DOI: 10.147042022/nq.20.8.NQ44954

Protective effect of Lactobacillus caseiand Lactobacillusfermentum cell-free supernatants against verotoxin 1 ofE. coli O157

Mustafa Attiyah Hadid, AbdulwahidB. Al-Shaibani, Mohammad M. F. Al-Halbosiy

Abstract

Verotoxin 1 (VT1) or Shiga-like toxin 1 (Stx-1) is an AB5 holotoxin with a potent inhibitor of protein synthesis and it is one of the major virulence factors of enterohemorrhagicEscherichiacoli (EHEC). This study is aimed to investigate the inhibitory effect of some lactic acid bacteria against the cytotoxicity of verotoxin 1. Cytotoxicity of verotoxin 1 (VT1) on the NCM425 cell line was evaluated with and without the presence of Lactobacilluscasei (Lc) and Lactobacillusfermentum (Lf) cell-free supernatants using 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT ) assay. Results indicated that VT1 exhibited a cytotoxic impact on NCM425 which was in a dose-dependent manner. The cytotoxic effects of VT1 were lessened by probiotic bacteria's cell-free supernatants at 25 and 50 µg/ml concentrations. No significant difference was recorded between the protective effect of Lc and Lf against VT1. In conclusion, L. casei and L. fermentum cell-free supernatants can suppress VT1- mediated cytotoxicity and promote NCM425 survival. The cell-free supernatants of L. caseiand L.fermentum may be added to a wide range of foods and employed as additives to reduce VTmediated cytotoxicity.

Keywords

Cell toxicity; Lactobacillus casei; Lactobacillus fermentum;probiotics; verotoxin 1

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