Newborn Antibiotic Exposures and Association With Proven Bloodstream Infection.

OBJECTIVES: To estimate the percentage of hospital births receiving antibiotics before being discharged from the hospital and efficiency diagnosing proven bloodstream infection.

METHODS: We conducted a cross-sectional study of 326 845 live births in 2017, with a 69% sample of all California births involving 121 California hospitals with a NICU, of which 116 routinely served inborn neonates. Exposure included intravenous or intramuscular antibiotic administered anywhere in the hospital during inpatient stay associated with maternal delivery. The main outcomes were the percent of newborns with antibiotic exposure and counts of exposed newborns per proven bloodstream infection. Units of observation and analysis were the individual hospitals. Correlation analyses included infection rates, surgical case volume, NICU inborn admission rates, and mortality rates.

RESULTS: The percent of newborns with antibiotic exposure varied from 1.6% to 42.5% (mean 8.5%; SD 6.3%; median 7.3%). Across hospitals, 11.4 to 335.7 infants received antibiotics per proven early-onset sepsis case (mean 95.1; SD 71.1; median 69.5), and 2 to 164 infants received antibiotics per proven late-onset sepsis case (mean 19.6; SD 24.0; median 12.2). The percent of newborns with antibiotic exposure correlated neither with proven bloodstream infection nor with the percent of patient-days entailing antibiotic exposure.

CONCLUSIONS: The percent of newborns with antibiotic exposure varies widely and is unexplained by proven bloodstream infection. Identification of sepsis, particularly early onset, often is extremely inefficient. Knowledge of the numbers of newborns receiving antibiotics complements evaluations anchored in days of exposure because these are uncorrelated measures.