4. Discussion
B. bifidum YIT 4007 was derived from its progenitor strain YIT 4001
through consecutive screenings of resistant strains to erythromycin,
streptomycin, and neomycin to make B. bifidum YIT 4007 easily
distinguishable from other Bifidobacteria. Among bacterial antibiotic
resistance, some are associated with mobile genetic factors like
transposons and plasmids. These mobile factors have the potential to
transfer antibiotic resistance to other bacteria. Thus, it is very important
to elucidate the genetic characters of bacterial antibiotic resistance and
association of mobile genetic factors to review the potential of
horizontal transfer. Because B. bifidum YIT 4007 has been utilized to
produce the fermentedmilk beverage and ingested by consumers on the
daily basis, it is very important to elucidate the genetic basis of the
resistance to antibiotics of this strain.