Had to weigh in on this, being an old microbiologist!  Both
lactobacilllus and bifidobacterium are present in the GI tract of
humans.  They can both be present in the oral cavity, and are found in
abundance in the vagina.  Baby likely gets colonized from mom's vagina,
or hands.  It's gross to think about, but mom's intestines actually
provide an enormous number of bacteria, as does her vagina, mouth and
skin.

Baby gets colonized soon after birth with a host of "friendly" bacteria,
and we rely on this mechanism to protect the baby from less friendly
bugs.  Bacteria tend to settle in an environment that makes them happy,
and they tend to create their own environment - pH, oxygen, acid
by-products, etc., thus the predilection of a bacterium to a specific
site.

It would be hard to picture how readily bacteria are transferred from
person to person, without seeing it for yourself (where's that
microscope?), but again, we rely on this easy transmission to provide us
with happy bugs, and keep out the bad bugs.

IMHO, it is unlikely that colonization occurs through hematogenous
spread to the breast.  Usually, even friendly bugs in normally sterile
sites make us very sick, and the body doesn't allow it unless our immune
defenses are torn down.  Microbiologists have seriously looked at every
part of the body, and have a pretty good fix on what kind of bacteria
are present where, although there have been a few surprises in recent
years, concerning hard-to-grow bacteria in difficult environments.

I would think that the action of breast milk on a yeasty bottom would be
a sophisticated interplay of cellular defenses, pH, anti-inflammatory
actions, immunoglobulins, and all of those wonderful anti-infectious
factors that my feeble brain could not begin to name.

Denise Sweeney, RN, IBCLC

             ***********************************************
The LACTNET mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software together with L-Soft's LSMTP(TM)
mailer for lightning fast mail delivery. For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html