Serotype prevalence of occult pneumococcal bacteremia.

OBJECTIVE: The licensure and use of a pneumococcal conjugate vaccine that is immunogenic in children who are younger than 2 years may affect the epidemiology of occult bacteremia. This study was conducted to determine the serotype prevalence of Streptococcus pneumoniae isolates from children with occult bacteremia and to document the proportion that would be covered by the recently licensed heptavalent pneumococcal conjugate vaccine. METHODS: A cohort of 5901 children who were 2 to 24 months of age and had a temperature of >/=39.0 degrees C evaluated with a blood culture at an urban tertiary care children's hospital emergency department was studied to determine the prevalence of S pneumoniae serotypes. Patients were excluded if their immune system was suppressed, they had a diagnosis of a focal infection, they were evaluated by lumbar puncture, they were admitted to the hospital, or they died during initial evaluation. Blood cultures were inoculated into pediatric blood culture bottles and processed using an automated carbon dioxide monitoring system. All pneumococcal isolates were serotyped on the basis of capsular swelling with type-specific antisera (Quellung reaction). RESULTS: The study population consisted of 5901 patients. The overall rate of occult bacteremia was 1.9% (95% confidence interval [CI]: 1.5-2.3). S pneumoniae accounted for 92 of 111 isolates (82.9%; 95% CI: 74.6-89.4) in children with occult bacteremia. Eight pneumococcal serotypes were represented: 6A (2%), 9V (6%), 19F (6%), 18C (8%), 4 (9%), 6B (13%), 23F (15%), and 14 (42%). Serotypes 14, 6B, and 23F accounted for 69.3% (95% CI: 58.6-78.7) of typed isolates. In the cohort, 97.7% (95% CI: 92-99.7) of isolated serotypes are represented in the newly licensed heptavalent pneumococcal conjugate vaccine. The single isolated serotype that would not have been covered by the currently licensed heptavalent pneumococcal conjugate vaccine was 6A. CONCLUSIONS: S pneumoniae accounts for the vast majority of bacterial pathogens in children with occult bacteremia. As indicated by the results of this study, the heptavalent pneumococcal conjugate vaccine may prevent the majority of occult pneumococcal bacteremia episodes. The 2 cases of bacteremia with a serotype that would not have been included in the vaccine both were due to serotype 6A. It has been noted that there is potential nonvaccine serotype and subgroup cross-protection (6A from 6B) afforded to children who are immunized with the heptavalent vaccine. The high potential efficacy of the heptavalent pneumococcal conjugate vaccine for strains that cause occult bacteremia in our population may have a profound effect on the treatment of children with fever without a source. There has been an alarming and rapid emergence of antibiotic-resistant pneumococcal strains. Less pressure to use broad-spectrum antibiotics, which in turn causes further antibiotic resistance, should result. Laboratory testing and hospitalization also should be reduced. The prevalence rates determined by this study may be used as baseline data for comparison of serotype rates of occult pneumococcal bacteremia after widespread use of the heptavalent vaccine.

Effects of Medicaid managed care on health care use: infant emergency department and ambulatory services.

OBJECTIVE: Many urban children rely on emergency departments (ED) for ambulatory care. The objective of this study was to determine whether enrollment in Medicaid managed care (MMC) alters ED or other ambulatory care compared with fee-for-service Medicaid (FFSM). METHODS: A prospective cohort study of infants born between May 1994 and April 1995 with a 6-month follow-up period was conducted in an urban, teaching hospital and surrounding ambulatory settings. A consecutive sample of 644 infants enrolled in MMC or FFSM was studied; 92% of eligible patients were enrolled, and 94% completed follow-up. The main outcome measures were 1) proportion of patients in each group visiting an ED, primary care practitioner (PCP), or specialist; 2) mean number of visits per group; and 3) ED reliance (EDR) defined as the proportion of all ambulatory visits occurring in an ED. RESULTS: Fifty-six percent of MMC and 54% of FFSM patients visited an ED (relative risk: 1.03; 95% confidence interval [CI]: 0.83, 1.27). More MMC patients had a sick visit to their PCP (relative risk: 1.34; 95% CI: 1.03, 1.74); no difference in proportion with well-child or specialty visits was found. Although the mean number of total ambulatory, ED, and specialty visits was the same, MMC patients had fewer well-child and more sick visits to the PCP than FFSM patients (P =.01). EDR was 21% for both groups (P =.95). After adjustment for other factors in multivariate analysis, insurance status remained unassociated with EDR (adjusted odds ratio [OR]: 0.91; 95% CI: 0.56, 1.69). Factors associated with EDR included United States-born mother (OR: 5.34; 95% CI: 1.61, 17.68) and use of a hospital-based primary care physician (OR: 2.00; 95% CI: 1.34, 2.98). Variables that characterized infants who were less likely to be ED reliant included adequate maternal prenatal care (OR: 0.52; 95% CI: 0.34, 0.78) and having a mother who completed high school (OR: 0.67; 95% CI: 0.45, 0.99). CONCLUSIONS: Enrollment in MMC did not alter ED usage patterns when compared with FFSM. Some variation in use of other ambulatory services was detected.

Effects of medicaid managed care on quality: childhood immunizations.

BACKGROUND: Underimmunization is distributed unevenly across populations, concentrated among the impoverished. Managed care has stimulated the development of quality indicators such as immunization rates to assess health status of populations. OBJECTIVE: To determine if enrollment in Medicaid managed care (MMC) improves quality of health care as reflected by immunization rates when compared with fee-for-service Medicaid (FFSM). DESIGN. Prospective cohort study of infants born between May 1994 and April 1995 with a 24-month follow-up period. SETTING: Urban teaching hospital and surrounding ambulatory settings. PARTICIPANTS: Consecutive sample of infants (n = 644) enrolled in MMC or FFSM. Ninety-two percent of eligible patients were enrolled, and 87% completed follow-up. MAIN OUTCOME MEASURE: Up-to-date immunization status. RESULTS: Seventy-three percent of the MMC and 72.4% of the FFSM patients were up-to-date on their immunizations: relative risk 1.01, (95% confidence interval [CI] 0.87, 1.17). No differences were found in age at immunization between the MMC and FFSM groups. After adjusting for other factors in multivariate analysis, insurance status remained unassociated with immunization status: adjusted odds ratio (OR) 1.04, (95% CI: 0.90, 1.10). Factors associated with up-to-date immunization included firstborn child, OR 2.28 (95% CI: 1.45, 3.60) and adequate maternal prenatal care, OR 2.24 (95% CI: 1.44, 3.48). Variables characterizing children less likely to be adequately immunized included father living in home with child, OR 0.53 (95% CI: 0.33, 0.85) and using private office-based primary care, OR 0.39 (95% CI: 0.23, 0.63). CONCLUSIONS: Enrollment in MMC did not improve rates of immunizations when compared with FFSM.

Occult bacteremia from a pediatric emergency department: current prevalence, time to detection, and outcome.

OBJECTIVE: To evaluate selected characteristics of occult bacteremia in the post-Haemophilus influenzae type b (HIB) vaccine era. METHODS: A retrospective cohort study was performed involving 5901 children 2 to 24 months old with fever >/=39.0 degrees C evaluated with a blood culture at an urban tertiary care children's hospital emergency department (ED) between February 1993 and June 1996. Patients were excluded if immune-suppressed, diagnosed with a focal infection, evaluated by lumbar puncture, or admitted to the hospital during initial evaluation. Prevalence of occult bacteremia, distribution of current pathogenic organisms, and time to positive culture in a continuously monitored system were determined. All patients with cultures positive for pathogenic bacteria were reevaluated and serious adverse outcomes were documented. RESULTS: The prevalence of occult bacteremia was 1.9% (95% confidence interval: 1.5%-2.3%). Streptococcus pneumoniae accounted for 82.9% of all pathogens and H influenzae was not a causative organism in this cohort. The mean time to positive culture was significantly shorter for pathogens compared with contaminants (14.9 hours vs 31.1 hours). A culture that was positive in