[Group B beta-hemolytic Streptococcus: study on colonization of mother-neonate couples observed in January-May 1988 at the obstetrics and gynecology unit and the neonatal section at the Pistoia Hospital].

In a previous study, carried out on women at delivery recovered at the obstetric ward of the Pistoia Hospital, we noted a high incidence of group B Streptococci cultured from vaginal site. Because group B streptococcal infection is very serious in neonates we decided to examine the frequence of vertical and horizontal transmission among the mother-neonate couples. We have also compared their rate of colonisation by doing rectal and vaginal swabs on women and rectal, vaginal and external auditory canal swabs on babies. In fact we known that infants moderately to heavily colonised with group B Streptococci at birth, appear to have a significant higher risk of developing serious disease than do infants only lightly colonised. In our work we haven't observed any acute group B streptococcal infection, but we have identified 18 couples mother-neonate colonised by the same group B Streptococci serotype, which is proof of an easy vertical transmission of group B Streptococci whilst horizontal transmission is very rare (only one case).