Episode Details

Episode 162: Early-Onset Sepsis      

Dr. Kooner explains how to diagnose early-onset sepsis by using clinical evaluation and clinical tools. Dr. Schlaerths describes the signs and symptoms of sepsis in neonates, and Dr. Arreaza adds comments about GBS bacteriuria.  

Written by Lovedip Kooner, MD, editing Hector Arreaza, MD, and comments by Katherine Schlaerth, MD. Rio Bravo Family Medicine Residency Program.

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Introduction:

Neonatal sepsis is defined as pathogenic bacterial growth from blood or cerebral spinal fluid culture within the first 28 days of life. Neonatal sepsis can be divided into two categories: early-onset sepsis (EOS) and late-onset.  EOS is neonatal sepsis within 72 hours or 7 days after birth, depending on the specialist. 

How common is early-onset sepsis (EOS)?

According to the CDC, the infant mortality rate rose for the first time in 20 years in the USA. In the U.S., the incidence of EOS is 0.5 in 1,000 live births and carries a mortality rate of about 3%. 

What causes EOS?

Most infections are due to ascending lower vaginal tract flora. Other causes include intra-amniotic infections and maternal hematogenous spread of systemic infections. 

Group B streptococcus (S. agalactiae) accounts for about 1/3 of the infectious organisms, followed by E. coli which accounts for about 1/4, and Viridans streptococci account for about 1/5 of infections. Cases of E. coli are seen more often with prolonged rupture of membranes and intrapartum antibiotic exposure. Other notable infections are Listeria monocytogenes, coagulase-negative staphylococci (CoNS), herpes simplex virus, and enteroviruses. 

The role of GBS.

Approximately 30% of women have vaginal and rectal GBS colonization and 50% will transmit it to the newborn. Without maternal antibiotic treatment, 1-2% of those infants will develop EOS. The American College of Obstetricians and Gynecologists (ACOG) recommends universal culture-based screening for GBS at 36-37 weeks and 6 days regardless of mode of delivery. 

GBS bacteriuria: Treat it (symptomatic and asymptomatic) if >105 CFU/mL. Do not treat it in asymptomatic patients if GBS <105 CFU/mL. In any case, do not perform GBS screening in the third trimester in patients with GBS-positive urine culture earlier in pregnancy.

Intrapartum antibiotic prophylaxis for GBS.

The indications for intrapartum antibiotic prophylaxis for GBS EOS are: previous neonate with invasive GBS disease, positive GBS culture unless C-section is performed before rupture of membranes, GBS bacteriuria at any point during the current pregnancy.

If GBS status is unknown: At least one of the following criteria must be met: prematurity, rupture of membranes >18 hours, intrapartum fever, or GBS positive in previous pregnancy.

Nucleic acid amplification test: NAAT in pregnancy is not recommended to determine colonization status. However, if NAAT is obtained in the intrapartum period, give IAP if positive. But, you must also give IAP if negative + mentioned risk factors (<37 weeks, PROM >18h, Maternal fever >100.4F)

What is considered adequate intrapartum antibiotic prophylaxis? 

Penicillin and ampicillin are the recommended antibiotics for prophylaxis. Cefazolin can be given if there is a penicillin-allergy with a low risk for anaphylaxis. Clindamycin and vancomycin are reserved for cases of maternal penicillin allergy.