Epidemiology of streptococcus pneumoniae-induced hemolytic uremic syndrome in Utah children

Background: Hemolytic uremic syndrome (HUS) is an uncommon complication of invasive pneumococcal disease (IPD) in children. Few studies examine the Streptococcus pneumoniae serotypes associated with HUS. Our objective was to describe the epidemiology of S. pneumoniae-related HUS (SP-HUS) and the serotypes associated with HUS in Utah children. Methods: We reviewed separate longitudinal databases of HUS and IPD. These included all children <18 years cared for at Primary Children's Medical Center, Salt Lake City, UT, with IPD from 1997 to 2008 and all children in Utah with HUS since 1971. Results: We identified 435 Utah children with culture-confirmed IPD (1997-2008) and 460 with HUS (1971-2008). There were no reported cases of SP-HUS before 1997. With the introduction of pneumococcal conjugate vaccine (PCV-7) in 2000, the percentage of IPD complicated by SP-HUS has increased from 0.3% to 5.6% (P < 0.001). Pneumonia (P = 0.051) and empyema (P = 0.012) were associated with the development of SP-HUS compared with IPD without SP-HUS. Children with SP-HUS also required ICU care and had longer stays than those with IPD alone. Only serotype 3 appeared associated with SP-HUS (P = 0.067). Conclusions: We identified an increasing incidence of SP-HUS in Utah children. SP-HUS is a serious complication of IPD associated most frequently with pneumonia and empyema because of serotypes not included in the PCV-7, particularly serotype 3.