welcome to health care magic
blood infection is nothing but septicemia
that means infection spread all over the body through blood...
it doesnot mean that infection came from mother...
a 3 month old baby infected means,may be because of your faulty practices like feeding the baby with cow or buffalo milk instead of mother's milk..try to avoid that give the baby only breast milk,,it will decreases the chances of getting diabetes
in the future to the baby..
normal wbc count
for infant is upto 15000 ..
consult a pediatrician
for further measures..hope you understand my suggestion,,