Probable Community Acquisition of Group B Streptococcus in an Infant With Late-Onset Disease: Demonstration Using Field Inversion Gel Electrophoresis

The leading life-threatening neonatal pathogen in North America is group BStreptococcus(GBS).¹While early-onset disease has been shown to occur through vertical transmission of GBS from mother to infant, the mode of transmission in late-onset infection has not been clearly defined.¹,²Over the last 2 decades, studies of infants in newborn nurseries and neonatal intensive care units have demonstrated that horizontal (nosocomial) transmission of GBS occurs between infants and is responsible for the acquisition of GBS in some cases of late-onset disease. These studies provided epidemiologic data³⁻⁵and microbiologic evidence of the identity of GBS isolated from different patients.⁶⁻¹⁰ Knowledge regarding the natural history of colonization with GBS in the infant and child and the role of community acquisition of GBS in the pathogenesis of late-onset disease is incomplete.¹,⁴,¹¹,¹²We describe a case of late-onset GBS sepsis in a 2-month-old infant. The organism was