Episode 162: Early-Onset Sepsis

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. Specifically, clindamycin can be used only if GBS is known to be sensitive to clindamycin. Vancomycin must be used if GBS is resistant to clindamycin. Do not use erythromycin. You will Administered at least 4 hours before delivery.

IAP is believed to reduce neonatal GBS disease by: (1) temporarily reducing maternal vaginal GBS colonization; (2) preventing colonization of the fetus or newborn's surfaces and mucous membranes; and (3) achieving antibiotic levels in the newborn's bloodstream sufficient to surpass the minimum inhibitory concentration (MIC) for eliminating group B streptococci.

Diagnosis of EOS:

Clinical presentation: Tachycardia, tachypnea, temperature instability, supplemental oxygen requirement, and lethargy. Hypoglycemia should not be considered a sign of EOS.

Diagnosing early-onset sepsis is achieved through blood or cerebrospinal fluid (CSF) cultures. Not effective methods for diagnosing EOS include laboratory tests, such as a complete blood cell count or C-reactive protein (CRP), as well as surface cultures, gastric aspirate analysis, or urine culture.

Most infants will generally show signs of EOS GBS infection within the initial 24 hours of birth, with approximately 85% exhibiting symptoms during this timeframe.

Waiting for cultures and/or signs can delay lifesaving treatment.

Management:

According to the American Academy of Pediatrics (AAP), the management of term and late-term infants is undertaken via the clinical condition assessment, the categorical risk factor assessment, and the multivariate risk assessment. 

As a part of the 2015 AAP guidelines, the Categorical Risk Factor Assessment is more of an algorithmic approach based on the presence or absence of specific risk factor threshold values such as:

• Ill-appearing infant. 
• Mother diagnosed with chorioamnionitis.
• Mother GBS positive with inadequate intrapartum prophylaxis.
• ROM >18 hours.
• Birth before 37 weeks of gestation.

Antibiotics are not always needed, and they can even cause damage. Information taken from the American Academy of Pediatrics, “Management of Neonates Born at ≥35 0/7 Weeks’ Gestation With Suspected or Proven Early-Onset Bacterial Sepsis,” published on December 1, 2018:

(1) Any newborn infant who is ill-appearing or (2) when the mother has a clinical diagnosis of chorioamnionitis -> laboratory testing must be ordered, and empirical antibiotic therapy should be started.

(3) A mother who is colonized with GBS and who received inadequate intrapartum antibiotic prophylaxis, with a duration of ROM being >18 hours or birth before 37 weeks’ gestation -> laboratory testing should be ordered.

(4) A mother who is colonized with GBS who received inadequate IAP but with no additional risk factors -> observation in the hospital for ≥48 hours.

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Conclusion: Now we conclude episode number 162, “Early-onset Sepsis Introduction.” Dr Kooner explained the role of GBS in the pathophysiology of EOS, Dr. Schlaerth discussed the importance of clinical evaluation and Dr. Arreaza explained that GBS screening in the third trimester is not needed when there is a GBS positive urine culture early in pregnancy. Don’t miss part 2 of this discussion. By the way, we do not recommend using feces to prevent or treat sepsis, we just shared anecdotal information to end with a funny note.

This week we thank Hector Arreaza, Lovedip Kooner, and Katherine Schlaerth. Audio editing by Adrianne Silva.

Even without trying, every night you go to bed a little wiser. Thanks for listening to Rio Bravo qWeek Podcast. We want to hear from you, send us an email at RioBravoqWeek@clinicasierravista.org, or visit our website riobravofmrp.org/qweek. See you next week! 

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References:

1. Neonatal Early-Onset Sepsis Calculator by Kaiser Permanente, available at: https://neonatalsepsiscalculator.kaiserpermanente.org/.
2. Espinosa K, Brown SR. Neonatal Early-Onset Sepsis Calculator. Am Fam Physician. 2021;104(6):636-637.https://www.aafp.org/pubs/afp/issues/2021/1200/p636.html.
3. Puopolo KM, Benitz WE, Zaoutis TE; COMMITTEE ON FETUS AND NEWBORN; COMMITTEE ON INFECTIOUS DISEASES. Management of Neonates Born at ≥35 0/7 Weeks' Gestation With Suspected or Proven Early-Onset Bacterial Sepsis. Pediatrics. 2018 Dec;142(6):e20182894. doi: 10.1542/peds.2018-2894. PMID: 30455342. https://pubmed.ncbi.nlm.nih.gov/30455342/.
4. Briggs-Steinberg C, Roth P. Early-Onset Sepsis in Newborns. Pediatr Rev. 2023 Jan 1;44(1):14-22. doi: 10.1542/pir.2020-001164. PMID: 36587021. https://pubmed.ncbi.nlm.nih.gov/36587021/.
5. Flannery DD, Puopolo KM. Neonatal Early-Onset Sepsis. Neoreviews. 2022 Nov 1;23(11):756-770. doi: 10.1542/neo.23-10-e756. PMID: 36316253. https://pubmed.ncbi.nlm.nih.gov/36316253/.
6. Polin RA; Committee on Fetus and Newborn. Management of neonates with suspected or proven early-onset bacterial sepsis. Pediatrics. 2012 May;129(5):1006-15. doi: 10.1542/peds.2012-0541. Epub 2012 Apr 30. PMID: 22547779. https://pubmed.ncbi.nlm.nih.gov/22547779/.
7. Royalty-free music used for this episode: Good Vibes_Adventure Time by Simon Pettersson, downloaded on July 20, 2023, from https://www.videvo.net/