SEROTYPE DISTRIBUTION OF INVASIVE GROUP-B STREPTOCOCCAL ISOLATES IN MARYLAND - IMPLICATIONS FOR VACCINE FORMULATION

Invasive group B streptococcal (GBS) infection is a major health probl em among infants and adults. The formulation of GBS vaccines depends o n knowledge of the GBS serotype distribution, Serotype V GBS infection appears to have recently emerged, suggesting that the serotype distri bution changes over time. GBS isolates from 210 pediatric patients, 23 pregnant women, and 314 nonpregnant adults with invasive infection in Maryland were studied. The predominant serotypes from infants with ea rly-onset disease were as follows: serotype III, 38% of isolates; sero type la, 36%; serotype V, 13%; and serotype II, 11%, Although the majo rity (60%) of isolates among infants with late-onset infection were se rotype III, serotype Ia (23%) was also common. The predominant serotyp e among isolates from nonpregnant adult patients was serotype V, accou nting for 29% of the isolates. The serotype distribution differs betwe en pediatric patients and adults and is changing over time, The inclus ion of a relatively small number of serotypes in a GBS vaccine could p rovide protection against the vast majority of isolates.