Tehran University Medical Journal

Background: Bacterial sepsis is a main cause of mortality and morbidity especially in preterm newborns. The aim of this study was to search the bacterial etiologies of neonatal sepsis in NICU admitted preterm neonates.

Methods: A descriptive cross-sectional study had done in NICU of Ali Asghar Hospital, Tehran, Iran from March 2007 to March 2009. Seventy septicemic preterm newborns (<37 weeks) were studied. At admission day, for blood culture, 1-2 ml of venous blood was drawn after swabbing the venipuncture site with alcohol. After centrifugation of blood samples, deposits were cultured on sheep blood agar and incubated in a candle jar at 37 °C for 48 h and followed by subcultured. Isolates were identified using standard techniques (Nima pouyesh, Iran). Type of isolated bacterial organisms determined. Its correlation with gestational age, birth weight, premature rupture of membranes (PROM) and other variables determined we used the nonparametric two independent sample test, Mann-Whitney U test. Chi-square values (CI 95%, P< 0.05) were calculated for all categorical variables. P-value less than 0.05 considered statistically significant.

Results: Of 70 studied septicemic preterm cases, 17 (10.6%) cases had positive blood culture. Overall gram-negative organisms were more frequent than gram-positive organisms, Klebsiella (K.) pneumoniae, Escherichia (E.) coli and Staphylococcus (S.) aureus organisms were the 3 common causes of bacterial sepsis in studied cases. Early onset sepsis produced by K. pneumonia (40%), E. coli (20%) and S. aureus (20%). K. pneumonia, E. coli, S. aureus had equal incidence in late onset sepsis (26.8%). K. pneumonia was more frequent in early onset sepsis (P= 0.05), and in low birth weight (< 1500 g) neonates (P= 0.005, and PROM (P= 0.05).