Late-Onset GBS Lower Extremity Cellulitis in Premature Neonate with a GBS Negative Mother with Alternative Modes of Transmission: A Case Report

Abstract

Purpose: To report a case of cellulitis-causing late-onset Group B streptococcus (GBS) GBS in a neonate with a previously negative antenatal tested mother. This report aims to discuss the various transmission modes potentially causing this case of cellulitis, such as contaminated breast milk.  Case Description:  A preterm neonate, born via cesarean section (C-section) at 29 weeks gestation to a G1P0 mother with a negative GBS rectovaginal antenatal swab test, subsequently developed late-onset cellulitis in the lower extremity due to GBS 19 days later.  Methods: This is a retrospective case report followed by clinical observation, blood cultures, imaging, and antibiotic interventions.    Results: A neonate with left lower extremity cellulitis was found to be GBS positive from a previously negative antenatal GBS-negative mother.   Discussion: As GBS is a common pathogen of neonatal sepsis and less commonly cellulitis, testing rectovaginal fluids once may not be enough to prevent neonates and preterm infants from protecting against transmission. As there have been rare cases of GBS-contaminated breast milk, culturing and testing of breast milk should also be considered, especially in preterm infants.