Clonal variability of group B Streptococcus among different groups of carriers in southern Israel

A high prevalence of maternal group B Streptococcus (GBS) carriage and an extremely low incidence of invasive neonatal disease have been reported from southern Israel. In order to obtain insight into this discrepancy, this study was performed to determine the population structure of GBS from asymptomatic pregnant women living in this area. Seventy-two strains from maternal GBS carriers were characterized using multilocus sequence typing (MLST). Epidemiologic characteristics of the carriers and their newborns, including demographic variables, obstetric status, and general health parameters, were collected by means of a postpartum interview and a review of the relevant medical records. The MLST analysis grouped the bacteria into six different lineages (clonal complexes). Lineage ST-2 was prevalent among Bedouin-Arabs (p=0.01) and lineage ST-22 among Jews (p=0.001). Lineage ST-17 was prevalent among carriers who emigrated after 1997 from western nations of the former USSR (p