Late neonatal sepsis (i.e. sepsis, the clinical manifestation of which occurs between 4 and 7 days of life or later) is a major cause of death in very low birth weight infants. Typically, a fatal outcome occurs within 3 days of the onset of symptoms of sepsis.

The objective of the study in Israel was to study the dependence of the risk of early death after the development of symptoms of sepsis in very low birth weight infants (less than 1500 g), taking into account perinatal and neonatal risk factors for the pathogen.

For the period 1995-2001 Information on 10,215 very low birthweight children was collected and entered into the national database. The study population included 2,644 children, each of whom had at least one episode of late neonatal sepsis. A total of 3462 cases of late sepsis were analyzed. Logistic regression models were used to determine the risk of early mortality.

It turned out that the early mortality rate (within 3 days of the onset of the disease) was 5.2% (in 179 cases of late sepsis). The most common causative agent for sepsis in this population has been shown to be coagulase-negative staphylococcus - 1736 cases (50.1%), however, early mortality from sepsis caused by this pathogen was only 1.8%. Early mortality from sepsis caused by the six most common Gram-negative bacilli (926 cases) was significantly higher. The highest early mortality rate was observed in sepsis caused by Pseudomonas spp. (22.6%), Klebsiella spp. (10.0%) and Serratia spp. (9.5%). Based on neonatal risk factors, it has been found that sepsis caused by Pseudomonas spp. Increases the risk of premature death by 12.3 times, Klebsiella spp. - 6.3 times, Serratia spp. - 6.2 times, Escherichia spp. - 4.3 times, Enterobacter spp. - 4.1 times and Candida spp. - 3.2 times compared to a septicemia caused by a coagulase negative staphylococcus. In 41.9% of all early deaths, sepsis was caused by Klebsiella spp. and Pseudomonas spp.

In addition, shorter gestational age, shorter chronological age, low weight for an appropriate gestational age, and grade 3-4 intraventricular hemorrhage were separate independent risk factors for early mortality.

Thus, according to the results of this study, it can be noted that the empirical antibiotic therapy for late sepsis in very low bodyweight infants should be active against pathogens such as Pseudomonas spp. , Klebsiella spp. and Serratia spp.