No abstract

Treatment of infective endocarditis (IE) should be initiated promptly. This might hamper the chances to identify the causative organism in blood cultures. Microbiological sampling of infected valve in patients undergoing surgery might identify the causative organism. The impact of pre-operative antimicrobial treatment on the yield of valve samples is not known. This study evaluated the impact of the duration of the pre-operative antibiotic treatment on valve culture and 16S rRNA PCR findings from resected endocardial samples. Patients meeting the modified Duke criteria of definite or possible IE and undergoing valve surgery due to IE during 2011–2016 were included from Southern Finland. Eighty-seven patients were included. In patients with shorter than 2 weeks of pre-operative antimicrobial treatment, PCR was positive in 91% ( n = 42/46) and valve culture in 41% ( n = 19/46) of cases. However, in patients who had 2 weeks or longer therapy before operation, PCR was positive in 53% ( n = 18/34) and all valve cultures were negative. In 14% of patients, PCR had a diagnostic impact. In blood-culture negative cases ( n = 13), PCR could detect the causative organism in ten patients (77%). These included five cases of Bartonella quintana , one Tropheryma whipplei , and one Coxiella burnetii . Long pre-operative antimicrobial treatment was shown to have a negative impact on microbiological tests done on resected endocardial material. After 2 weeks of therapy, all valve cultures were negative, but PCR was positive in half of the cases. PCR aided in diagnostic work-up, especially in blood culture negative cases. Electronic supplementary material The online version of this article (10.1007/s10096-018-03451-5) contains supplementary material, which is available to authorized users.

Background Health care-associated infective endocarditis (HAIE) and intravenous drug use-related IE (IDUIE) have emerged as major groups in infective endocarditis (IE). We studied their role and clinical picture in population-based survey. Methods A population-based retrospective study including all adult patients diagnosed with definite or possible IE in Southern Finland in 2013-2017. IE episodes were classified according to the mode of acquisition into three groups: community-acquired IE (CAIE), HAIE and IDUIE. Results Total of 313 episodes arising from 291 patients were included. Incidence of IE was 6.48/100,000 person-years. CAIE accounted for 38%, HAIE 31% and IDUIE 31% of IE episodes. Patients in IDUIE group were younger, they had more frequently right-sided IE (56.7% vs 5.0%, P<0.001) IE and S. aureus as etiology (74.2% vs 17.6%, P<0.001) compared to CAIE group. In-hospital (15.1% vs 9.3%, P=0.200) and cumulate one-year case-fatality rates (18.5% vs 17.5%, P=0.855) were similar in CAIE and IDUIE. Patients with HAIE had more comorbidities, prosthetic valve involvement (29.9% vs 10.9%, P=0.001), enterococcal etiology (20.6% vs 5.9%, P=0.002) and higher in-hospital (27.8% vs 15.1%, P=0.024) and cumulative one-year case-fatality rate (43.3% vs 18.5%, P<0.001) than patients with CAIE. Staphylococcus aureus caused one-fifth of IE episodes in both groups. Conclusion Our study indicates that in areas where injection drug use is common IDUIE should be regarded as a major risk group for IE along with HAIE and not seen as part of CAIE. Three different risk groups, CAIE, HAIE and IDUIE, with variable characteristics and outcome should be recognized in IE.