Bloodstream infections (BSI) are a leading cause of morbidity and mortality in hospitalized patients. Moreover, a significant concern is antibiotic resistance among causative agents. Surveillances of BSI provide important information for developing therapeutic guidelines and helping the prevention strategies to evolve.

We report a 15-year surveillance of community and nosocomial bacteremias in hospitals and clinics of three Cantons of Switzerland (VD, NE, JU). Data were collected by infection control nurses. We analyzed retrospectively the data according to 3 distinct periods: 2001–2005, 2006–2010 and 2011–2015.

From 2001–2015, we observed 11,788 BSI, 8858 community (75%) and 2930 nosocomial (25%). Community BSI proportion increased over the observation period (respectively 6.8, 8.39 and 10.11/1000 admissions). Mean duration stay remained stable (6.14–6.71 days). Mean age significantly increased over the years (from 64–69 years, P<0.001). Most common sources of nosocomial BSI were catheter and urinary related. The proportion of urinary related BSI increased over time from 15.1–25.9% (P<0.001). However, the proportion linked to a urinary catheter remained stable (from 44.1–47.4, P=0.69). E. coli is the most common microorganism (36.3% of community and 22.4% of nosocomial BSI). Proportion of Enterococci in nosocomial BSI significantly increased over time (from 6.1–10.4%, P=0.03). Moreover, the proportion of S. aureus with methicillin resistance (MRSA) significantly decreased from 5.7–2.9% (P=0.05) in community BSI and from 11.6–7.9% (P=0.27) in nosocomial BSI. Concomitantly, the proportion of E. coli with extended spectrum beta-lactamase (ESBL) significantly increased among community E. coli BSI, but not in nosocomial BSI (from 1.3–4.5% P<0.001 and 4.8–7.0% P=0.32, respectively).

Proportion of community BSI increased over time contributing to risk factors for developing nosocomial infections. Catheter and urinary related infections should be a priority target in order to prevent nosocomial BSI. Multidrug resistant bacteria distribution changed gradually, resulting in a significant MRSA decrease and an increase in ESBL E. coli in the community. This tendency, also not significant, is also true in nosocomial BSI and should be taken into account when treating the patient. Concomitantly, a special attention should be made to Enterococci seen the recent vancomycin-resistant Enterococci outbreaks in this part of Switzerland.