441 - Improved Detection of Neonatal Early-Onset Sepsis Pathogens Using Fetal Umbilical Venous Blood (FUVB) Cultures

Publication Number: 2429.441

Fayez Bany-Mohammed, University of California, Irvine, Irvine, CA, United States; Cherry Uy, University of California, Irvine, School of Medicine, Orange, CA, United States; Robin Koeppel, University of California, Irvine Health, Orange, CA, United States

Background: Early-onset sepsis (EOS) is a major cause of neonatal morbidity and mortality. Fetal umbilical venous blood (FUVB) cultures, obtained from the placenta immediately after delivery, may serve as a useful alternative or adjunct to infant (INF) blood cultures

Objective: Evaluate the diagnostic accuracy and utility of paired FUVB and INF blood cultures for EOS

Design/Methods: We conducted a paired-sampling blood culture (BCX) study in a tertiary NICU over 52 months. Trained NICU nurses collected FUVB culture within 20 minutes after delivery, and infant BCX was obtained per standard of care. Demographics, risk factors, laboratory studies, and placental histopathology were collected. True-positive BCX were defined by 1) Time to positivity < 48h; 2) isolated microorganism is typically associated with EOS; 3) culture grew ≤2 bacteria; 4) Inflammatory markers and/or placental histopathology showing chorioamnionitis and/or funisitis; and 5) Clinical picture compatible with EOS

Results: During the study period, 2615 infants out of 11704 deliveries were admitted to the NICU; 1372 (52.4%) were evaluated for EOS, including 1198 (45.8%) who received antibiotics within 6 h. Paired BCXs were collected in 557 infants (40.5%), resulting in 38 positive cultures: 32 from FUVB alone, 3 from INF blood, and 3 from both. Gestational age ranged from 22w5d – 43w0d, and birthweight from 390 – 4690 g. Twenty of the 32 FUVB-only cultures met all criteria for true-positive BCX; infants received a full antibiotic-tailored course, except for one who died. Pathogens isolated were E. coli (9; 45%), Enterococcus faecalis (4; 20%), Group B streptococcus (2; 10%), Strep anginosus (2, 10%), and Klebsiella pneumoniae, Proteus Mirabilis, and Bacteroides fragilis (1 each, 5%). 7 of 32 (1.3%) FUVB-only cultures were deemed contaminants. In the remaining five FUVB-only cultures, single organisms typical of EOS grew within 24 h (3 E. coli, 2 Strep viridans); however, the patients’ clinical courses, laboratory evaluations, and/or placental histopathology were not consistent with EOS, and they were treated with limited antibiotic courses. It is unclear whether these 5 cases represent contamination or transient bacteremia. Diagnostic accuracy and utility of FUVB culture for clinically relevant culture-proven EOS showed: sensitivity 88%, specificity 99%, positive predictive value 82%, and negative predictive value 99%, as compared to 23%, 100%, 100%, and 96%, respectively, for INF blood cultures.

Conclusion(s): FUVB cultures are useful for evaluating neonatal EOS, with greater sensitivity than INF cultures and with a relatively low contamination rate

Diagnostic utility of FUVB and infant blood cultures in detection of neonatal EOS
Diagnostic utility of FUVB.pdf