Clinical features of nosocomial infections by extended-spectrum β-lactamase-producing Enterobacteriaceae in neonatal intensive care units

Aim: To determine the risk factors for the acquisition of nosocomial extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae infection in infants hospitalized in neonatal intensive care units (NICUs) and to evaluate the therapeutic outcome of these infants. Methods: We retrospectively reviewed the medical records of infants with nosocomial ESBL-producing Enterobacteriaceae infection hospitalized in NICUs at Chang Gung Children's Hospital in 2001. The clinical features of these infants were compared with a cohort of non-ESBL-producing Enterobacteriaceae -infected infants during the same period. The therapeutic outcome of the infants in the ESBL group was analysed. Results: Seventy infants were included in this study. Thirty-one infants with 34 isolates were identified in the ESBL group and 39 infants with 42 isolates in the non-ESBL group. Of the parameters analysed, including gestational age, birthweight, length of hospital stay before onset, the number of antibiotics used, the duration of third-generation cephalosporin usage and the number of patients receiving a third-generation cephalosporin prior to the onset of infection, no significant difference was found between the two groups. The infection-contributed case fatality rate was 3.0% (1 of 33) in the ESBL group, not significantly different from that in the non-ESBL group (1 of 41, 2.4%). Of the 31 patients in the ESBL group, 18 were treated with a carbapenem as definitive therapy while 13 were treated with a non-carbapenem antibiotic regimen. No significant difference was noted in terms of mortality rate between the two subgroups. Conclusion: The outcome of the infants hospitalized in the NICU with ESBL-producing enterobacterial infections was not indispensably grave, even when treated with a non-carbapenem antibiotic regimen. The risk factors for the acquisition of ESBL-producing enterobacterial infections in these infants were not identified in this series.