Mode of delivery and other risk factors for Escherichia coli infections in very low birth weight infants

BACKGROUND: Infections in newborns remain one of the most significant problems in modern medicine. Escherichia coli is an important cause of neonatal bloodstream and respiratory tract infections and is associated with high mortality. The aim of our study was to investigate the epidemiology of E. coli infection in Polish neonatal intensive care units (NICUs) and resistance to antibiotics, with particular reference to the safety of very low birth weight infants. METHODS: Continuous prospective infection surveillance was conducted in 2009–2012 in five NICUs, including 1,768 newborns whose birth weight was <1.5 kg. Escherichia coli isolates from different diagnostic specimens including blood, tracheal/bronchial secretions and others were collected. All isolates were tested using disk diffusion antimicrobial susceptibility methods. Pulsed-field gel electrophoresis was used to determine the possible horizontal transfer of E. coli among patients. RESULTS: The incidence of E. coli infections was 5.4% and 2.0/1,000 patient-days. The occurrence of E. coli infections depended significantly on the NICU and varied between 3.9% and 17.9%. Multivariate analysis that took into account the combined effect of demographic data (gender, gestational age and birth weight) and place of birth showed that only the place of hospitalisation had a significant effect on the E. coli infection risk. The highest levels of resistance among all E. coli isolates were observed against ampicillin (88.8%) and amoxicillin/clavulanic acid (62.2%). Among E. coli isolates, 17.7% were classified as multidrug resistant. Escherichia coli isolates showed different pulsotypes and dominant epidemic clones were not detected. CONCLUSIONS: Our data indicate that antibiotic prophylaxis in the presence of symptoms such as chorioamnionitis and premature rupture of membranes did not help reduce the risk of E. coli infection. Multivariate analysis demonstrated only one significant risk factor for E. coli infection among infants with a birth weight <1.5 kg, that is, the impact of the NICU, it means that both neonatal care and care during pregnancy and labour were found to be significant.