Abstract:[Background] Caused by the abuse of antibiotics, the rapid emergence of resistant bacteria is occurring worldwide. For Bifidobacterium, the probiotic property has been emphasized, while there is a paucity of research on the antibiotic resistance. [Objective] To detect the antibiotic resistance of Bifidobacterium pseudocatenulatum isolated from the feces of mothers and infants and to explore the source of resistant strains in infant gut. [Methods] The resistance of 48 strains of B. pseudocatenulatum isolated from the feces of mothers and infants to 14 antibiotics was determined by the minimum inhibitory concentration method, and the resistance of strains isolated from different families was compared. [Results] All the 48 strains were resistant to tetracycline, chloramphenicol, neomycin, and ciprofloxacin, and 98%, 80%, 78%, 63%, 59%, 43%, 16%, 14%, 6%, and 2% of the strains were resistant to kanamycin, rifamycin, clindamycin, trimethoprim, erythromycin, gentamicin, streptomycin, vancomycin, ampicillin, and linezolid, respectively. There were no significant differences in antibiotic resistance between the isolates from mothers and infants, and isolates from the same family had similar antibiotic-resistant phenotypes. [Conclusion] The B. pseudocatenulatum isolated from feces of mothers and infants were resistant to a variety of antibiotics. The resistant strains in infant gut may be vertically transmitted from the mother's gut.