The pneumococcal vaccine effect on the epidemiology of community acquired bacteremia (CAB) among children in Israel during the years 2004-2016
D. Geller1, R. Almog2, Y. Geffen3, I. Kassis4.
1Rambam Health care Campus, Pediatric Infectious Diseases Unit, Haifa, Israel.
2Rambam Health care Campus, Epidemiology Unit, Haifa, Israel.
3Rambam Health care Campus, Clinical Microbiology Laboratory, Haifa, Israel.
4Ruth Rappaport Children's Hospital of Haifa- Rambam health care Campus, Pediatric Infectious Diseases Unit, Haifa, Israel.
Background
Pneumococcal vaccine PVC-13 was routinely introduced in mid- 2010 to the routine Israeli immunization program. As a result, epidemiology of CAB among children in Israel is changing. 
Methods
Retrospective study, analyzing data of children aged 0-18 years who were hospitalized in a tertiary medical center serving northern Israel with CAB between the years 2004-2016.  S. pneumoniae proportion among bacteremia cases and the rate per 1000 hospitalized children were compared between pre and post pneumococcal vaccination introduction. 
Results
During the study period, 275 CAB events were identified: with S. pneumoniae (26.9%), S. aureus (12.4%), Brucella (11.6%) and E. coli (10.9%). In the post-vaccination period, there was a significant reduction in pneumococcal bacteremia caused by strains covered by PCV-13. Pneumococcal bacteremia rate per 1000 hospitalized patients decreased significantly from 1.59 to 0.6 (p< 0.001). However, pneumococcus is still a common pathogen mainly due to types not included in the vaccine. Bacteremia caused by other specific bacteria was not significantly changing, except Group A streptococcus, whose incidence increased in the post-vaccination era. The proportion of penicillin resistant pneumococcal isolates decreased dramatically (50.9% to 5.3%), while there were no other significant changes in antibiotic resistance. During the study period, there was a steady decline in the incidence of all bacteremia. In 2015 - 2016 the number of cases increased mainly due to Brucella outbreak (15 cases in 2015-2016 compared to 3 in 2010-2014).
Conclusions
This study demonstrates that the introduction of PVC13 has a double positive effect: a sharp decrease in cases with a significant decrease in pneumococcal resistance to antibiotic treatment, there was overall decline in CAB, but this trend was reversed in the years 2015-2016, due to a Brucella outbreak.

THE PNEUMOCOCCAL VACCINE EFFECT ON THE EPIDEMIOLOGY OF COMMUNITY ACQUIRED BACTEREMIA (CAB) AMONG CHILDREN IN ISRAEL DURING THE YEARS 2004-2016