Identification of sepsis in neonates following maternal antibiotic therapy.

To examine the value of current diagnostic tests identifying neonatal sepsis related to intrapartum treatment with antibiotics, we reviewed the charts of 219 mother-infant pairs, of which 139 mothers received intrapartum antibiotics (group 1) and 80 mothers did not (group 2). When compared with group 2 infants, group 1 infants had fewer positive blood cultures (4.3% vs 20%, P < 0.003), blood cultures positive for group B streptococci (GBS) (P < 0.001), and positive urine GBS latex agglutination (LA) tests (P < 0.001). Although the sensitivity of the white blood cell count (WBC) was 81%, the specificity was < 60% in both groups. The specificity of the urine GBS LA test was 92%. These results suggest (1) the WBC will neither confirm nor rule out neonatal septicemia; (2) blood cultures are indicated in suspected neonatal sepsis even if there was maternal intrapartum treatment with antibiotics; and (3) a urine GBS LA test is a useful adjunct in the diagnosis of neonatal GBS septicemia.