Probiotic and enterohemorrhagic Escherichia coli: An effective strategy against a deadly enemy? (original) (raw)
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Treatment of in vitro enterohemorrhagic Escherichia coli infection using phage and probiotics
Journal of Applied Microbiology, 2016
Aims: To assay the combination of phage and probiotics against EHEC in vitro on infected Hep-2 cells. Methods and Results: Phage and probiotics treatments on EHEC O157:H7infected Hep-2 cells were assayed individually or combined. The effect of freeze-drying on phage and probiotic antimicrobial activity was also studied. While treatment with phage alone increased cell detachment caused by EHEC infection, the treatments with MM alone or in combination with phage proved to effectively diminish cell damage caused by EHEC infection. Combined treatment showed a decrease in apoptotic cell count of 57Á3% and a reduction in EHEC adhesion to cell monolayer of 1Á2 log CFU. The simultaneous use of phage and probiotics showed no antagonistic effect, and freeze-drying did not affect their antipathogenic activity. Conclusions: The combination of phage and probiotics has great potential for reducing the number of pathogens adhered to epithelial cells during EHEC O157:H7 infection and attenuating the cytotoxic effect derived from it. Further in vivo assays are needed for assessing the actual effectiveness of the treatment. Significance and Impact of the Study: This study presents a freeze-dried formulation of phage and probiotics capable of controlling EHEC infections and reducing epithelial cell damage in vitro.
Diarrheagenic Escherichia Coli and Probiotic Activity against Foodborne Pathogens: A Brief Review
2017
E. coli strains are naturally commensal bacteria that live in intestinal tract of humans and other mammals. Some strains are pathogenic and can cause disease, especially intestinal [2]. Diarrheagenic E. coli strains are classified into six categories, based in clinical syndromes, symptoms, epidemiology, O:H serotypes, virulence factors and interaction with in vitro cultivated cells [3]. All enteropathogenic E. coli types cause generally watery diarrhea as a common symptom. Most episodes of intestinal dysfunction are auto limited and solved in a few days, but some rare cases can progress to more severe disease [2,3].
Infection and Immunity, 2014
Enteropathogenic Escherichia coli (EPEC) is recognized as an important intestinal pathogen that frequently causes acute and persistent diarrhea in humans and animals. The use of probiotic bacteria to prevent diarrhea is gaining increasing interest. The probiotic E. coli strain Nissle 1917 (EcN) is known to be effective in the treatment of several gastrointestinal disorders. While both in vitro and in vivo studies have described strong inhibitory effects of EcN on enteropathogenic bacteria, including pathogenic E. coli , the underlying molecular mechanisms remain largely unknown. In this study, we examined the inhibitory effect of EcN on infections of porcine intestinal epithelial cells with atypical enteropathogenic E. coli (aEPEC) with respect to single infection steps, including adhesion, microcolony formation, and the attaching and effacing phenotype. We show that EcN drastically reduced the infection efficiencies of aEPEC by inhibiting bacterial adhesion and growth of microcolon...
International journal of medical microbiology : IJMM, 2015
Due to increased release or production of Shiga toxin by Enterohemorrhagic Escherichia coli (EHEC) after exposure to antimicrobial agents, the role of antimicrobial agents in EHEC mediated infections remains controversial. Probiotics are therefore rapidly gaining interest as an alternate therapeutic option. The well-known probiotic strain Escherichia coli Nissle 1917 (EcN) was tested in vitro to determine its probiotic effects on growth, Shiga toxin (Stx) gene expression, Stx amount and associated cytotoxicity on the most important EHEC strains of serotype O104:H4 and O157:H7. Following co-culture of EcN:EHEC in broth for 4 and 24 h, the probiotic effects on EHEC growth, toxin gene expression, Stx amount and cytotoxicity were determined using quantitative real time-PCR, Stx-ELISA and Vero cytotoxicity assays. Probiotic EcN strongly reduced EHEC numbers (cfu) of O104:H4 up to (68%) and O157:H7 to (72.2%) (p<0.05) in LB broth medium whereas the non-probiotic E. coli strain MG1655 h...
INSIGHTS FROM 100 YEARS OF RESEARCH WITH PROBIOTIC E. COLI
A century ago, Alfred Nissle discovered that intentional intake of particular strains of Escherichia coli could treat patients suffering from infectious diseases. Since then, one of these strains became the most frequently used probiotic E. coli in research and was applied to a variety of human conditions. Here, properties of that E. coli Nissle 1917 strain are compared with other commercially available E. coli probiotic strains, with emphasis on their human applications. A literature search formed the basis of a summary of research findings reported for the probiotics Mutaflor, Symbioflor 2, and Colinfant. The closest relatives of the strains in these products are presented, and their genetic content, including the presence of virulence, genes is discussed. A similarity to pathogenic strains causing urinary tract infections is noticeable. Historic trends in research of probiotics treatment for particular human conditions are identified. The future of probiotic E. coli may lay in what Alfred Nissle originally discovered: to treat gastrointestinal infections, which nowadays are often caused by antibiotic-resistant pathogens.
Enterohemorrhagic Escherichia coli (EHEC)
Scandinavian Journal of Infectious Diseases, 2005
Enterohaemorrhagic Escherichia coli has since the last 2 decades been known to cause severe and bloody diarrhoea as well as haemorrhagic colitis (HC) and haemorrhagic uraemic syndrome (HUS) especially among children. The importance of screening for EHEC among children and older patients with severe symptoms is apparent. Production of the verocytotoxins VT1 and VT2 are the main features of EHEC, and the VT types and mode of action during human infection is described. There are, however, other features adding to the pathogenicity. In this review we deal with the importance of properties such as fimbriae and adhesins as well as systems to meet the bacterial need for iron during infection. These factors are probably important for the establishment of EHEC in the gut and add to the bacterial virulence. It has now become evident that VT producing E. coli, irrespective of serogroup, might be human pathogens. We conclude that knowledge of the different possible virulence factors adds to the possibility of separating more virulent from less virulent isolates.
FEMS Immunology & Medical Microbiology, 2004
The probiotic Escherichia coli strain Nissle 1917 (Mutaflor 0 ) of serotype O6:K5:H1 was reported to protect gnotobiotic piglets from infection with Salmonella enterica serovar Typhimurium. An important virulence property of Salmonella is invasion of host epithelial cells. Therefore, we tested for interference of E. coli strain Nissle 1917 with Salmonella invasion of INT407 cells. Simultaneous administration of E. coli strain Nissle 1917 and Salmonella resulted in up to 70% reduction of Salmonella invasion efficiency. Furthermore, invasion of Yersinia enterocolitica, Shigella flexneri, Legionella pneumophila and even of Listeria monocytogenes were inhibited by the probiotic E. coli strain Nissle 1917 without affecting the viability of the invasive bacteria. The observed inhibition of invasion was not due to the production of microcins by the Nissle 1917 strain because its isogenic microcin-negative mutant SK22D was as effective as the parent strain. Reduced invasion rates were also achieved if strain Nissle 1917 was separated from the invasive bacteria as well as from the INT407 monolayer by a membrane non-permeable for bacteria. We conclude E. coli Nissle 1917 to interfere with bacterial invasion of INT407 cells via a secreted component and not relying on direct physical contact with either the invasive bacteria or the epithelial cells.
Probiotics Affect Virulence-Related Gene Expression in Escherichia coli O157:H7
Applied and Environmental Microbiology, 2007
The attachment of enterohemorrhagic Escherichia coli O157:H7 (EHEC O157) to host intestinal epithelial cells is essential for the development of hemorrhagic colitis and hemolytic-uremic syndrome in humans. Genes involved in attachment are carried within a pathogenicity island named the locus of enterocyte effacement (LEE), known to be directly activated by quorum sensing (QS). In the present study, we investigated autoinducer-2 (AI-2) production and the expression of several virulence-related genes in EHEC O157 grown in the absence and presence of a Lactobacillus acidophilus-secreted molecule(s). Transcription of important EHEC O157 virulence-related genes was studied by constructing promoter-reporter fusions and reverse transcriptase PCR. Shiga toxin (Stx) production was assayed by an enzyme immunoassay. When EHEC O157 was grown in the presence of chromatographically selected fractions of L. acidophilus La-5 cell-free spent medium, we observed a significant reduction of both extrac...