitations of PCR to diagnose IE and we propose advances that will be necessary to secure a place for PCR in guiding therapy.

Diagnosis of culture-negative endocarditis: The role of the Duke criteria and the impact of transesophageal echocardiography

Background The Duke criteria have been shown to be more sensitive than the von Reyn criteria in the diagnosis of culture-positive endocarditis but to date have not been fully validated for culture-negative endocarditis (CNE). The aim of this study was (1) to compare the diagnostic accuracy of the Duke criteria versus clinical judgment and the von Reyn criteria in CNE and (2) to assess the diagnostic impact of transesophageal echocardiography (TEE) on the Duke criteria in CNE. Methods The study group consisted of 49 patients with suspected CNE in whom the presence (n = 32) or absence (n = 17) of endocarditis was confirmed by surgery, autopsy, or both. All patients underwent transthoracic echocardiography (TTE) and TEE. They were classified into a Duke category initially with TTE data only, and then the Duke categories were reevaluated with the additional TEE data. Results The Duke criteria demonstrated a significantly higher sensitivity (72%) than the von Reyn criteria (28%; P =.0008) and a higher specificity (100%) than clinical judgment (76%; P =.02). No major differences were noted between sensitivities of the Duke criteria and clinical judgement. TEE significantly augmented the capacity to diagnose CNE by Duke criteria versus TTE (P <.05). Conclusions The Duke criteria are of high diagnostic validity for the conduction of clinical studies on CNE. They have the potential to affect clinical decision-making, based on the higher specificity versus clinical judgment. TEE appears to be crucial for the diagnosis of CNE when the Duke criteria are applied. The diagnostic differentiation between CNE, sclerotic valve degeneration, and nonbacterial thrombotic endocarditis remains a challenge. (Am Heart J 2001;142:146-52.)

Epidemiologic and clinical characteristics of Bartonella quintana and Bartonella henselae endocarditis: a study of 48 patients.

Epidemiologic and clinical characteristics of Bartonella quintana and Bartonella henselae endocarditis: a study of 48 patients.

Vegetation biopsy using transesophageal echocardiography guidance: A technique to aid in diagnosis of culture-negative endocarditis

A method of obtaining a vegetation sample in a culture-negative endocarditis is described. A combination of fluoroscopy and transesophageal echocardiography was utilized to obtain the sample. The results positively influenced the diagnosis and treatment in this 16-yr-old male with complex congenital heart disease.

Immunoblotting in the diagnosis of culture negative endocarditis caused by streptococci and enterococci.

To improve the diagnosis of culture negative endocarditis by diagnosing cases due to streptococci and enterococci. Serum samples were immunoblotted against extracts of the commonest streptococci and enterococci. They were selected from patients with a cardiac murmur, persistent pyrexia and at least three negative blood cultures. The presence of patterns of endocarditis species specific antigenic bands was measured and correlated with clinical outcome. Negative serology was found in 28 patients where the diagnosis of endocarditis was rejected or, if proved, staphylococcal, yeast, Gram negative, systemic lupus erythematosus, due to Q fever or Chlamydia psittaci or nonbacterial thrombotic. Positive serology was found in 27 of the 34 patients where the response to antibiotics suggested streptococcal or enterococcal infection. In 22 of these there was objective evidence of endocarditis. Positive serology was also found in three of four further patients with vegetations at necropsy. The identification of patterns of antibody response on immunoblotting can be used to make a specific diagnosis of streptococcal or enterococcal endocarditis in the absence of positive blood cultures.