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Updated: Aug 7, 2026
A Neonatal Imaging Model of Gram-Negative Bacterial Sepsis
Published on: August 12, 2020
Evaluating the near-term infant for early onset sepsis: progress and challenges to consider with 16S rDNA polymerase
Jeanne A Jordan1, Mary Beth Durso, Allyson R Butchko
1Department of Pathology, Magee-Women's Research Institute, 204 Craft Ave., Pittsburgh, PA 15213, USA. rsijaj@mwri.magee.edu
Insights
Early onset sepsis in neonates has high mortality. A rapid 16S rDNA polymerase chain reaction (PCR) test showed high specificity but missed some culture-proven sepsis cases, indicating caution is needed.
Area of Science:
- Neonatal Medicine
- Infectious Diseases
- Molecular Diagnostics
Background:
- Early onset sepsis in neonates, though rare, carries significant mortality and morbidity risks.
- Current diagnostic methods, like blood culturing, are slow, leading to prolonged broad-spectrum antibiotic use in infants.
- Maternal antibiotic prophylaxis and small infant blood volumes can compromise culture accuracy.
Purpose of the Study:
- To evaluate the utility of a 16S rDNA polymerase chain reaction (PCR) assay as a rapid diagnostic tool for early onset neonatal sepsis.
- To compare the performance of PCR against standard blood culturing methods in a near-term neonatal population.
Main Methods:
- A 16S rDNA PCR assay was implemented and compared to blood culturing for sepsis diagnosis.
- The study included 1,233 near-term infants admitted to the neonatal intensive care unit.
- Analytical specificity and negative predictive value of the PCR assay were assessed.
Main Results:
- The PCR assay demonstrated high analytical specificity (97.5%) and negative predictive value (99.2%) compared to blood cultures.
- However, the PCR assay failed to detect a notable number of sepsis cases confirmed by blood culture.
- These findings highlight limitations in the current sensitivity of the molecular assay.
Conclusions:
- While the 16S rDNA PCR assay shows promise with high specificity, its current sensitivity is insufficient for sole diagnosis of neonatal sepsis.
- Further improvements in sample collection and preparation techniques are crucial to enhance the analytical sensitivity of molecular amplification tests.
- A cautious approach is recommended when considering molecular tests for diagnosing early onset neonatal sepsis.
Abstract:
Although the rate of early onset sepsis in the near-term neonate is low (one to eight of 1,000 cases), the rate of mortality and morbidity is high. As a result, infants receive multiple, broad-spectrum antibiotic therapy, many for up to 7 days despite blood cultures showing no growth. Maternal intrapartum antibiotic prophylaxis and small blood volume collections from infants are cited as reasons for the lack of confidence in negative culture results. Incorporating an additional, more rapid test could facilitate a more timely diagnosis in these infants. To this end, a 16S rDNA polymerase chain reaction (PCR) assay was compared to blood culturing for use as a tool in evaluating early onset sepsis. Of 1,751 neonatal intensive care unit admissions that were screened, 1,233 near-term infants met inclusion criteria. Compared to culture, PCR demonstrated excellent analytical specificity (1,186 of 1,216, 97.5%) and negative predictive value (1,186 of 1,196, 99.2%); however, PCR failed to detect a significant number of culture-proven cases. These findings underscore the cautionary stance that should be taken at this time when considering the use of a molecular amplification test for diagnosing neonatal sepsis. The experience gained from this study illustrates the need for changes in sample collection and preparation techniques so as to improve analytical sensitivity of the assay.
