scholarly journals Pathogenic Escherichia coli – virulence mechanisms

2016 ◽  
Vol 72 (6) ◽  
pp. 352-357
Author(s):  
Katarzyna Półtorak ◽  
Kinga Wieczorek ◽  
Jacek Osek
Keyword(s):  
Bloodstream Infections ◽  
Epidemiological Data ◽  
Intestinal Epithelial ◽  
Bacterial Strains ◽  
Internal Organs ◽  
E Coli ◽  
Cellular Processes ◽  
Pathogenic Escherichia Coli ◽  
Different Strains

E. coli are the predominant microorganisms in the human gastrointestinal tract. In most cases, they exist as harmless comensals, and some of them are beneficial to their host in balancing gut flora and absorption of nutrients. However, there are pathogenic strains that cause a broad range of diseases in humans and animals, from diarrhea to bloodstream infections. Among bacterial strains causing these symptoms, seven pathotypes are now recognized: enteropathogenic E. coli (EPEC), shiga toxin-producing E. coli (STEC), enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), enteroaggregative E. coli (EAEC), diffusely adherent E. coli (DAEC), and adherent-invasive E. coli (AIEC). Several different strains cause diverse diseases by means of virulence factors that facilitate their interactions with the host, including colonization of the intestinal epithelial surfaces, crossing of the mucosal barriers, invasion of the bloodstream and internal organs or producing toxins that affect various cellular processes. Pathogenic E. coli are commonly studied in humans, animals, food and the environment, in developed and developing countries. The presented paper reviews recent information concerning the pathogenic mechanisms of E. coli, the role of animals and food in the transmission chain and a short overview of epidemiological data.

scholarly journals Invasiveness of Escherichia coli Is Associated with an IncFII Plasmid

Pathogens ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1645
Author(s):  
Lars Johannes Krall ◽  
Sabrina Klein ◽  
Sébastien Boutin ◽  
Chia Ching Wu ◽  
Aline Sähr ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Bloodstream Infections ◽  
Intestinal Epithelial ◽  
Genetic Changes ◽  
E Coli ◽  
Underlying Mechanisms ◽  
Evolutionary Route ◽  
Invasion Assays

Escherichia coli is one of the most prevalent pathogens, causing a variety of infections including bloodstream infections. At the same time, it can be found as a commensal, being part of the intestinal microflora. While it is widely accepted that pathogenic strains can evolve from colonizing E. coli strains, the evolutionary route facilitating the commensal-to-pathogen transition is complex and remains not fully understood. Identification of the underlying mechanisms and genetic changes remains challenging. To investigate the factors involved in the transition from intestinal commensal to invasive E. coli causing bloodstream infections, we compared E. coli isolated from blood culture to isolates from the rectal flora of the same individuals by whole genome sequencing to identify clonally related strains and potentially relevant virulence factors. in vitro invasion assays using a Caco- 2 cell intestinal epithelial barrier model and a gut organoid model were performed to compare clonally related E. coli. The experiments revealed a correlation between the presence of an IncFII plasmid carrying hha and the degree of invasiveness. In summary, we provide evidence for the role of an IncFII plasmid in the transition of colonization to invasion in clinical E. coli isolates.

scholarly journals Molecular Characterization of Commensal Escherichia coli Adapted to Different Compartments of the Porcine Gastrointestinal Tract

2012 ◽  
Vol 78 (19) ◽  
pp. 6799-6803 ◽  
Author(s):  
Sam Abraham ◽  
David M. Gordon ◽  
James Chin ◽  
Huub J. M. Brouwers ◽  
Peter Njuguna ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Gastrointestinal Tract ◽  
Random Amplified Polymorphic Dna ◽  
Content Type ◽  
E Coli ◽  
Plasmid Replicon ◽  
Different Strains ◽  
Different Characteristics

ABSTRACTThe role ofEscherichia colias a pathogen has been the focus of considerable study, while much less is known about it as a commensal and how it adapts to and colonizes different environmental niches within the mammalian gut. In this study, we characterizeEscherichia coliorganisms (n= 146) isolated from different regions of the intestinal tracts of eight pigs (dueodenum, ileum, colon, and feces). The isolates were typed using the method of random amplified polymorphic DNA (RAPD) and screened for the presence of bacteriocin genes and plasmid replicon types. Molecular analysis of variance using the RAPD data showed thatE. coliisolates are nonrandomly distributed among different gut regions, and that gut region accounted for 25% (P< 0.001) of the observed variation among strains. Bacteriocin screening revealed that a bacteriocin gene was detected in 45% of the isolates, with 43% carrying colicin genes and 3% carrying microcin genes. Of the bacteriocins observed (H47, E3, E1, E2, E7, Ia/Ib, and B/M), the frequency with which they were detected varied with respect to gut region for the colicins E2, E7, Ia/Ib, and B/M. The plasmid replicon typing gave rise to 25 profiles from the 13 Inc types detected. Inc F types were detected most frequently, followed by Inc HI1 and N types. Of the Inc types detected, 7 were nonrandomly distributed among isolates from the different regions of the gut. The results of this study indicate that not only may the different regions of the gastrointestinal tract harbor different strains ofE. colibut also that strains from different regions have different characteristics.

scholarly journals Extraintestinal pathogenic Escherichia coli in Saudi Arabia: A review of antimicrobial resistance and molecular epidemiology

2020 ◽  
Vol 19 (2) ◽  
pp. 447-453
Author(s):  
Abdulaziz Alqasim
Keyword(s):  
Escherichia Coli ◽  
Saudi Arabia ◽  
Antimicrobial Resistance ◽  
Molecular Epidemiology ◽  
Bloodstream Infections ◽  
Epidemiological Studies ◽  
Colistin Resistance ◽  
E Coli ◽  
Extended Spectrum ◽  
Pathogenic Escherichia Coli

Extra-intestinal pathogenic Escherichia coli (ExPEC) is commonly associated with causing urinary tract and bloodstream infections. Over the past two decades, the antimicrobial resistance of ExPEC has increasingly been reported [1]. Given that Saudi Arabia annually hosts mass religious events, such as Hajj, this review investigated several aspects of antimicrobial resistance of ExPEC in this country including the current prevalence of resistance and molecular epidemiology of ExPEC isolates. Generally, the overall prevalence of antibiotic resistance of ExPEC in Saudi Arabia is on increase. The current emergence of colistin resistance in ExPEC represents a major challenge to public health. Local molecular epidemiological studies have shown the dominance of E. coli sequence type 131 (E. coli ST131) over other major ExPEC STs. This is an important observation given that this clone has been associated with high multidrug resistance and extended-spectrum β-lactamases carriage. To reduce the burden of this resistance in the future, it would be crucial to avoid uncontrolled use of antibiotics in either clinical settings or animal food industry. Keywords: Extra-intestinal pathogenic Escherichia coli, Antimicrobial resistance, ST131, Saudi Arabia, Colistin resistance, Extended-spectrum β-lactamases

scholarly journals Prophages and Past Prophage-Host Interactions Revealed by CRISPR Spacer Content in a Fish Pathogen

2020 ◽  
Vol 8 (12) ◽  
pp. 1919
Author(s):  
Elina Laanto ◽  
Janne J. Ravantti ◽  
Lotta-Riina Sundberg
Keyword(s):  
Flavobacterium Columnare ◽  
Strain Atcc ◽  
Human Pathogens ◽  
Fish Pathogen ◽  
Bacterial Strains ◽  
Host Interactions ◽  
Different Strains ◽  
Gene Orthologs ◽  
Similar Genome Organization

The role of prophages in the evolution, diversification, or virulence of the fish pathogen Flavobacterium columnare has not been studied thus far. Here, we describe a functional spontaneously inducing prophage fF4 from the F. columnare type strain ATCC 23463, which is not detectable with commonly used prophage search methods. We show that this prophage type has a global distribution and is present in strains isolated from Finland, Thailand, Japan, and North America. The virions of fF4 are myoviruses with contractile tails and infect only bacterial strains originating from Northern Finland. The fF4 resembles transposable phages by similar genome organization and several gene orthologs. Additional bioinformatic analyses reveal several species in the phylum Bacteroidetes that host a similar type of putative prophage, including bacteria that are important animal and human pathogens. Furthermore, a survey of F. columnare Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) spacers indicate a shared evolutionary history between F. columnare strains and the fF4 phage, and another putative prophage in the F. columnare strain ATCC 49512, named p49512. First, CRISPR spacer content from the two CRISPR loci (types II-C and VI-B) of the fF4 lysogen F. columnare ATCC 23463 revealed a phage terminase protein-matching spacer in the VI-B locus. This spacer is also present in two Chinese F. columnare strains. Second, CRISPR analysis revealed four F. columnare strains that contain unique spacers targeting different regions of the putative prophage p49512 in the F. columnare strain ATCC 49512, despite the geographical distance or genomovar of the different strains. This suggests a common ancestry for the F. columnare prophages and different host strains.

scholarly journals Role of Virulence Factors in Resistance of Avian Pathogenic Escherichia coli to Serum and in Pathogenicity

2003 ◽  
Vol 71 (1) ◽  
pp. 536-540 ◽  
Author(s):  
Melha Mellata ◽  
Maryvonne Dho-Moulin ◽  
Charles M. Dozois ◽  
Roy Curtiss ◽  
Peter K. Brown ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Virulence Factors ◽  
Bacterial Resistance ◽  
Serum Resistance ◽  
Temperature Sensitive ◽  
E Coli ◽  
Pathogenic Escherichia Coli ◽  
K1 Capsule

ABSTRACT In chickens, colibacillosis is caused by avian pathogenic Escherichia coli (APEC) via respiratory tract infection. Many virulence factors, including type 1 (F1A) and P (F11) fimbriae, curli, aerobactin, K1 capsule, and temperature-sensitive hemagglutinin (Tsh) and plasmid DNA regions have been associated with APEC. A strong correlation between serum resistance and virulence has been demonstrated, but roles of virulence factors in serum resistance have not been well elucidated. By using mutants of APEC strains TK3, MT78, and χ7122, which belong to serogroups O1, O2, and O78, respectively, we investigated the role of virulence factors in resistance to serum and pathogenicity in chickens. Our results showed that serum resistance is one of the pathogenicity mechanisms of APEC strains. Virulence factors that increased bacterial resistance to serum and colonization of internal organs of infected chickens were O78 lipopolysaccharide of E. coli χ7122 and the K1 capsule of E. coli MT78. In contrast, curli, type 1, and P fimbriae did not appear to contribute to serum resistance. We also showed that the iss gene, which was previously demonstrated to increase resistance to serum in certain E. coli strains, is located on plasmid pAPEC-1 of E. coli χ7122 but does not play a major role in resistance to serum for strain χ7122.

scholarly journals The controversial role of Enterococcus faecalis in colorectal cancer

2018 ◽  
Vol 11 ◽  
pp. 175628481878360 ◽  
Author(s):  
Carolina Vieira de Almeida ◽  
Antonio Taddei ◽  
Amedeo Amedei
Keyword(s):  
Colorectal Cancer ◽  
Enterococcus Faecalis ◽  
Protective Role ◽  
Published Data ◽  
Intestinal Epithelial ◽  
Bacterial Strains ◽  
Cancer Types ◽  
Probiotic Microorganism ◽  
Established Role

Colorectal cancer (CRC) is a complex and widespread disease, currently ranked as the third most frequent cancer worldwide. It is well known that the gut microbiota has an essential role in the initiation and promotion of different cancer types, particularly gastrointestinal tumors. In fact, bacteria can trigger chronic inflammation of the gastric mucosal, which can induce irreversible changes to intestinal epithelial cells, thus predisposing individuals to cancer. Some bacterial strains, such as Helicobacter pylori, Streptococcus bovis, Bacteroides fragilis, Clostridium septicum and Fusobacterium spp. have a well established role in CRC development. However, the role of Enterococcus faecalis still remains controversial. While part of the literature suggests a harmful role, other papers reported E. faecalis as an important probiotic microorganism, with great applicability in food products. In this review we have examined the vast majority of published data about E. faecalis either in CRC development or concerning its protective role. Our analysis should provide some answers regarding the controversial role of E. faecalis in CRC.

scholarly journals Transcription Regulator YgeK Affects the Virulence of Avian Pathogenic Escherichia coli

Animals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3018
Author(s):  
Jian Tu ◽  
Dandan Fu ◽  
Yi Gu ◽  
Ying Shao ◽  
Xiangjun Song ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Transcriptional Regulator ◽  
Avian Pathogenic Escherichia Coli ◽  
E Coli ◽  
Pathogenic Escherichia Coli ◽  
System 2 ◽  
Important Regulator ◽  
Alignment Analysis ◽  
Responsible Pathogen

Avian pathogenic Escherichia coli (APEC) is the responsible pathogen for colibacillosis in poultry, and is a potential gene source for human extraintestinal pathogenic Escherichia coli. Escherichia coli type III secretion system 2 (ETT2) is widely distributed in human and animal ExPEC isolates, and is crucial for the virulence of ExPEC. Transcriptional regulator YgeK, located in the ETT2 gene cluster, was identified as an important regulator of gene expression in enterohemorrhagic E. coli (EHEC). However, the role of YgeK in APEC has not been reported. In this study, we performed amino acid alignment analysis of YgeK among different E. coli strains and generated ygeK mutant strain AE81ΔygeK from clinical APEC strain AE81. Flagellar formation, bacterial motility, serum sensitivity, adhesion, and virulence were all significantly reduced following the inactivation of YgeK in APEC. Then, we performed transcriptome sequencing to analyze the functional pathways involved in the biological processes. Results suggested that ETT2 transcriptional regulator YgeK plays a crucial role in APEC virulence. These findings thus contribute to our understanding of the function of the ETT2 cluster, and clarify the pathogenic mechanism of APEC.

scholarly journals Balanced Input from the tRNA Prenyltransferase MiaA Controls the Stress Resistance and Virulence Potential of Extraintestinal Pathogenic Escherichia coli

2021 ◽  
Author(s):  
Matthew G. Blango ◽  
Brittany A. Fleming ◽  
William M. Kincannon ◽  
Alex Tran ◽  
Adam J. Lewis ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Stress Resistance ◽  
Osmotic Shock ◽  
Bloodstream Infections ◽  
E Coli ◽  
Translational Frameshifting ◽  
Virulence Potential ◽  
Pathogenic Escherichia Coli ◽  
Hostile Environments ◽  
Fine Tune

ABSTRACTAn ability to adapt to rapidly changing and often hostile environments is key to the success of many bacterial pathogens. In Escherichia coli, the highly conserved enzymes MiaA and MiaB mediate the sequential prenylation and methylthiolation of adenosine-37 within tRNAs that decode UNN codons. Here, we show that MiaA, but not MiaB, is critical to the fitness and virulence of extraintestinal pathogenic E. coli (ExPEC), a major cause of urinary tract and bloodstream infections. Deletion of miaA has pleiotropic effects, rendering ExPEC especially sensitive to stressors like nitrogen and oxygen radicals and osmotic shock. We find that stress can stimulate striking changes in miaA expression, which in turn can increase translational frameshifting and markedly alter the bacterial proteome. Cumulatively, these data indicate that ExPEC, and likely other organisms, can vary MiaA levels as a means to fine-tune translation and the spectrum of expressed proteins in response to changing environmental challenges.

scholarly journals The Type VI Secretion System of Xanthomonas phaseoli pv. manihotis is involved in virulence and in vitro motility

2020 ◽  
Author(s):  
Nathaly Andrea Montenegro Benavides ◽  
Alejandro Alvarez Borrero ◽  
Mario Luis Arrieta Ortiz ◽  
Luis Miguel Rodriguez-R. ◽  
David Octavio Botero Rozo ◽  
...  
Keyword(s):  
Gene Knockout ◽  
Phylogenetic Analyses ◽  
Gene Clusters ◽  
Secretion System ◽  
Type Vi Secretion System ◽  
Cellular Processes ◽  
Protein Secretion System ◽  
Different Strains

Abstract Background: The type VI protein secretion system (T6SS) is important in diverse cellular processes in Gram-negative bacteria, including interactions with other bacteria and with eukaryotic hosts. In this study we analyze the evolution of the T6SS in the genus Xanthomonas and evaluate its importance of the T6SS for virulence and in vitro motility in Xanthomonas phaseoli pv. manihotis (Xpm), the causal agent of bacterial blight in cassava (Manihot esculenta). We delineate the organization of the T6SS gene clusters in Xanthomonas and then characterize proteins of this secretion system in Xpm strain CIO151. Results: We describe the presence of three different clusters in the genus Xanthomonas that vary in their organization and degree of synteny between species. Using a gene knockout mutagenesis, we also found that vgrG and hcp are required for maximal aggressiveness of Xpm on cassava plants while clpV is important for both motility and maximal aggressiveness. Conclusion: We characterized the T6SS in 15 different strains in Xanthomonas and our phylogenetic analyses suggest that the T6SS might have been acquired by a very ancient event of horizontal gene transfer and maintained through evolution, hinting at their importance for the adaptation of Xanthomonas to their hosts. Finally, we demonstrated that the T6SS of Xpm is functional, and significantly contributes to virulence and motility. This is the first experimental study that demonstrates the role of the T6SS in the Xpm-cassava interaction and the T6SS organization in the genus Xanthomonas.

scholarly journals P076 Role of gut microbiota in mediating the effects of thiopurines

2020 ◽  
Vol 14 (Supplement_1) ◽  
pp. S173-S174
Author(s):  
M Franzin ◽  
M Lucafò ◽  
C Lagatolla ◽  
G Stocco ◽  
G Decorti
Keyword(s):  
Gut Microbiota ◽  
Growth Phase ◽  
Statistical Significance ◽  
Jurkat Cells ◽  
Uv Spectrophotometry ◽  
Bacterial Strains ◽  
Cytotoxic Effects ◽  
E Coli

Abstract Background A general consensus exists that patients with inflammatory bowel disease (IBD) present compositional changes in the gut microbiota (dysbiosis), including an increase in the abundance of Enterobacteriaceae. Thiopurine drugs are commonly used in the maintenance of remission in IBD. In this context, the purpose of the project is to explore the role of candidate bacterial strains in mediating the effects of thiopurines in vitro. Methods Azathioprine (AZA), mercaptopurine (MP) and thioguanine (TG) (400 µM) were incubated in minimal salts medium (M9) in presence or not of E. coli, S. enterica and K. pneumoniae and of their growth phase broths (GPB) for 4 h at 37°C. The viability of NALM6 (B cells) and JURKAT (T cells) exposed to serial dilution of drugs (ranging from 0.2 to 15 μM of AZA, from 0.3 to 20 μM of MP, from 0.08 to 5 μM of TG) previously incubated or not with bacteria and with their GPB was determined by the MTT assay. Absorbance peaks of thiopurines were analysed by UV spectrophotometry. Statistical significance was assessed by two-way ANOVA and Bonferroni’s post-test for MTT tests and by one-way ANOVA for UV spectra. Results In NALM6 cells, the cytotoxic effects of 15 μM of AZA, 2.5 μM of MP and 1.25 μM of TG decreased significantly (p &lt; 0.001) after incubation with K. pneumoniae (respectively 45 ± 2.9%; 34 ± 2.5%% and 21 ± 0.6%) and its GPB (respectively 41 ± 7.7%; 41 ± 5.1% and 27 ± 3.5%) compared with the drugs not previously exposed (respectively 76 ± 2.3%; 69 ± 1.7% and 43 ± 3.8%). In JURKAT cells, the cytotoxic effects of 15 μM of AZA, 2.5 μM of MP and 1.25 μM of TG decreased significantly (p &lt; 0.001) after incubation with K. pneumoniae (respectively 46 ± 2.8%; 38 ± 1.29% and 19 ± 3.3%) and its GPB (respectively 49 ± 9.4%; 38 ± 1.5% and 26 ± 1.5%) in comparison with the drugs not exposed (respectively 75 ± 4.0%; 50 ± 3.5% and 54 ± 4.0%). E. coli and S. enterica did not affect the cytotoxicity of the thiopurines. UV analysis evidenced a reduction of absorbance peaks of AZA (21 ± 0.05%), MP (32 ± 0.015%) and TG (30 ± 0.03%) after incubation with K. pneumoniae but not with its growth phase broth (GPB). Conclusion The activity of thiopurines decreased after incubation with both K. pneumoniae and its GPB. UV analysis suggested that the lower cytotoxicity of thiopurines exposed to the bacterial strain is due to the reduction of the concentration of the drugs exposed to K. pneumoniae. Moreover, the reduction of drug availability after the exposure to GPB could be explained with a possible interaction between thiopurines and capsular polysaccharides released by the bacteria.

Sign in / Sign up

Export Citation Format

Share Document