Abstract 1325

Since implementation of the 1996 CDC recommendations for prevention of perinatal GBS we have noted a rise in intrapartum antibiotic usage. GBS late onset disease (GBS-LOD), with onset >7 days, is infrequent but well described among term and premature infants, even in those treated earlier with antibiotics (reinfection or relapse). In the past 12 months (Oct 1, 1997-Sept 30, 1998) we have documented 4 cases of culture positive GBS-LOD. We describe these cases and speculate as to the etiology of this late infection. Of the 549 NICU admissions during the study period, 69 were <1500 grams at birth (12.5%). All infants with GBS-LOD were identified by review of positive blood, CSF, or ETT aspirates during that period. Antenatal, birth, and hospital records were reviewed. Four cases (4/69, 5.8% of infants <1500 grams) were identified-2 male/2 female, one triplet, and three singletons, all AGA. All mothers had intrapartum antibiotic treatment and celestone. One of 3 placentas had evidence of chorioamnionitis on pathology. One woman with normal placental pathology had a GBS positive urine culture earlier in her pregnancy. Three women were GBS status negative or unknown. Gestational age ranged from 25-29 weeks (mean 27) with birth weights between 755-1270 grams (mean 983). All infants received initial antibiotic treatment (ampicillin and gentamicin) after birth for 3-5 days, with negative culture results. Age of GBS-LOD was 9-44 days (mean 25). GBS was cultured from blood in 3, blood and CSF in 1, and tracheal aspirate in one case. All survived. Previously published results from our NICU over 10 years (1983-92) reported no cases of GBS-LOD (PIDJ 1994;13:1098). There has been no change in neonatal infectious treatment practices, nor clustering of cases. All breast milk cultures were negative for GBS. We speculate that the combined use of antenatal antibiotics and corticosteroids may have contributed to GBS-LOD by supression but not elimination of perinatal acquisition of GBS.