Interactions of Lactobacillus spp. and enteropathogenic Escherichia coli under in vitro and in vivo conditions.

In the present study, the effect of Lactobacillus spp. against enteropathogenic Escherichia coli 08:K88+Ent+ under in vitro and in vivo conditions has been compared and the effect of inoculation of Lactobacillus spp. upon the colonization of both the jejunum and ileum by enteropathogenic E. coli 08:K88+Ent+ in 9 gnotobiotic pigs has been observed. Under in vitro conditions, the strain Lactobacillus spp. showed the inhibition of 2.1 +/- 0.1 mm against enteropathogenic E. coli 08:K88+Ent+. Two days after the inoculation, the enteropathogenic E. coli 08:K88+Ent+, inoculated to the control group of gnotobiotic pigs (E), colonized the mucosa of both jejunum and ileum of gnotobiotic pigs at counts of 6.41 and 6.08 log 10/cm2, respectively. In experimental group (L-E), the counts of adhered enteropathogenic E. coli in the identical sections of the small intestine, following the inoculation by Lactobacillus spp., amounted to 6.35 and 6.43 log/cm2, respectively. In both groups, numbers of E. coli in the intestinal content of both jejunum and ileum were nearly the same (group E 9.03 and 9.31 log 10/ml; group L-E 8.97 and 9.11 log 10/ml). Two to five days after E. coli inoculation, Lactobacillus spp. counts adhered to the jejunal wall ranged from 5.4 to 6.49 log 10 cm2; in the ileum they ranged from 6.05 to 6.77 log 10 cm2. In the jejunal content, the lactobacilli counts ranged from 6.81 to 8.86 log 10/ml and in the ileum from 8.5 to 898 log 10/ml. Two days after the E. coli inoculation, the concentration of lactic acid in the content of jejunum in gnotobiotic pigs of the groups E and L-E was 16.3 mmol/l and 23.6 mmol/l, respectively. The concentration of acetic acid in the jejunum of the pigs of E and L-E groups was 15.9 mmol/l and 19.6 mmol/l, respectively. Similarly, the higher concentrations of both acids were found also in the ileum of the L-E pigs. The results obtained indicate that the used strain of Lactobacillus spp. which has been preventively inoculated to gnotobiotic pigs, did not prevent the adhesion of enteropathogenic E. coli 08:K88+Ent+ to the mucosa of both jejunum and ileum also despite of the demonstrated inhibitory effect against enteropathogenic E. coli under in vitro conditions and despite good adherent ability in vivo. In both groups of animals, the diseases with pronounced clinical signs as well as losses have occurred.