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Overview of Neonatal Infections


Brenda L. Tesini

, MD, University of Rochester School of Medicine and Dentistry

Reviewed/Revised Jul 2022

Neonatal infection can be acquired

  • In utero transplacentally or through ruptured membranes

  • In the birth canal during delivery (intrapartum)

  • From external sources after birth (postpartum)

In utero infection

In utero infection, which can occur any time before birth, results from overt or subclinical maternal infection. Consequences depend on the agent and timing of infection in gestation and include spontaneous abortion Congenital Syphilis Congenital syphilis is a multisystem infection caused by Treponema pallidum and transmitted to the fetus via the placenta. Early signs are characteristic skin lesions, lymphadenopathy... read more Congenital Syphilis , intrauterine growth restriction, premature birth Preterm Labor Labor (contractions resulting in cervical change) that begins before 37 weeks gestation is considered preterm. Risk factors include prelabor rupture of membranes, uterine abnormalities, infection... read more , stillbirth Stillbirth Stillbirth is fetal death (fetal demise) at ≥ 20 weeks gestation (> 28 weeks in some definitions). Management is delivery and postpartum care. Maternal and fetal testing is done to determine... read more , congenital malformation (eg, rubella Congenital Rubella Congenital rubella is a viral infection acquired from the mother during pregnancy. Signs are multiple congenital anomalies that can result in fetal death. Diagnosis is by serology and viral... read more ), and symptomatic (eg, CMV Congenital and Perinatal Cytomegalovirus Infection (CMV) Cytomegalovirus infection may be acquired prenatally or perinatally and is the most common congenital viral infection. Signs at birth, if present, are intrauterine growth restriction, prematurity... read more Congenital and Perinatal Cytomegalovirus Infection (CMV) , toxoplasmosis Congenital Toxoplasmosis Congenital toxoplasmosis is caused by transplacental acquisition of Toxoplasma gondii. Manifestations, if present, are prematurity, intrauterine growth restriction, jaundice, hepatosplenomegaly... read more Congenital Toxoplasmosis , syphilis Congenital Syphilis Congenital syphilis is a multisystem infection caused by Treponema pallidum and transmitted to the fetus via the placenta. Early signs are characteristic skin lesions, lymphadenopathy... read more Congenital Syphilis ) or asymptomatic (eg, CMV) neonatal infection.

Intrapartum infection

Neonatal infections with herpes simplex viruses, HIV, hepatitis B, group B streptococci, enteric gram-negative organisms (primarily Escherichia coli), Listeria monocytogenes, gonococci, and chlamydiae usually occur from passage through an infected birth canal. Sometimes ascending infection can occur if delivery is delayed after rupture of membranes.

Postpartum infection

Risk factors for neonatal infection

Maternal IgG antibodies are actively transported across the placenta, but effective levels for all organisms are not achieved until near term. IgM antibodies do not cross the placenta. Premature infants have decreased intrinsic antibody production and reduced complement activity. Premature infants are also more likely to require invasive procedures (eg, endotracheal intubation, prolonged IV access) that predispose to infection.

Symptoms and Signs of Neonatal Infections

Symptoms and signs of infection in neonates tend to be nonspecific (eg, vomiting or poor feeding, increased sleepiness or lethargy, fever or hypothermia, tachypnea, rashes, diarrhea, abdominal distention). Many congenital infections acquired before birth can cause or be accompanied by various symptoms or abnormalities (eg, growth restriction, deafness, microcephaly, anomalies, failure to thrive, hepatosplenomegaly, neurologic abnormalities).

Diagnosis of Neonatal Infections

  • Clinical evaluation

Treatment of Neonatal Infections

  • Antimicrobial therapy

The primary treatment for presumed bacterial infection in the neonate is prompt empiric antimicrobial therapy with drugs such as ampicillin and gentamicin or ampicillin and cefotaxime. Final drug selection is based on culture results similar to the practice in adults, because infecting organisms and their sensitivities are not specific to neonates. However, drug dose and frequency are affected by numerous factors, including age and weight (see tables in Antibiotics in Neonates Antibiotics in Neonates In neonates, the extracellular fluid (ECF) constitutes up to 45% of total body weight, requiring relatively larger doses of certain antibiotics (eg, aminoglycosides) compared with adults. Lower... read more ).

Drugs Mentioned In This Article

Drug Name Select Trade
Garamycin, Genoptic, Genoptic SOP, Gentacidin, Gentafair, Gentak , Gentasol, Ocu-Mycin
NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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