Digestive exophagy of biofilms by intestinal amoeba and its impact on stress tolerance and cytotoxicity

Eva Zanditenas, Meirav Trebicz-Geffen, Divya Kolli, Laura Domínguez-García, Einan Farhi, Liat Linde, Diego Romero, Matthew Chapman, Ilana Kolodkin-Gal, Serge Ankri

Research output: Contribution to journalArticlepeer-review


The human protozoan parasite Entamoeba histolytica is responsible for amebiasis, a disease endemic to developing countries. E. histolytica trophozoites colonize the large intestine, primarily feeding on bacteria. However, in the gastrointestinal tract, bacterial cells form aggregates or structured communities called biofilms too large for phagocytosis. Remarkably, trophozoites are still able to invade and degrade established biofilms, utilizing a mechanism that mimics digestive exophagy. Digestive exophagy refers to the secretion of digestive enzymes that promote the digestion of objects too large for direct phagocytosis by phagocytes. E. histolytica cysteine proteinases (CPs) play a crucial role in the degradation process of Bacillus subtilis biofilm. These proteinases target TasA, a major component of the B. subtilis biofilm matrix, also contributing to the adhesion of the parasite to the biofilm. In addition, they are also involved in the degradation of biofilms formed by Gram-negative and Gram-positive enteric pathogens. Furthermore, biofilms also play an important role in protecting trophozoites against oxidative stress. This specific mechanism suggests that the amoeba has adapted to prey on biofilms, potentially serving as an untapped reservoir for novel therapeutic approaches to treat biofilms. Consistently, products derived from the amoeba have been shown to restore antibiotic sensitivity to biofilm cells. In addition, our findings reveal that probiotic biofilms can act as a protective shield for mammalian cells, hindering the progression of the parasite towards them.

Original languageEnglish
Article number77
Pages (from-to)77
Journalnpj Biofilms and Microbiomes
Issue number1
StatePublished - 9 Oct 2023


  • Amoeba
  • Animals
  • Biofilms
  • Entamoeba histolytica/metabolism
  • Gastrointestinal Tract
  • Humans
  • Mammals
  • Phagocytosis

All Science Journal Classification (ASJC) codes

  • Applied Microbiology and Biotechnology
  • Biotechnology
  • Microbiology


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