To study the serotype distributions of group B streptococci (GBS) isolated from blood and cerebrospinal fluid and from the genital tract of pregnant women and to investigate any possible relation between serotype, age and clinical manifestation.
Methods
Invasive strains were collected from 1988 to 1997 and genital strains from 1995 to 1996. Strains of GBS were serotyped with coagglutination. Clinical data were obtained from hospital notes.
Results
A total of 144 invasive strains, 78 from neonates and infants and 66 from adults, were serotyped. The most common isolates from neonates and infants were types III (62%), Ia (18%), and V (9%). The most common isolates from adults were types III (29%), Ib (23%), V (21%) and II (15%). A majority of the adults (94%) had an underlying medical condition. The most common serotypes of the 114 strains isolated from the genital tract of pregnant women were types III (32%), V (22%), Ia (13%), Ib (13%) and II (11%).
Conclusions
Serotype III was the single most frequent GBS isolate from infants and adults. Serotype V, which appeared first in 1992, was the third most frequent isolate. A vaccine containing five GBS capsular polysaccharides appears to be appropriate for the Swedish population.
