Healthcare-Associated Infections in Pediatrics

Background and aims. Healthcare-associated infections (HAIs) are known to increase the risk for patient morbidity and mortality in different healthcare settings and thereby to cause additional costs. HAIs typically affect patients with severe underlying conditions, such as patients treated in intensive care units, or patients who have undergone medical procedures, e.g., surgery. HAIs are prevalent also among pediatric patients, but the distribution of the types of infection and the causative agents differ from those detected in adults. The aim of this study was to obtain information on pediatric HAIs in Finland through an assessment of the surveillance of bloodstream infections (BSIs), through two outbreak investigations in a neonatal intensive care unit (NICU), and through a study of postoperative HAIs after open-heart surgery. Methods. The Hospital for Children and Adolescents of the Helsinki University Central Hospital has participated in the BSI surveillance of the Finnish Hospital Infection Program since 1999. These data were utilized in all studies. The epidemiological features of pediatric BSIs were assessed. For the outbreak investigations, case definitions were set and data collected from microbiological and clinical records. The antimicrobial susceptibilities of the Serratia marcescens and the Candida parapsilosis isolates were determined. The S. marcescens isolates were genotyped with pulsed-field gel electrophoresis and the C. parapsilosis blood culture isolates (obtained between the years 1990 and 2002) with Southern blot hybridization by use of a DNA fingerprinting probe. Patient charts were reviewed for the case-control and cohort studies during the outbreak investigations, as well as for those patients who acquired surgical site infections (SSIs) after having undergone open-heart surgery. Also a prospective postdischarge study was conducted to detect postoperative HAIs after open-heart surgery. Results. During 1999-2006, the overall annual BSI rate was 1.6/1,000 patient-days (range by year, 1.2–2.1). High rates (average, 4.9 and 3.2 BSIs/1,000 patient-days) were detected in hematology and neonatology units. Coagulase-negative staphylococci were the most common pathogens both hospital-wide and in each patient group. The overall mortality was 5%. The genotyping of the 15 S. marcescens isolates revealed three independent clusters. All of the 26 C. parapsilosis isolates studied proved to be indistinguishable. No common source was identified for either of the outbreaks, but the NICU was overcrowded during the S. marcescens clusters. In both investigations, low birth weight and prematurity were identified as risk factors. A negative correlation between C. parapsilosis BSIs and fluconazole use in the NICU was detected, and the isolates derived from a single initially susceptible strain became less susceptible to fluconazole over time. Eighty postoperative HAIs, including all severe infections, were detected during hospitalization after open-heart surgery; 34% of those HAIs were SSIs and 25% were BSIs. The postdischarge study found 65 infections likely to be associated with hospitalization. The majority (89%) of them were viral respiratory or gastrointestinal infections, and these often led to rehospitalizations. Of the SSIs, 20% were detected after discharge. Conclusions. The annual hospital-wide BSI rates were stable, and the significant variation detected in some units could not be seen in overall rates. Further studies with data adequately adjusted for risk factors are needed to assess BSI rates in the patient groups with the highest rates (hematology, neonatology). The outbreak investigations showed that horizontal transmission was common in the NICU. Overcrowding and lapses in hand hygiene probably contributed to the spreading of the pathogens. Following long-term use of fluconazole in the NICU, resistance to fluconazole developed in C. parapsilosis. Almost one-fourth of the patients who underwent open-heart surgery acquired at least one HAI. All severe HAIs were detected during hospitalization. The postdischarge study found numerous viral infections, which often led to rehospitalization. Only superficial SSIs, which did not affect the patient outcome, were detected after discharge, suggesting that routine postdischarge surveillance may not be necessary in this patient group.