554 - Late Onset Sepsis in the NICU: Differentiating CoNS From Other Bacteria and Negative Work-Ups

Poster Number: 554
Publication Number: 554.428

Blaine Traylor, Southern Illinois University School of Medicine, Springfield, IL, United States; Stella Udoetuk, Southern Illinois University School of Medicine, Matteson, IL, United States; Mohamed Ahamed, Southern Illinois University School of Medicine, Springfield, IL, United States; Ginger Darling, SIU School of Medicine, Springfield, IL, United States; Laura B. Vargas, Southern Illinois University School of Medicine, Springfield, IL, United States; Erin M. Bauer, Southern Illinois University School of Medicine, Springfield, IL, United States; Albert Botchway, Southern Illinois University School of Medicine, Springfield, IL, United States; Beau Batton, SIU SOM, SPRINGFIELD, IL, United States; Venkata S. Majjiga, Southern Illinois University School of Medicine, Chatham, IL, United States

Background: Coagulase-Negative Staphylococcus (CoNS) is a gram-positive commensal skin organism that rarely causes clinically significant infection in healthy children and adults. In VLBW neonates, CoNS accounts for 28% to 54% of late-onset sepsis (LOS) cases and can both prolong hospital length of stay and increase the risk of neurodevelopment sequelae. Differentiating true CoNS infection from a contaminant can be a challenge, the NICHD partly bases this differentiation on the length of antibiotic therapy which varies substantially across NICUs. A better understanding of clinical variables for CoNS LOS as compared to pathological organisms or a negative evaluation may improve antibiotic stewardship without increasing the risk of untreated true CoNS infection.

Objective: To determine factors differentiating CoNS bacteremia from other pathological organisms and those with a negative blood culture NICU patients undergoing a LOS evaluation.

Design/Methods: Retrospective chart review of all LOS evaluations at a level III NICU (ADC: 40, >700 annual admissions) over a ~10 year period through 4/2021. LOS evaluations were classified into 3 groups: negative blood culture, CoNS bacteremia (definite or probable infection based on NICHD criteria) and pathologic organisms. Demographic data, risk factors for infection, clinical symptoms, and laboratory results between the groups were analyzed using the Kruskal-Wallis test for continuous variables and Chi square for categorical variables (p < 0.05 considered significant).

Results: There were 756 LOS evaluations: 129 (17%) blood cultures grew bacteria, of which 62 (48%) grew CoNS. The median time to positivity was 17 hours for pathologic bacteria and 26 hours for CoNS (p = 0.001). Demographic data and factors contributing to bacteremia are presented in table 1. Infants with pathologic bacteremia had a lower BW and GA at birth. Table 2 shows symptoms at LOS evaluation. Apnea/bradycardia were more common with CoNS bacteremia group, while lethargy and metabolic acidosis were more common with pathologic bacteremia. Lab data at LOS evaluation is presented in table 3: CRP was significantly higher with pathologic bacteremia when compared to CoNS and negative culture.Conclusion(s): For NICU patients undergoing a LOS evaluation, apnea/bradycardia are more common with CoNS bacteremia, while lethargy and metabolic acidosis are more common with pathologic bacteremia and CRP increases across a continuum from negative blood culture to CoNS bacteremia to pathologic bacteria. This data can assist in designing future investigations intended to differentiate a true CoNS infection from a contaminant.
Jan 2022 CV Blaine Traylor.pdf
Table 2.Symptoms at LOS evaluation.