scholarly journals Escherichia coli Shiga Toxins and Gut Microbiota Interactions

Toxins ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 416
Author(s):  
Kyung-Soo Lee ◽  
Yu-Jin Jeong ◽  
Moo-Seung Lee
Keyword(s):  
Escherichia Coli ◽  
Bacterial Communities ◽  
Pathogenic Bacteria ◽  
Bacterial Species ◽  
Shigella Dysenteriae ◽  
Host Cells ◽  
Severe Illness ◽  
Shiga Toxins ◽  
Serotype 1 ◽  
Lethal Complications

Escherichia coli (EHEC) and Shigella dysenteriae serotype 1 are enterohemorrhagic bacteria that induce hemorrhagic colitis. This, in turn, may result in potentially lethal complications, such as hemolytic uremic syndrome (HUS), which is characterized by thrombocytopenia, acute renal failure, and neurological abnormalities. Both species of bacteria produce Shiga toxins (Stxs), a phage-encoded exotoxin inhibiting protein synthesis in host cells that are primarily responsible for bacterial virulence. Although most studies have focused on the pathogenic roles of Stxs as harmful substances capable of inducing cell death and as proinflammatory factors that sensitize the host target organs to damage, less is known about the interface between the commensalism of bacterial communities and the pathogenicity of the toxins. The gut contains more species of bacteria than any other organ, providing pathogenic bacteria that colonize the gut with a greater number of opportunities to encounter other bacterial species. Notably, the presence in the intestines of pathogenic EHEC producing Stxs associated with severe illness may have compounding effects on the diversity of the indigenous bacteria and bacterial communities in the gut. The present review focuses on studies describing the roles of Stxs in the complex interactions between pathogenic Shiga toxin-producing E. coli, the resident microbiome, and host tissues. The determination of these interactions may provide insights into the unresolved issues regarding these pathogens.

scholarly journals Stx-Producing Shigella Species From Patients in Haiti: An Emerging Pathogen With the Potential for Global Spread

2015 ◽  
Vol 2 (4) ◽  
Author(s):  
Miranda D. Gray ◽  
Susan R. Leonard ◽  
David W. Lacher ◽  
Keith A. Lampel ◽  
Meer T. Alam ◽  
...  
Keyword(s):  
United States ◽  
Escherichia Coli ◽  
The United States ◽  
Shigella Dysenteriae ◽  
Emerging Pathogen ◽  
Shiga Toxins ◽  
Shigella Species ◽  
Global Spread ◽  
Serotype 1 ◽  
Epidemiological Link

Abstract Shiga toxins (Stx) are commonly produced by Shigella dysenteriae serotype 1 and Stx-producing Escherichia coli. However, the toxin genes have been detected in additional Shigella species. We recently reported the emergence of Stx-producing Shigella in travelers in the United States and France who had recently visited Hispaniola (Haiti and the Dominican Republic). In this study, we confirm this epidemiological link by identifying Stx-producing Shigella from Haitian patients attending clinics near Port-au-Prince. We also demonstrate that the bacteriophage encoding Stx is capable of dissemination to stx-negative Shigella species found in Haiti, suggesting that Stx-producing Shigella may become more widespread within that region.

scholarly journals hfqPlays Important Roles in Virulence and Stress Adaptation in Cronobacter sakazakii ATCC 29544

2015 ◽  
Vol 83 (5) ◽  
pp. 2089-2098 ◽  
Author(s):  
Seongok Kim ◽  
Hyelyeon Hwang ◽  
Kwang-Pyo Kim ◽  
Hyunjin Yoon ◽  
Dong-Hyun Kang ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Bacterial Species ◽  
Soft Agar ◽  
Host Cells ◽  
Neonatal Meningitis ◽  
Animal Cells ◽  
Content Type ◽  
Flagellar Biosynthesis

Cronobacterspp. are opportunistic pathogens that cause neonatal meningitis and sepsis with high mortality in neonates. Despite the peril associated withCronobacterinfection, the mechanisms of pathogenesis are still being unraveled. Hfq, which is known as an RNA chaperone, participates in the interaction with bacterial small RNAs (sRNAs) to regulate posttranscriptionally the expression of various genes. Recent studies have demonstrated that Hfq contributes to the pathogenesis of numerous species of bacteria, and its roles are varied between bacterial species. Here, we tried to elucidate the role of Hfq inC. sakazakiivirulence. In the absence ofhfq,C. sakazakiiwas highly attenuated in disseminationin vivo, showed defects in invasion (3-fold) into animal cells and survival (103-fold) within host cells, and exhibited low resistance to hydrogen peroxide (102-fold). Remarkably, the loss ofhfqled to hypermotility on soft agar, which is contrary to what has been observed in other pathogenic bacteria. The hyperflagellated bacteria were likely to be attributable to the increased transcription of genes associated with flagellar biosynthesis in a strain lackinghfq. Together, these data strongly suggest thathfqplays important roles in the virulence ofC. sakazakiiby participating in the regulation of multiple genes.

scholarly journals Identification and antibiogram study of bacterial species isolated from milk samples of different locations in Bangladesh

2016 ◽  
Vol 1 (3) ◽  
pp. 457-462 ◽  
Author(s):  
Md Nuruzzaman Munsi ◽  
Nathu Ram Sarker ◽  
Razia Khatun ◽  
Mohammed Khorshed Alam
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pathogenic Bacteria ◽  
Bacterial Species ◽  
Salmonella Typhi ◽  
Diffusion Method ◽  
Biochemical Tests ◽  
Public Health Importance ◽  
Milk Samples ◽  
First Choice

Cow’s milk containing pathogenic bacteria is an important threat to the consumers. The objectives of the present study were to identify the bacterial agents of public health importance in milk samples (n=35) of different locations and to determine their sensitivity to different antibiotics. The milk samples were collected and transported aseptically and subsequently allowed for culture in bacteriological media, Gram’s staining and biochemical tests for the identification of bacterial species. The bacteria identified were Staphylococcus aureus, Escherichia coli and Salmonella typhi, and their prevalence, in case of vendor milk specimens (n=28), were 96.43%, 53.57% and 35.71% respectively, and of brand milk specimens (n=7), were 42.86 %, 28.57% and 0%, respectively. This suggests that cautionary measures should be taken for quality milk production and consumption. The antibiotic sensitivity test was done by disc diffusion method and the average inhibition zones, in case of Staphylococcus aureus, were 32 mm for oxytetracycline, 26 mm for amoxicillin, 35 mm for ciprofloxacin, 27 mm for cefotaxime, 30 mm for ceftriaxone, 30 mm for azithromycin, and 26 mm for erythromycin; in case of Escherichia coli, were 5 mm for oxytetracycline, 9 mm for amoxicillin, 22 mm for ciprofloxacin, 30 mm for cefotaxime, 31 mm for ceftriaxone, 15 mm for azithromycin, and 0 mm for erythromycin; in case of Salmonella typhi., were 25 mm for oxytetracycline, 24 mm for amoxicillin, 38 mm for ciprofloxacin, 31 mm for cefotaxime, 34 mm for ceftriaxone, 24 mm for azithromycin, and 0 mm for erythromycin. Therefore, ciprofloxacin and ceftriaxone may be the antibiotics of first choice, and cefotaxime and azithromycin may be the second choice among the test antibiotics for the treatment of illness caused by these bacteria.Asian J. Med. Biol. Res. December 2015, 1(3): 457-462

scholarly journals Evaluation of Pathogenic Bacteria Associated with Fresh Produce obtained from Selected Markets in Abeokuta

2013 ◽  
Vol 4 (1) ◽  
pp. 75-81
Author(s):  
OR Afolabi ◽  
AR Oloyede ◽  
TA Ibrahim
Keyword(s):  
Escherichia Coli ◽  
Pathogenic Bacteria ◽  
Fresh Produce ◽  
Enterobacter Aerogenes ◽  
Total Coliform ◽  
Shigella Dysenteriae ◽  
Human Consumption ◽  
Salmonella Spp ◽  
Fresh Vegetables ◽  
Plate Counts

The bacterial quality of eight types of fresh produce obtained from selected markets in Abeokuta was determined. Two hundred forty (240) samples of fresh vegetables were examined for aerobic plate counts, coliform counts, and presence of Escherichia coli, toxigenic Staphylococcusaureus, Salmonella spp and Listeria spp. The aerobic plate counts ranged from 2.80 log10 cfu/g to 15.60 log10 cfu/g with the inner parts of cut- water melons having the highest value. Total coliform counts ranged from 0.0 to 11.80 log10 cfu/g. Pathogenic bacteria isolated were Escherichia coli,Staphylococcus aureus, Salmonella spp, Listeria spp, Shigella dysenteriae, Klebsiella pneumoniae, Enterobacter aerogenes, Bacillus spp, Pseudomonas aeruginosa and Streptococcus spp. These pathogens were mostly found at the outer leaves/ parts of the vegetables and render unsafe for human consumption. This study shows that the outer parts/ leaves of fresh produce are heavily contaminated with pathogenic bacteria and the fresh produce should be pre- treated thoroughly, so as to reduce the risk of food- borne outbreaks.Keywords · Pathogenic bacteria · Bacterial quality · Coliform counts

scholarly journals Shiga Toxins as Antitumor Tools

Toxins ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 690
Author(s):  
Aude Robert ◽  
Joëlle Wiels
Keyword(s):  
Cellular Level ◽  
Shigella Dysenteriae ◽  
Host Cells ◽  
Health Concern ◽  
28S Rrna ◽  
Shiga Toxins ◽  
Unfolded Protein ◽  
Efficient Delivery ◽  
Uremic Syndrome ◽  
Protein Response

Shiga toxins (Stxs), also known as Shiga-like toxins (SLT) or verotoxins (VT), constitute a family of structurally and functionally related cytotoxic proteins produced by the enteric pathogens Shigella dysenteriae type 1 and Stx-producing Escherichia coli (STEC). Infection with these bacteria causes bloody diarrhea and other pathological manifestations that can lead to HUS (hemolytic and uremic syndrome). At the cellular level, Stxs bind to the cellular receptor Gb3 and inhibit protein synthesis by removing an adenine from the 28S rRNA. This triggers multiple cellular signaling pathways, including the ribotoxic stress response (RSR), unfolded protein response (UPR), autophagy and apoptosis. Stxs cause several pathologies of major public health concern, but their specific targeting of host cells and efficient delivery to the cytosol could potentially be exploited for biomedical purposes. Moreover, high levels of expression have been reported for the Stxs receptor, Gb3/CD77, in Burkitt’s lymphoma (BL) cells and on various types of solid tumors. These properties have led to many attempts to develop Stxs as tools for biomedical applications, such as cancer treatment or imaging, and several engineered Stxs are currently being tested. We provide here an overview of these studies.

scholarly journals Identification of Human-Pathogenic Strains of Shiga Toxin-Producing Escherichia coli from Food by a Combination of Serotyping and Molecular Typing of Shiga Toxin Genes

2007 ◽  
Vol 73 (15) ◽  
pp. 4769-4775 ◽  
Author(s):  
Lothar Beutin ◽  
Angelika Miko ◽  
Gladys Krause ◽  
Karin Pries ◽  
Sabine Haby ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Severe Illness ◽  
Shiga Toxins ◽  
E Coli ◽  
Food Borne ◽  
Length Polymorphisms ◽  
Beef Products ◽  
Pcr Products ◽  
Shiga Toxin Genes

ABSTRACT We examined 219 Shiga toxin-producing Escherichia coli (STEC) strains from meat, milk, and cheese samples collected in Germany between 2005 and 2006. All strains were investigated for their serotypes and for genetic variants of Shiga toxins 1 and 2 (Stx1 and Stx2). stx 1 or variant genes were detected in 88 (40.2%) strains and stx 2 and variants in 177 (80.8%) strains. Typing of stx genes was performed by stx-specific PCRs and by analysis of restriction fragment length polymorphisms (RFLP) of PCR products. Major genotypes of the Stx1 (stx 1, stx 1c, and stx 1d) and the Stx2 (stx 2, stx 2d, stx 2-O118, stx 2e, and stx 2g) families were detected, and multiple types of stx genes coexisted frequently in STEC strains. Only 1.8% of the STEC strains from food belonged to the classical enterohemorrhagic E. coli (EHEC) types O26:H11, O103:H2, and O157:H7, and only 5.0% of the STEC strains from food were positive for the eae gene, which is a virulence trait of classical EHEC. In contrast, 95 (43.4%) of the food-borne STEC strains carried stx 2 and/or mucus-activatable stx 2d genes, an indicator for potential high virulence of STEC for humans. Most of these strains belonged to serotypes associated with severe illness in humans, such as O22:H8, O91:H21, O113:H21, O174:H2, and O174:H21. stx 2 and stx 2d STEC strains were found frequently in milk and beef products. Other stx types were associated more frequently with pork (stx 2e), lamb, and wildlife meat (stx 1c). The combination of serotyping and stx genotyping was found useful for identification and for assignment of food-borne STEC to groups with potential lower and higher levels of virulence for humans.

scholarly journals Comparative Structure-Function Analysis of Mannose-Specific FimH Adhesins from Klebsiella pneumoniae and Escherichia coli

2009 ◽  
Vol 191 (21) ◽  
pp. 6592-6601 ◽  
Author(s):  
Steen G. Stahlhut ◽  
Veronika Tchesnokova ◽  
Carsten Struve ◽  
Scott J. Weissman ◽  
Sujay Chattopadhyay ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Function Analysis ◽  
Bacterial Species ◽  
Host Cells ◽  
Structural Basis ◽  
Adaptive Mutation ◽  
Single Mutation ◽  
Dependent Manner ◽  
E Coli

ABSTRACT FimH, the adhesive subunit of type 1 fimbriae expressed by many enterobacteria, mediates mannose-sensitive binding to target host cells. At the same time, fine receptor-structural specificities of FimH from different species can be substantially different, affecting bacterial tissue tropism and, as a result, the role of the particular fimbriae in pathogenesis. In this study, we compared functional properties of the FimH proteins from Escherichia coli and Klebsiella pneumoniae, which are both 279 amino acids in length but differ by some ∼15% of residues. We show that K. pneumoniae FimH is unable to mediate adhesion in a monomannose-specific manner via terminally exposed Manα(1-2) residues in N-linked oligosaccharides, which are the structural basis of the tropism of E. coli FimH for uroepithelial cells. However, K. pneumoniae FimH can bind to the terminally exposed Manα(1-3)Manβ(1-4)GlcNAcβ1 trisaccharide, though only in a shear-dependent manner, wherein the binding is marginal at low shear force but enhanced sevenfold under increased shear. A single mutation in the K. pneumoniae FimH, S62A, converts the mode of binding from shear dependent to shear independent. This mutation has occurred naturally in the course of endemic circulation of a nosocomial uropathogenic clone and is identical to a pathogenicity-adaptive mutation found in highly virulent uropathogenic strains of E. coli, in which it also eliminates the dependence of E. coli binding on shear. The shear-dependent binding properties of the K. pneumoniae and E. coli FimH proteins are mediated via an allosteric catch bond mechanism. Thus, despite differences in FimH structure and fine receptor specificity, the shear-dependent nature of FimH-mediated adhesion is highly conserved between bacterial species, supporting its remarkable physiological significance.

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