No, that is incorrect - the FALSE statement is:

Mutans streptococci are present in the mouths of infants at birth

You'll recall that Mutans streptococci are only present in the mouths of infants following the eruption of teeth. MS cannot colonize within the mouth without hard surfaces.

The infant acquires MS from his/her mother through frequent and intimate contact, such as that pictured. It has been demonstrated that children whose mothers had high levels of MS tend to become infected with this bacteria during a discrete period of time, or "window of infectivity."