Neonatal Sepsis: All You Need to Know

The term sepsis refers to an infection throughout the body. In this case, we are taking about infection spread throughout the newborn infant, due to the newborn becoming infected soon after or during birth.  Neonatal sepsis is particularly dangerous as it can lead to serious medical complications as well as death. Signs of neonatal infection are not very specific, which means that doctors caring for the infant must have a very high level of suspicion for sepsis so that treatment can begin immediately in the form of what doctors call broad spectrum antibiotics (medications that work against a wide range of bacterial strains that may be causing the infection).

Common microorganisms that cause neonatal sepsis include Group B Streptococcus (GBS) in particular, which has been discussed on The Pulse, but also include E. coli, Klebsiella, Listeria, and Staphylococcus aureus.  Also known as Streptococcus agalactiae, GBS is a group of bacteria that can infect anybody, but is a particular problem in pregnancy as it can enter through the cervix as what obstetricians call an ascending infection, an infection that moves upward through the birth canal. When it ascends, GBS can cause disease, such endometritis (inflammation of the lining of the uterus), chorioamnionitis (inflammation of the fetal membranes and amniotic fluid), and urinary tract infections (UTI), although various other types of bacteria also can cause these three conditions. Most of the time GBS does not hurt adult women, but it can transfer to the baby during labor and cause neonatal sepsis. Situations that can cause GBS to ascend through the birth canal, increasing the risk to the baby, include repeated digital examinations by the doctor (fingers inserted into the vagina or rectum), your water breaking early (premature rupture of membranes, preterm premature rupture of membranes, and prolonged rupture of membranes), and a long period of time (more than 18 hours) between rupture of the membranes and delivery.

Neonatal sepsis is particularly dangerous as it can lead to serious medical complications as well as death.

As a pregnant woman you can and should be tested for GBS. A few weeks before delivery, generally at 36-37 weeks gestation, your obstetrician will swab samples from your vagina and rectum. Samples will be cultured in a laboratory to see if GBS is present. If your screening test does show that you carry GBS, you will be given broad spectrum antibiotic medication intravenously (IV) to prevent neonatal GBS infection during labor. The laboratory also will analyze your samples further to determine which antibiotics your particular GBS strains are most susceptible to and, if appropriate, your antibiotic regimen will be switched. Generally, the antibiotic of choice is penicillin, unless you have a penicillin allergy. If you have penicillin allergy, but you are not at high risk of suffering an anaphylactic reaction (a severe allergic reaction), your doctor may give you cefazolin. Otherwise, the next two options are clindamycin and erythromycin, if your GBS tests show that your GBS is susceptible to either of these antibiotics. In the event that you carry GBS that is resistant both to clindamycin and erythromycin, in many cases the next choice will be vancomycin.

In addition to the mother carrying GBS in her vagina, factors increasing the risk that a neonate will develop sepsis include previous GBS neonatal sepsis (the mother gave birth to another infant who developed sepsis), maternal sepsis (the mother herself is septic during pregnancy), chorioamnionitis (infection of the fetal membranes, placenta, and amniotic fluid), fever in the mother (temperature above 38 degrees Celsius), prematurity of less than 37 weeks gestation, and early premature rupture of membranes.

Newborn infants who are septic typically develop fever, poor feeding, breathing difficulty, hypoxia (low oxygen levels) vomiting, fast or slow heart beat, reduced activity and muscle tone, hypoglycemia (low blood sugar), jaundice (yellowing of the skin and sclera of the eyes) within 24 hours of birth, and seizures.

Newborn babies with one risk factor for sepsis must be monitored for 12 hours after birth. Those with multiple risk factors must be started on antibiotics, and samples of blood need to be taken before the antibiotic therapy starts so that the blood can be tested for specific types of bacteria. If infection of the layers around the brain (meningitis) is suspected, then doctors will also need to perform what’s called a lumbar puncture to obtain fluid from the central nervous system to check it for signs of infection.

David Warmflash
Dr. David Warmflash is a science communicator and physician with a research background in astrobiology and space medicine. He has completed research fellowships at NASA Johnson Space Center, the University of Pennsylvania, and Brandeis University. Since 2002, he has been collaborating with The Planetary Society on experiments helping us to understand the effects of deep space radiation on life forms, and since 2011 has worked nearly full time in medical writing and science journalism. His focus area includes the emergence of new biotechnologies and their impact on biomedicine, public health, and society.

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