TABLE 1.

In vitro transfer of bla genes between enterobacteria in the absence or presence of bifidobacteriaa

StrainTransfer of blaSHV-5 from K. pneumoniae CIP-104771 to E. coli K-12Transfer of blaCTX-M-15 from serovar Typhimurium CAM18 to E. coli K-12
Transfer frequencyTransconjugant count (log10)Decrease in transconjugant count (log10)Transfer frequencyTransconjugant count (log10)Decrease in transconjugant count (log10)
No bifidobacteria(42.02 ± 2.04) × 10−64.5 ± 0.3(44.04 ± 1.82) × 10−46.1 ± 0.1
B. pseudocatenulatum BS4(41.23 ± 1.03) × 10−64.3 ± 0.10.2(70.15 ± 9.26) × 10−45.9 ± 0.30.2
B. bifidum BS119(40.61 ± 6.50) × 10−64.3 ± 0.10.2(20.38 ± 1.12) × 10−45.8 ± 0.10.3
B. longum CUETM-89-215(0.06 ± 0.02) × 10−6*2.1 ± 0.3*2.4(0.38 ± 0.24) × 10−4*4.7 ± 0.1*1.4
B. bifidum CIP-56.7T(0.07 ± 0.01) × 10−6*2.3 ± 0.2*2.2(0.18 ± 0.04) × 10−4*3.9 ± 0.2*2.2
B. pseudocatenulatum CIP104168T(0.07 ± 0.01) × 10−6*1.9 ± 0.4*2.6(0.25 ± 0.17) × 10−4*4.0 ± 0.1*2.1
  • a Values represent the averages from a minimum of three experiments. The transfer frequency is the transconjugant counts relative to the donor counts after the mating period. *, P ≤ 1% in the Student test in comparison to values in the conjugations without bifidobacteria. Significant decreases in transconjugant counts are indicated in boldface.