Platelet count and neonatal sepsis: a high prevalence of Enterobacter spp

Sepsis is a common complication in the neonatal intensive care unit. It is most common in the smallest and most premature infants in whom the clinical presentation can be subtle and nonspecific. The objectives of the present study were to identify the most common organisms causing sepsis and their associations with thrombocytopenia.

This is a retrospective case analysis of blood culture positive patients between March 2003 and July 2007 in a single centre. We enrolled 53 eligible neonates whose blood culture yielded positively for any organism. Blood for the culture was obtained from a peripheral vessel. The data was analysed for differences in platelet and neutrophil count in terms of the microorganisms causing sepsis using chi-square and Fisher's exact tests, analysis of variance and Kruskal-Wallis, as appropriate.

The most common organism in the blood culture was Enterobacter spp. with 21 cases (39.6 percent) and the least common was coagulase-positive Staphylococcus spp. The most common organisms in infants with normal weight and early onset sepsis were coagulase-positive Staphylococcus spp. (50 percent and 36.7 percent, respectively), while in other neonates with low birth weight, very low birth weight and late onset sepsis, the most common organism was Enterobacter spp. (40.9 percent, 71.4 percent and 47.8 percent, respectively). The patients with Enterobacter spp. sepsis had a higher incidence of thrombocytopenia. The mortality rate was 15.1 percent (8/53 cases), which was significantly higher among those with the Enterobacter spp. sepsis (five cases, p-value is 0.033).

Our study shows the changes in the pattern of late onset neonatal infections in the neonatal intensive care unit. Enterobacter spp. is the most common organism causing neonatal sepsis accompanying thrombocytopenia.