Staphylococcal infections in children, California, USA, 1985-2009

Abstract

We conducted a retrospective, observational, population-based study to investigate the effect of staphylococcal infections on the hospitalization of children in California during 1985-2009. Hospitalized children with staphylococcal infections were identified through the California Office of Statewide Health Planning and Development discharge database. Infections were categorized as community onset, community onset health care-associated, or hospital onset. Infection incidence was calculated relative to all children and to those hospitalized in acute-care facilities. A total of 140,265 records were analyzed. Overall incidence increased from 49/100,000 population in 1985 to a peak of 83/100,000 in 2006 and dropped to 73/100,000 in 2009. Staphylococcal infections were associated with longer hospital stays and higher risk for death relative to all-cause hospitalizations of children. The number of methicillin-resistant Staphylococcus aureus infections increased, and the number of methicillin-susceptible S. aureus infections remained unchanged. Children <3 years of age, Blacks, and those without private insurance were at higher risk for hospitalization.

Figure 1

Hospitalization trends for children <17 years of age, California, USA, 1985–2009. The incidence of hospitalizations and mean length of stay for children with staphylococcal infection (SI) are compared with the incidences of hospitalizations for cellulitis (Diagnosis Related Group [DRG] 279 or Medicare Severity–DRG 602–603) and for all-cause hospitalizations of children. The horizontal line separates the incidence graphs, which are to be read against the left axis, and the graph for length of stay, which is read against the right axis.

Figure 2

Hospitalization trends for children <17 years of age with staphylococcal infection, California, USA, 1985–2009. Data are no. of patients/100,000 population, except as indicated for children <1 year of age. A) Trends by sex. B) Trends by race. C) Trends by age group, age >1 year. D) Trends for infants (children <364 days of age) compared with trends for children 1–17 years of age; *number/100,000 children <1 year of age.

Figure 3

Hospitalization trends for children <17 years of age with staphylococcal infection (SI), California, USA, 1985–2009. A) Population incidence of particular SI-associated diagnoses relative to the incidence of the same diagnoses in 2000. B) Percentage of all SI-coded hospitalization records that were further classified by various types of SI; the classification code has been available only since 1994. C) Trends for types of SI with cellulitis; available only since 1994. Data are no. of patients/100,000 population. D) Trends for types of SI with pneumonia; available only since 1999. Data are no. of patients/1,000,000 population. E) Trends for types of SI with septicemia; available only since 1998. Data are no. of patients/1,000,000 population. MSSA, methicillin-susceptible Staphylococcus aureus; MRSA, methicillin-resistant S. aureus.

Figure 4

Hospitalization trends for children 1 month to 17 years of age with Staphylococcus aureus infection, by infection onset, California, USA, 1996–2009. Data are no. of patients/100,000 population. A) Incidence of methicillin-susceptible S. aureus. B) Incidence of methicillin-resistant S. aureus.