Israel Medical Association Journal

Background: The introduction of pneumococcal conjugate vaccine-13 (PCV-13) has reduced the burden of invasive pneumococcal disease.

Objective: To characterize true positive blood cultures of children who presented to our hospital following implementation of the PCV-13 vaccine.

Methods: A retrospective study was conducted on positive blood cultures of children presenting with fever from 2010–2017. Subjects were divided into two age groups: a younger group 3–36 months and an older group 3–18 years. Patients were classified as either having or not having a focus of infection at the time of their bacteremia. Pneumococcal isolates were typed at Israel's Streptococcal Reference Laboratory.

Results: The samples included 94 true positive blood cultures. Focal infection with concomitant bacteremia was more common than bacteremia without a focus both overall: 67/94 (71%) vs. 27/94 (28.7%), P <0.001 as well as in the two groups: 32/48 (66%) vs. 16/48 (33%), P = 0.02 in the younger group and 35/46 (76%) vs. 11/46 (24%), P = 0.001 in the older group. Streptococcus pneumoniae was the most common pathogen overall, 27/94 (29%), and in the younger group, 21/48 (44%), but rare in the older group, 6/46 (13%). In the latter, Brucella species predominated, 12/46 (26%), along with Staphylococcus aureus 12/46 (26%).

Conclusions: Our findings are consistent with other studies reporting decreased pneumococcal bacteremia, bacteremia primarily accompanying focal infection, and changing etiological agents among PCV-13-vaccinated children. Brucella species was prominent in older children with osteoarticular infections. Ongoing surveillance is warranted to better understand the implications of PCV-13.

Background: Once a well-recognized entity, occult bacteremia (OB) is no longer a significant or serious bacterial infection. First following the introduction of the Haemophilus influenzae type B vaccine and now with the implementation of the conjugate pneumococcal vaccine (PCV), the number of cases has declined significantly. This has led to a change in many published guidelines to avoid taking blood cultures in fully vaccinated children presenting with fever. In Israel, the introduction of the PCV13 is now widespread. 

Objectives: To assess the incidence and outcome of OB, specifically by Streptococcus pneumoniae, in a single large pediatric medical center. 

Methods: We conducted a retrospective review of all cases of pneumococcal bacteremias in the years 2008–2013 and specifically those considered occult. 

Results: Of 355 cases of bacteremia diagnosed during the study period, 164 were caused by S. pneumoniae and 20 (12.8%) were considered occult. None of the OB cases had any complications. OB was not found in children over the age of 36 months. There was a change in the serotypes involving pneumococcal OB. 

Conclusions: OB is uncommon in the PCV-vaccinated population and the serotypes involved have changed.