Perfil de Susceptibilidade Antimicrobiana de Bifidobacterium bifidum Bb12 e Bifidobacterium longum Bb46

Bifidobacterium constitutes the most recent group of bacteria used as dietetic adjunct presenting probiotic properties such as prevention and treatment of infectious intestinal disorder. An expected characteristic for the selection of a probiotic is its antibiotic sensibility discarding the possibility of resistance transmission in the digestive ecosystem and allowing the elimination of the biotherapeutic, if necessary. In this study, the susceptibility to antibiotics of two Bifidobacterium species was tested. Bifidobacterium bifidum Bb12 and Bifidobacterium longum Bb46 have been isolated from a commercial lyophilized preparation (DVS – Christian Hansen Lab., Horsholm, Denmark). Bacteroides fragilis ATCC 25285 was used as control. The following antibiotic classes were tested: b -lactam, lincosomide, macrolide, phenolic, glycopeptide, tetracycline and aminoglycoside. The susceptibility assays of the antibiotics were performed using the standard agar dilution method (NCCLS-2000), with some modification. After inoculation and incubation during 48 hours at 37oC, in an anaerobic chamber, the absence or presence of growth on the plates was observed. All the tests were realized in duplicate. The results showed that the both B. bifidum Bb12 and B. longum Bb46 were sensible to all of the antibiotics tested, and for all of the concentrations used, except to gentamicin. Concluding, the possibility of a transmission of antibiotic resistance from these probiotics to pathogenic bacteria can be considered to be low during the use of these biotherapeutics.