bacterial etiology and antibiotic sensitivity patterns of early-late onset neonatal sepsis among newborns in shiraz, iran 2004-2007

background: neonatal sepsis is a major cause of mortality and morbidity, especially in developing countries. the goal of the present study was to determine the bacterial etiology and antibiotic sensitivity patterns of neonatal sepsis.   methods: this cross sectional study was conducted on 208 neonates admitted with clinically suspected sepsis over a period of 30 months. sepsis was divided into early onset sepsis (eos, ≤5 days of age) and late onset sepsis (los, >5 days of age). the two groups were further divided into proven (culture positive ± abnormal markers) and probable (culture negative + abnormal markers) subgroups. blood culture was performed using bactec.   results: of 208 cases, 90 had neonatal sepsis consisting of 38 (26 proven) presented as eos and 52 (42 proven) as los. in the eos, escherichia coli (e. coli) was the most common organism followed by klebsiella spp, staphylococcus aureus ( s. aureus ). as for los, coagulase-negative staphylococci (cons) were the most common organism followed by enterococcus spp, s. aureus . the antibiogram on the isolated e. coli and klebsiella spp revealed a greater combined sensitivity to cefotaxime. coagulase-negative staphylococci and s. aureus had 100% and enterococcus spp 90% sensitivity to vancomycin.   conclusion: escherichia coli and cons were the most common organisms causing eos and los, respectively. since the antibiotic sensitivity patterns of these organisms are changed, it seems necessary to conduct bacterial etiology studies and to determine antibiotic sensitivity patterns periodically in order to promote the empirical therapy.