You sound urgent so I dug out my old (3rd ed.) Ruth Lawrence and found the
references for the 2 letters I referred to in my previous posts:

Author:        Schreiner-R-L.  Coates-T.  Shackelford-P-G.
Title:         Possible breast milk transmission of group B streptococcal
               infection [letter]
Source:        J-Pediatr.  1977 Jul.  91(1).  P 159.
Journal Title: JOURNAL OF PEDIATRICS.

Author:        Kenny-J-F.
Title:         Recurrent group B streptococcal disease in an infant
        associated with the ingestion of infected mother's milk [letter]
Source:        J-Pediatr.  1977 Jul.  91(1).  P 158-9.
Journal Title: JOURNAL OF PEDIATRICS.

Lawrence differentiates between early onset group B strep infections
(transmission occurs in utero), and late onset ("after the 4th day of
life, due to person-to-person contact").  She says early onset "is
associated with respiratory distress, apnea, shock and pneumonia.  Late
onset GBS is usually manifest as meningitis or osteomyelitits."  According
to Lawrence, penicillin is the treatment of choice.  (I'm not in my
office; I'm at home reading from the 1989 edition, mind you).

About the 2 cases reported in the Journal of Pediatrics, Lawrence says:
"It is not clear yet whether the transmission is mother to baby or the
reverse.  When a breastfed infant becomes infected, it is appropriate to
culture the milk, and consider treating the mother as well."

I know this doesn't exactly answer your question, but it helps a bit I
hope.

Ginna Wall, MN, IBCLC, Lactation Services Coordinator
University of Washington Medical Center, Mailbox 356153
1959 NE Pacific Street, Seattle WA 98195
Voicemail: (206)548-6368, Fax: (206)548-7665