Increased risk of group B streptococcal disease in twins.

Infants who are the product of multiple births comprise a newly defined group of patients at increased risk for the development of invasive, group B streptococcal infection. This report summarizes the clinical and bacteriological features of 11 sets of twins and one set of triplets in which one (nine sets) or more (three sets) infants had proved early- or late-onset group B streptococcal infection. Reasons for the enhanced susceptability of index patients and their siblings are discussed. On the basis of these observations, an emperical approach is proposed for the treatment of the apparently noninvolved sibling of a twin with invasive group B streptococcal infection.