12.3 Early-Onset & Late-Onset Neonatal Sepsis, GBS & TORCH Infections
Key Takeaways
- Temperature instability, respiratory change, poor feeding, lethargy, apnea, perfusion change, or glucose instability can be neonatal sepsis; deterioration matters more than fever alone.
- Obtain an adequate-volume blood culture before antibiotics when feasible, but do not delay empiric treatment of a symptomatic or unstable infant.
- CBC indices, I:T ratio, CRP, and procalcitonin cannot diagnose or exclude sepsis alone; interpret trends with culture and clinical condition.
- Well-appearing infants with perinatal risk are managed using a validated categorical pathway, multivariate EOS calculator, or structured serial examinations—not one universal observation rule.
- Congenital CMV, toxoplasmosis, rubella, syphilis, and HSV overlap clinically; obtain pathogen-specific testing and treatment promptly.
12.3 Neonatal Sepsis & Congenital Infections
Core Focus: Neonates often deteriorate without fever or a dramatic laboratory abnormality. Recognize subtle change, obtain reliable cultures, start time-sensitive therapy in symptomatic infants, and use a validated risk pathway for well infants.
Early- and late-onset sepsis
Early-onset disease usually reflects vertical exposure; Group B Streptococcus and E. coli are major pathogens. Risks include suspected intraamniotic infection, prolonged rupture, prematurity, and inadequate indicated intrapartum prophylaxis. Late-onset disease reflects community or healthcare exposure and includes staphylococci and resistant gram-negative organisms depending on setting.
Warning signs include temperature instability, apnea, grunting/tachypnea, increasing oxygen need, poor feeding, vomiting/distention, lethargy or irritability, hypotonia, glucose instability, jaundice, pallor/mottling, delayed capillary refill, tachycardia or bradycardia, seizure, or bulging fontanelle. No single sign is required.
Evaluation and treatment
For a symptomatic infant, stabilize airway/breathing/circulation and glucose, obtain an adequate blood culture (commonly at least 1 mL) and indicated labs, and give empiric IV antibiotics promptly. Lumbar puncture is performed when meningitis is suspected or culture/clinical course indicates, when the infant is stable enough. Chest, urine, placental, or other studies depend on age and source.
Ampicillin plus an aminoglycoside is common initial early-onset coverage; late-onset choices follow local flora, resistance, devices, and meningitis risk. Verify neonatal dose and interval by gestational/postnatal age, weight, renal function, and drug levels. Narrow or stop antibiotics based on culture, clinical course, and stewardship protocol.
A CBC is neither sensitive nor specific. Leukopenia, neutropenia, thrombocytopenia, or a high immature-to-total neutrophil ratio can support concern, but the I:T ratio is not a stand-alone diagnostic threshold. CRP rises late; serial low values can support stopping therapy in a well infant but do not justify withholding initial treatment from an ill infant.
Well-appearing infant with EOS risk
Facilities use one of three AAP-supported approaches for infants at least 35 weeks: categorical risk assessment, a multivariate early-onset sepsis calculator, or structured serial physical examinations. Maternal fever/intraamniotic infection, gestational age, duration of membrane rupture, GBS status, antibiotic agent and timing, and the infant's evolving examination all matter. “Less than four hours of penicillin” is not by itself a mandate for NICU admission, laboratory testing, antibiotics, or one universal 36–48-hour stay. Follow the selected institutional pathway and reassess promptly if symptoms develop.
Major congenital infections
| Infection | High-yield clues | Evaluation/treatment principles |
|---|---|---|
| CMV | Growth restriction, petechiae, hepatosplenomegaly, microcephaly, periventricular calcifications, hearing loss | Confirm with saliva/urine PCR in the congenital window; assess hearing, eyes, CNS, blood/liver; antiviral therapy for qualifying symptomatic disease |
| Toxoplasmosis | Chorioretinitis, hydrocephalus, diffuse intracranial calcifications | Maternal/infant serology and PCR; prolonged specialist-directed antiparasitic therapy |
| Rubella | Cataracts, hearing loss, PDA/pulmonary artery stenosis, “blueberry muffin” lesions | Confirm virologically; supportive specialty care and infection-control follow-up |
| Syphilis | Rhinitis, rash including palms/soles, hepatosplenomegaly, anemia/thrombocytopenia, bone disease; may be asymptomatic | Compare maternal treatment/serology and infant exam/titer; penicillin regimen depends on evaluation and follow-up certainty |
| HSV | Vesicles may be absent; sepsis-like shock, hepatitis, encephalitis, seizure, eye/skin/mouth disease | Obtain surface/blood/CSF testing as indicated and begin IV acyclovir promptly when suspected |
Congenital infection can be present despite a well appearance at birth. Ensure definitive hearing, vision, neurodevelopmental, laboratory, and specialty follow-up appropriate to the pathogen.
Medication safety, infection control, and follow-up
Before administering antibiotics or acyclovir, verify weight, gestational and postnatal age, renal function, dose interval, vascular access, culture time, and compatibility. Monitor urine output and creatinine with aminoglycosides and follow level-monitoring policy. Acyclovir requires adequate hydration and renal surveillance. Ceftriaxone is generally avoided in neonates at risk for bilirubin displacement and in those receiving calcium-containing IV solutions; select the institution's neonatal cephalosporin alternative when one is needed.
Use standard precautions for all infants and add pathogen-specific isolation. Vesicular HSV lesions, draining congenital-syphilis lesions/secretions, rubella, and some CMV exposures require distinct precautions and staff counseling. Hand hygiene and central-line care prevent late-onset infection; do not separate a stable dyad reflexively when precautions and treatment can be delivered safely.
At discharge after infection or congenital-infection evaluation, identify who reviews every pending culture/PCR and how the family will be reached. Arrange hearing, eye, neurologic, developmental, liver/hematologic, and infectious-disease follow-up appropriate to the pathogen. Teach caregivers to seek urgent care for fever or hypothermia, breathing change, poor feeding, fewer wet diapers, unusual sleepiness, color change, or seizure.
Because maternal and infant records may separate after discharge, reconcile the maternal infection, GBS prophylaxis, rupture duration, cultures, placental findings, and neonatal medications in the handoff. State exactly what remains pending and the contingency for a positive result. This closed-loop transfer is especially important when the infant leaves before the maternal culture is final.
A 12-hour-old infant has hypothermia, grunting, mottling, lethargy, and leukopenia after prolonged membrane rupture. What is the priority?
A 2-day-old infant is evaluated for microcephaly, petechial rash, and intrauterine growth restriction. Head ultrasonography demonstrates pronounced intracranial calcifications concentrated specifically in the periventricular regions surrounding the lateral ventricles. Diagnostic evaluation confirms sensorineural hearing loss. Which maternal-fetal infection is responsible for this clinical presentation?
A well-appearing 39-week newborn was born 2.5 hours after the first dose of indicated maternal penicillin for GBS. How should the newborn be managed?