Neonatal sepsis: evaluation of risk factors and histopathological examination of placentas after delivery

Abstract

Neonatal sepsis is a clinical syndrome defined by systemic signs of infection in newborns accompanied by bacteremia. Can be responsible for serious consequences for the newborn child, characterized at the birth as early sepsis or late onset sepsis, with high rate of neonatal morbidity and mortality. Pathological agents such as Escherichia coli (E. coli), Streptococcus agalactiae (S. agalactiae), Ureaplasma urealyticum and Mycoplasma hominis are most often responsible for intrauterine infections. The objective of this study is to evaluate the factors of neonatal sepsis predisposition in pregnant women through histopathological examination and the apoptotic index of placental tissues and detect DNA of E. coli and S. agalactiae using the Polymerase Chain Reaction (PCR). Histopathological analyses were made and the apoptotic index was determined to verify the levels of possible inflammatory infiltrates and cell death. Placenta samples were collected from November 2013 to May 2014. After DNA extraction, a PCR was performed amplifying the target fragment from the conserved regions of the rpoB (beta-RNA polymerase) polymorphism of E. coli and the factor 1 of S. agalactiae. The apoptosis index was tested with Acridine Orange and the histological procedure with Hematoxylin-Eosin staining. Among 100 samples of placental tissues analyzed by PCR, 48 represented the control group and did not present a risk factor associated with neonatal sepsis, and 52 samples representing the study group had at least one risk factor. Among these 52 samples, 7 (13.4%) had a PCR positive for E. coli. No placenta samples showed a positive PCR for S. agalactiae. The quantification of the apoptotic index did not show statistical significances between the groups and no inflammatory infiltrates were observed. However, histological sections showed fibrinoid necrosis, infarct areas and areas of calcification in all samples. Therefore, the results allow to conclude that the seven patients of experimental group with positive PCR for E. coli had eminent risk factors of neonatal sepsis, and the infection of the urinary tract (UTI) is the main aggravating circumstance. The histopathological examination demonstrated that the risk factors caused significant alterations, producing fibrinoid necrosis and infarcted areas in the placenta, contrary to apoptotic index that didn't differ from the group with unprecedented risk.

Keywords

• escherichia coli
• streptococcus agalactiae
• histopathology
• neonatal sepsis