Risk of neonatal septicemia associated with neonatal-maternal-bacterial determinants

Introduction

The triad interaction of neonatal-maternal-bacterial determinants plays a crucial role in the increased incidence of bacterial sepsis during the neonatal period. This study was undertaken to determine whether neonatal-maternal predisposing factors and bacterial pathogens affect the risk of early or late onset sepsis.

Methods

Three hundred neonates in the NICU of two hospitals in Tehran were studied. Blood cultures from neonates with suspected sepsis were performed on BHI broth followed by identification of isolates and testing for their susceptibility to antimicrobial agents. Collectively, neonatal and maternal risk factors such as birth weight, gestation age, PROM, Apgar score, and others were studied in the cultures of proven cases of neonatal sepsis. In univariate binary logistic regression models, the impact of neonatal and maternal factors on sepsis risk was estimated in terms of odds ratio (OR) with 95% confidence interval (CI).

Results

The present study revealed the impact of bacterial pathogens and neonatal and maternal predisposing factors on sepsis as follows. Bacterial pathogens: 14/300 (4.7%) of neonates developed septicemia. Among infected neonates, 64.3% and 35.7% were considered with early-onset and late-onset sepsis, respectively. The most isolated Gram-negative organism was Stenotrophomonas maltophilia (42.8%) followed by Klebsiella pneumonia (28.6%), Escherichia coli (21.4%) and Serratia liquefaciens (7.2%). Neonatal factors: the mean age of neonates ± SD with early-onset sepsis (1.56 ± 0.88) was lower than that of those with late-onset sepsis (10.40 ± 5.50) and this difference was statistically significant (P < 0.05). Low birth weight (LBW) <2,500 g increased the risk of sepsis to more than twofold (OR = 2.9, 95% CI = 1.17 to 9.86; P < 0.01). Gestation age (GA) <29 weeks was significantly associated with sepsis (P < 0.01). The septicemia, in turn, increased the risk of death up to more than fivefold (OR = 5.5; 95% CI = 1.98 to 15.3; P < 0.01). More than one-half of septic neonates had positive result for CRP whereas only 1.9% of neonates with sepsis were CRP-negative, and this difference was statistically significant (P < 0.001). Maternal factors: PROM affected the sepsis risk to more than threefold (OR = 3.8; 95% CI = 1.37 to 10.56; P < 0.05).

Conclusions

The present study reveals that specific neonatal and maternal factors are associated with increased risk of sepsis. Among the studied factors, prematurity of neonates explained as GA and LBW are the most important contributors to morbidity in neonate who suffered from sepsis. Furthermore, PROM as a maternal risk factor predisposes a child to neonatal sepsis.