Neonatal sepsis is a type of neonatal infection and specifically refers to the presence in a newborn baby of a bacterial blood stream infection (BSI) (such as meningitis, pneumonia, pyelonephritis, or gastroenteritis) in the setting of fever. Older textbooks may refer to neonatal sepsis as "sepsis neonatorum". Criteria with regards to hemodynamic compromise or respiratory failure are not useful clinically because these symptoms often do not arise in neonates until death is imminent and unpreventable. Neonatal sepsis is divided into two categories: early-onset sepsis (EOS) and late-onset sepsis (LOS). EOS refers to sepsis presenting in the first 7 days of life (although some refer to EOS as within the first 72 hours of life), with LOS referring to presentation of sepsis after 7 days (or 72 hours, depending on the system used). Neonatal sepsis is the single most common cause of neonatal death in hospital as well as community in developing country. It is difficult to clinically exclude sepsis in newborns less than 90 days old that have fever (defined as a temperature > 38 °C (100.4 °F). Except in the case of obvious acute viral bronchiolitis, the current practice in newborns less than 30 days old is to perform a complete workup including complete blood count with differential, blood culture, urinalysis, urine culture, and cerebrospinal fluid (CSF) studies and CSF culture, admit the newborn to the hospital, and treat empirically for serious bacterial infection for at least 48 hours until cultures are demonstrated to show no growth.
The mother is not the only one who can contract the bacteria that contributes to sepsis. The child can contribute to the onset of sepsis through multiple factors. Mothers contribute to the risk through a variety of ways like diets during pregnancy and potential intake of foods that are contaminated, through invasive procedures like amniocentesis and cervical cerclage, or contamination of bacteria in the vaginal canal. Infants can contribute to early-onset sepsis through prematurity, congenital anomalies, complicated birth or instrument assisted birth, and low APGAR scores. Testing for neonatal sepsis is done because of how little it physically presents itself in babies. Infants showing no signs of neonatal sepsis will have a sepsis workup done only if concerning factors are shown. Only a small percentage of infants will have a sepsis workup done. Of this small population only 3% to 8% will show positive cultures. Research
Trials of probiotics for prevention of neonatal sepsis have generally been too small and statistically underpowered to detect any benefit, but a randomized controlled trial that enrolled 4,556 neonates in India reported that probiotics significantly reduced the risk of developing sepsis. The probiotic used in the trial was Lactobacillus plantarum. A very large meta-analysis investigated the effect of probiotics on preventing late-onset sepsis (LOS) in neonates. Probiotics were found to reduce the risk of LOS, but only in babies who were fed human milk exclusively.