Background: Incidence density of sepsis (IDS) is a ratio that measures the frequency with which a sepsis occurs in newborns per 1.000 days of hospital stay in the neonatal unit(NU). IDS is highly dependent of the birth weight(bw). Its measurement is a useful epidemiological tool in analysing the attack rate of sepsis in the NUs corrected by the hospital stay.

Aim/Subjects: To assess the IDS of all neonates admitted at the NU who developed or were suspected of sepsis in the through the years 1992 to 1995. The sepsis were confirmed by blood cultures, and they were stratified into three bw's groups.

Results: There were 2.083 neonates and 103 had true sepsis(4.9%), and 11 developed at least two episodes of sepsis with positive blood culture. Overall there were 118 episodes of sepsis.Table

Table 1
Full size table

Conclusions: The largest IDS was exhibited by the greater weight's group in comparison with the tiniest and intermediate (p<0.05) bw's group. These apparently striking findings, may be explained by the admission policy of the UN. Neonates who weight more than 2,500g, are not routinely admitted, unless they have high risk score of sepsis, show abnormal clinical signs or have congenital anomalies amenable to surgery. Therefore, this bw's group of neonates represent in our UN a group of high risk, subjected to invasive diagnostic and treatment procedures that expose them with greater probability to acquire an infection. Smallest or very low-birth-weight neonates “per se”, constitute a high-risk nosocomial sepsis group.