Predictors of positive cerebrospinal fluid cultures in infants with bacteremia.

BACKGROUND Meningitis causes substantial morbidity and mortality in hospitalized infants. There is no consensus on the ability of blood cultures to predict results from cerebrospinal fluid (CSF) cultures in hospitalized infants. METHODS We used the Pediatrix Medical Group database of infants discharged from 333 neonatal intensive care units between 1997 and 2011. We identified all infants with a positive blood culture and a CSF culture obtained within 3 days. We evaluated the odds of a concordant blood-CSF culture pair, controlling for severity of illness, organism type, gestational age, day of blood culture and blood-CSF culture pairing, exposure to CSF-penetrating antibiotics and the presence of a ventriculo-peritoneal shunt. RESULTS We identified 8839 infants with 9408 blood-CSF culture pairs. Serratia marcescens (24/227, 11%) and Streptococcus pneumoniae (7/64, 11%) had the highest proportion of concordant blood-CSF culture pairs. The presence of a ventriculo-peritoneal shunt, as well as timing of the CSF culture on the same day as the blood culture, were associated with increased odds of blood-CSF culture pair concordance-odds ratio = 3.87 (95% confidence interval; 2.59-5.78) and 6.11 (2.81-13.24), respectively. CONCLUSION The frequency of blood-CSF culture pair concordance is related to organism type and to the timing of the CSF culture in relation to the blood culture.