Evaluation of Microbial Causes of Early Onset Sepsis in the Neonatal Intensive Care Unit

Abstract Corresponding Author Sruti Kalla, sruti.kalla@sanfordhealth.org Funding None. Conflict(s) of Interest None. Background Many neonates admitted to the Neonatal Intensive Care Unit (NICU) require multiple interventions, including antibiotic therapy. Our project was driven by the need to optimize antibiotic use in early onset sepsis (onset during days 0-7 of life), particularly given the changing incidence of infections, the rise of antibiotic resistance, and the emerging antibiotic shortages in the United States. These challenges prompted an investigation into the microbiological profile of neonates in the NICU, aiming to identify the most common pathogens, antibiotic usage patterns, resistance trends, clinical outcomes, and potential complications. Methods A retrospective chart review was conducted of neonates admitted to the Sanford Children’s Boekelheide NICU between 1/1/2021 and 4/15/2024 who had either a positive blood culture or received empirical antimicrobial therapy (ampicillin, gentamicin, ± cefotaxime) in the first seven days of life. Chart review included maternal characteristics, demographics, microbiological profile of positive cultures, antibiotic choice and duration, and clinical outcomes. Results During the study period, 2202 neonates had blood cultures obtained for evaluation of early onset sepsis. Forty nine neonates had either a positive blood culture or received antibiotics in the first week of life. Neonates ranged in gestational age from 22 to 40 weeks 12 (25%) ≥ 37 weeks, 20 (41%) ≥ 34 weeks, 13 (27%) 28 weeks and 30 (61%) were male. Nine mothers (18%) were GBS positive (7 treated with at least 2 doses of ampicillin) and 9 (18%) had unknown GBS status. Culture results are available in Table 1. Discussion Based on our results, it is evident that there is a high rate of culture positivity, underscoring the importance of antibiotic stewardship to guide optimal treatment. Additionally, the high incidence of antibiotic use in culture-negative patients highlights the need for further research into effective antibiotic regimens and the use of defined biomarkers to support antibiotic discontinuation, especially in neonates presenting with nonspecific clinical symptoms. There was some resistance to ampicillin noted, although only one infant had resistance to both empirical antibiotic agents. There is significant potential for research in this challenging area to establish the right balance between testing, optimal antibiotic coverage, favorable outcomes, and the prevention of antibiotic resistance. Such research could lead to improved strategies that minimize unnecessary antibiotic use, ensure effective treatment, and reduce long-term health risks for neonates.