Detection of the causative pathogen in infective endocarditis by means of the LightCycler SeptiFAST® test
Abstract number: P1830
Janata O., Herbich K., Haas Y., Elliott P., Schuster R., Apfalter P.
Objective: Detection of the causative microorganism in infective endocarditis (IE) in pre-treated patients is still a challenge. At least 35% of cases of culture-negative IE can be attributed to prior antimicrobial therapy.
Reported here is a patient with culture negative IE, in whom the causative agent could be diagnosed by means of the new LightCycler SeptiFAST® test, a real-time based multiplex PCR assay allowing for DNA-detection of 25 pathogens within 6 hours from EDTA-treated blood specimens (Roche, Mannheim, Germany).
Case report: A 58-year-old male patient with malaise and anaemia was admitted to hospital. He reported a history of coronary heart disease and diabetes mellitus type II. Four weeks prior to hospitalisation a transurethral prostatic resection had been performed. Laboratory results showed signs of mild, chronic inflammation. Without definitive diagnosis over a period of 17 days he received amoxicillin/clavulanic acid due to elevated C-reactive-protein levels. Under this therapy he developed fever of 38.6°C on day 3 after admission. Transthoracic echocardiography showed no pathology at that time and antibiotics were not changed. After 17 days the patient had to be transferred to the ICU because of cerebral deterioration and respiratory insufficiency. The immediate follow-up revealed an aortic valve endocarditis as well as an embolic stroke by means of transoesophageal echocardiography and computed tomography, respectively. Multiple blood cultures remained negative, supposedly because of prior antibiotic therapy. The new LightCycler SeptiFAST® test was applied and revealed Enterococcus faecalis (Gram-positive panel, chanel 705, melting temperature 62.6°C). The treatment was changed to amoxicillin and daptomycin and the aortic valve was replaced. No enterococci could be cultured from valve-tissue, but amplification of part of the 16S rDNA gene (560bp of the V3-region; Escherichia coli position 8575; amplification primers 27F and 556R) followed by cycle sequencing (ABI PRISM Genetic Analyzer 3130; primer 27F) confirmed the presence of E. faecalis-DNA.
Conclusion: To our knowledge this is the first report of microbiological diagnosis in IE by means of the LightCycler SeptiFAST® test. Further use of this new molecular-biological tool is warranted to confirm its application in pre-treated IE. The method, however, will not replace conventional blood cultures because no antimicrobial susceptibility data are provided.
|Session name:||18th European Congress of Clinical Microbiology and Infectious Diseases|
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