agalactiae group bstreptococcus agalactiae bstrep agalactiae group bgroup b strep gram positive cocciagalactiae gr bstreptococcus agalactiae treatmentpositive for streptococcus agalactiaestreptococcus agalactiae transmissionstreptococcus agalactiae meningitisstreptococcus agalactiae pregnancystreptococcus agalactiae antibioticsstreptococcus agalactiae infection