Between 1991 and 1995, among 999 nonpregnant adult Maryland residents with
group B Streptococcus (GBS) isolated from a normally sterile site, 84 resid
ed in nursing homes (NHs). The age- adjusted annual incidence of GBS infect
ion (per 100,000 population) among those greater than or equal to 65 years
old was 72.3 for NH residents and 17.5 for community residents (relative ri
sk, 4.1; P < .001). Thirty-four case patients resided in 11 NHs with <great
er than or equal to>2 cases; 1 NH had 8 case patients within 22 months. Six
of 8 case patients from 3 NHs had serotype V GBS. Molecular subtyping of s
everal isolates identified 2 case patients in 1 NH with identical subtype p
atterns. NH residents have a markedly higher incidence of invasive GBS than
do community residents greater than or equal to 65 years old and may serve
as a target group for immunization when GBS vaccines become available. Fur
ther evaluation of intra-NH transmission of GBS is warranted.