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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.

Skin and skin structure infection (SSSI) is classified as complicated (cSSSI) if it involves deep subcutaneous tissue or requires surgery. Factors associated with blood culture sampling and bacteremia have not been established in patients with cSSSI. Moreover, the benefit of information acquired from positive blood culture is unknown. The aim of this study was to address these important issues. In this retrospective population-based study from two Nordic cities, a total of 460 patients with cSSSI were included. Blood cultures were drawn from 258 (56.1%) patients and they were positive in 61 (23.6%) of them. Factors found to be associated with more blood culture sampling in multivariate analysis were diabetes, duration of symptoms shorter than 2 days and higher C-reactive protein (CRP) level. Whereas factors associated with less frequent blood culture sampling were peripheral vascular disease and a surgical wound infection. In patients from whom blood cultures were taken, alcohol abuse was the only factor associated with culture positivity, as CRP level was not. Patients with a positive blood culture had antibiotic streamlining more often than non-bacteremic patients. A high rate of blood culture positivity in patients with cSSSI was observed. Factors related to more frequent blood culture sampling were different from those associated with a positive culture.

The impact of the short-incubation matrix-assisted laser desorption ionization time-of-flight (si-MALDI-TOF) mass spectrometry technique was evaluated in the treatment of bloodstream infections (BSIs) caused by Pseudomonas aeruginosa, Enterococcus spp., and Amp-C producing Enterobacteriaceae. A total of 124 bacteremia episodes were divided into 2 groups: i) si-MALDI-TOF group (n = 69) and ii) control group (n = 55). Identification by si-MALDI-TOF resulted in 12.8% increase in cases receiving appropriate antibiotic treatment within 48 h from blood culture draw. The importance of the rapid identification was emphasized in BSIs caused by enterococci (n = 62), where si-MALDI-TOF led to appropriate antibiotic treatment in 87.9% of cases (versus control group 65.5%, P = 0.036). Implementation of si-MALDI-TOF technology for microbial identification was associated with increased proportion of patients receiving effective antibiotic treatment within 48 h from blood culture draw. The effect was most significant in BSIs caused by enterococcal species and in a subgroup of immunosuppressed patients.