Background: The aim of this study was to estimate frequency, aetiology and results of treatment of nosocomial sepsis (NS) in extremely low birth weight (ELBW) infants (< 1001 g birth weight) treated in the intensive care unit in the years 1999-2002. Material/Methods: 129 subsequently admitted ELBW patients were included into the analysis. Late-onset sepsis was diagnosed upon clinical symptoms and positive blood culture.Results: Sepsis developed in 39.5% of analysed patients, majority of infections were caused by Gram-positive bacteria (58.0%), Gram-negative bacteria accounted for 37.6% cases, in 4.4 % sepsis was caused by fungi. Among Gram-negative bacteria Klebsiella sp. were the most frequent cause of NS, but the highest mortality (60%) was present in sepsis due to Acinetobacter sp.Conclusions: Risk of sepsis was higher in infants with longer duration of mechanical ventilation. Affected infants required longer ventilator treatment and longer stay in the ICU.

Keywords: nosocomial sepsis, extremely low birth weight, neonates, Mortality