Table 3.
Effect of ST/LA on adhesion† of EIEC to Caco-2 cell monolayers
| Time after EIEC addition (h) | |||||
| Probiotic treatment | Ratio of MOI‡ (ST/LA:EIEC) | 1 | 2 | 3 | Significance |
| None | N/A | 24 (3) | 27 (1) | 17 (5) | — |
| Live ST/LA 1 h prior to EIEC | 2:1 | 6 (2) | 5 (1) | 5 (2) | ** |
| 20:1 | 2 (1) | 1 (1) | 0 | *** | |
| 200:1 | 1 (1) | 0 | 0 | *** | |
| Live ST/LA simultaneous with EIEC | 2:1 | 19 (4) | 21 (4) | 24 (3) | NS |
| 20:1 | 15 (3) | 17 (2) | 11 (5) | NS | |
| 200:1 | 5 (1) | 7 (3) | 5 (1) | ** | |
| Live ST/LA 1 h after EIEC | 2:1 | 22 (5) | 29 (3) | 25 (2) | NS |
| 20:1 | 20 (4) | 23 (1) | 22 (3) | NS | |
| 200:1 | 21 (5) | 22 (2) | 23 (1) | NS | |
| ST/LA (antibiotic killed) 1 h prior to EIEC | 2:1 | 10 (2) | 9 (1) | 10 (1) | ** |
| 20:1 | 7 (1) | 7 (1) | 8 (1) | ** | |
| 200:1 | 3 (1) | 3 (2) | 3 (1) | ** | |
| ST/LA (antibiotic killed) simultaneous with EIEC | 2:1 | 18 (2) | 19 (1) | 18 (1) | * |
| 20:1 | 16 (1) | 16 (2) | 15 (1) | * | |
| 200:1 | 5 (1) | 7 (2) | 5 (1) | ** | |
| ST/LA (heat inactivated) 1 h prior to EIEC | 2:1 | 22 (1) | 25 (2) | 23 (2) | NS |
| 20:1 | 20 (1) | 23 (1) | 20 (1) | NS | |
| 200:1 | 21 (2) | 20 (2) | 20 (1) | NS | |
| ST/LA sp medium§ simultaneous with EIEC | 25 (2) | 23 (2) | 22 (1) | NS | |
†Mean (SEM) of adherent EIEC per 100 cells examined in 20 random microscopic fields, for four experiments in duplicate.
‡MOI=multiplicity of infection. EIEC was applied at 50:1 throughout.
§ST/LA spent medium from 48 hour cultures was filtered, lyophilised, and concentrated 10×.
*p<0.05, **p<0.01, ***p<0.001, data sets significantly different from EIEC with no probiotics (by repeated measures ANOVA).
ST/LA, Streptococcus thermophilus and Lactobacillus acidophilus; EIEC, enteroinvasive Escherichia coli.