Maternal ABO blood group type B: a risk factor in the developement of neonatal group B streptococcal disease

In a prospective study of maternal genital colonization with group B streptococci (GBS) at the time of delivery, epidemiological data, including blood type (ABO group), were recorded for the 1,062 patients studied. Blood type B was found in a statistically significant higher proportion of patients colonized with GBS (28%) compared with the total population (16.4%) (P less than .005, X2 = 8.43). Women with blood type B were twice as likely to be colonized as those with types O or A. Hypotheses to explain this observation include the possibilities that GBS possess a B-like antigen, rendering parturients who lack anti-B antibody at increased risk for GBS colonization, or that GBS possess a receptor site for B surface antigens. One may speculate that a mutation toward an affinity for the human ABO blood group type B accounts for the advent of the group B Streptococcus as a significant perinatal pathogen.