Study of the mechanism involved in the protective effect of Lactiplantibacillus plantarum CIDCA 83114 on shiga toxin (Stx)-producing Escherichia coli (STEC) pathogenicity in vitro

CANCINO C D; CARPINTERO Y M; BERNAL A M; SOSA F N; RAMOS M V; ABRAHAM A G; GARROTE G L; PALERMO M S; FERNANDEZ BRANDO RJ

Otro; Reunión anual de la Sociedad Argentina de Inmunología (SAI 2023; 2023

Shiga toxin (Stx)-producing Escherichia coli (STEC) O157:H7 is a foodborne pathogen, which can lead to the life-threatening Hemolytic Uremic Syndrome (HUS). There is no treatment available in order to reduce HUS outcome up to date. We previously showed that the probiotic strain Lactiplantibacillus plantarum CIDCA 83114 (CIDCA 83114) completely inhibits STEC growth in vitro when co-culturing both bacterial strains for 24h in ratios 1:1, 1:10 and 1:100 (STEC: CIDCA 83114). Besides, CIDCA 83114 reduces STEC adhesion to Caco-2 cells by an exclusion mechanism. In the present work we aim to delve into the mechanism of CIDCA 83114 on the pathogenic potential of a clinically isolated STEC strain in vitro. We tested EHEC growth at 6 h of co-culture with CIDCA 83114 in ratios 1:1, 1:10 and 1:100 (STEC: CIDCA 83114). We quantified lactate concentration by a colorimetric assay and pH values in all the EHEC:CIDCA 83114 ratios tested at 6 and 24 h. We also used conditioned media obtained by culturing CIDCA 83114 and then reproduced the lactate concentrations and pH values to that of the co-culture treatments. We also quantified TGFᵦ and IL-8 mRNA levels by RT-qPCR in Caco-2 cells after infection with EHEC and CIDCA 83114 in ratios 1:1 and 1:100 (STEC: CIDCA 83114).We observed EHEC growth inhibition when co-cultured with CIDCA 83114 at 6 h in a 1:100 ratio (p