Table 3.

Counts of viable and intact lactococci in stomach and duodenal contents by enumeration of erythromycin-resistant L. lactis and of L. lactis expressing GFP by fluorescence microscopy

CultureNo. of viable cellsa (mean ± SE)No. of viable cells in duodenum/no. in stomach (%)No. of intact cellsb (mean ± SE)No. of intact cells in duodenum/no. in stomach (%)
StomachDuodenumStomachDuodenum
Concentrated316,000 ± 17,000630 ± 200.2>500,000c 0d <0.01
Not concentrated620 ± 100120 ± 40201,680 ± 250420 ± 2025
  • a Viable count (106 CFU/ml of stomach or duodenum content) on M17 plus erythromycin, corrected by the dilution factor.

  • b Result of the count of GFP-positive fluorescent cells in 50 microscopic images, corrected by the dilution factor.

  • c Not countable with the standard dilution used in this experiment.

  • d No bacteria detected in 50 images.