scholarly journals Genomic Comparison of Two O111:H−Enterohemorrhagic Escherichia coli Isolates from a Historic Hemolytic-Uremic Syndrome Outbreak in Australia

2016 ◽  
Vol 84 (3) ◽  
pp. 775-781 ◽  
Author(s):  
Lauren J. McAllister ◽  
Stephen J. Bent ◽  
Nicola K. Petty ◽  
Elizabeth Skippington ◽  
Scott A. Beatson ◽  
...  

EnterohemorrhagicEscherichia coli(EHEC) is an important cause of diarrhea and hemolytic-uremic syndrome (HUS) worldwide. Australia's worst outbreak of HUS occurred in Adelaide in 1995 and was one of the first major HUS outbreaks attributed to a non-O157 Shiga-toxigenicE. coli(STEC) strain. Molecular analyses conducted at the time suggested that the outbreak was caused by an O111:H−clone, with strains from later in the outbreak harboring an extra copy of the genes encoding the potent Shiga toxin 2 (Stx2). Two decades later, we have used next-generation sequencing to compare two isolates from early and late in this important outbreak. We analyzed genetic content, single-nucleotide polymorphisms (SNPs), and prophage insertion sites; for the latter, we demonstrate how paired-end sequence data can be leveraged to identify such insertion sites. The two strains are genetically identical except for six SNP differences and the presence of not one but two additional Stx2-converting prophages in the later isolate. Isolates from later in the outbreak were associated with higher levels of morbidity, suggesting that the presence of the additional Stx2-converting prophages is significant in terms of the virulence of this clone.

2020 ◽  
Author(s):  
Clara Berdasco ◽  
Alipio Pinto ◽  
Mariano Blake ◽  
Fernando Correa ◽  
Nadia A. Longo Carbajosa ◽  
...  

AbstractShiga toxin 2 (Stx2) from enterohemorrhagic Escherichia coli (EHEC) produces hemorrhagic colitis, hemolytic uremic syndrome (HUS) and acute encephalopathy. The mortality rate in HUS increases significantly when the central nervous system (CNS) is involved. Besides, EHEC also releases lipopolysaccharide (LPS). Many reports have described cognitive dysfunctions in HUS patients, the hippocampus being one of the brain areas targeted by EHEC infection. In this context, a translational murine model of encephalopathy was employed to establish the deleterious effects of Stx2 and the contribution of LPS in the hippocampus. Results demonstrate that systemic administration of a sublethal dose of Stx2 reduced memory index and produced depression like behavior, pro-inflammatory cytokine release and NF-kB activation independent of the ERK 1/2 signaling pathway. On the other hand, LPS activated NF-kB dependent on ERK 1/2 signaling pathway. Cotreatment of Stx2 with LPS aggravated the pathologic state, while dexamethasone treatment succeeded in preventing behavioral alterations. Our present work suggests that the use of drugs such as corticosteroids or NF-kB signaling inhibitors may serve as neuroprotectors from EHEC infection.Author SummaryShiga toxin (Stx) from enterohemorrhagic Escherichia coli (EHEC) is one of the most virulent factors responsible for hemolytic uremic syndrome (HUS). Stx2, the endemic variant targets the brain, among other organs, thus inducing encephalopathies. Central nervous system (CNS) compromise was the main predictor of death in patients with HUS. Stx2 may exert a direct action in the CNS, by disrupting the neurovascular unit. In this context, we investigate the molecular signaling triggered by Stx2 in the murine brain hippocampus involved in inflammatory mechanisms that altered hippocampal-related cognitive behaviors. The present data underscore that the use of drugs such as dexamethasone or those blocking the cascade by preventing NF-kB translocation to the nucleus may serve as effective neuroprotectors with potentially beneficial use in the clinic.


2017 ◽  
Vol 5 (38) ◽  
Author(s):  
Anthony M. Smith ◽  
Kalule J. Bosco ◽  
Mark P. Nicol ◽  
Jackie Kleynhans ◽  
Mignon McCulloch ◽  
...  

ABSTRACT Shiga toxin-producing Escherichia coli (STEC) strains are primarily foodborne pathogens that may cause diarrheal outbreaks and are associated with severe complications, specifically hemolytic-uremic syndrome (HUS). We report here genome sequence data for STEC O26:H11, which is associated with a cluster of cases of HUS, a rarely described syndrome in South Africa.


1992 ◽  
Vol 30 (8) ◽  
pp. 2153-2157 ◽  
Author(s):  
A Cordovéz ◽  
V Prado ◽  
L Maggi ◽  
J Cordero ◽  
J Martinez ◽  
...  

PLoS ONE ◽  
2013 ◽  
Vol 8 (9) ◽  
pp. e73927 ◽  
Author(s):  
Monika Marejková ◽  
Květa Bláhová ◽  
Jan Janda ◽  
Angelika Fruth ◽  
Petr Petráš

Cytokine ◽  
2012 ◽  
Vol 60 (3) ◽  
pp. 694-700 ◽  
Author(s):  
Masaki Shimizu ◽  
Mondo Kuroda ◽  
Natsumi Sakashita ◽  
Michio Konishi ◽  
Hisashi Kaneda ◽  
...  

2020 ◽  
Vol 64 (4) ◽  
Author(s):  
Sabrina Mühlen ◽  
Isabell Ramming ◽  
Marina C. Pils ◽  
Martin Koeppel ◽  
Jana Glaser ◽  
...  

ABSTRACT Infections with enterohemorrhagic Escherichia coli (EHEC) cause disease ranging from mild diarrhea to hemolytic-uremic syndrome (HUS) and are the most common cause of renal failure in children in high-income countries. The severity of the disease derives from the release of Shiga toxins (Stx). The use of antibiotics to treat EHEC infections is generally avoided, as it can result in increased stx expression. Here, we systematically tested different classes of antibiotics and found that their influence on stx expression and release varies significantly. We assessed a selection of these antibiotics in vivo using the Citrobacter rodentium ϕstx2dact mouse model and show that stx2d-inducing antibiotics resulted in weight loss and kidney damage despite clearance of the infection. However, several non-Stx-inducing antibiotics cleared bacterial infection without causing Stx-mediated pathology. Our results suggest that these antibiotics might be useful in the treatment of EHEC-infected human patients and decrease the risk of HUS development.


2014 ◽  
Vol 1 (2) ◽  
Author(s):  
Sunao Iyoda ◽  
Shannon D. Manning ◽  
Kazuko Seto ◽  
Keiko Kimata ◽  
Junko Isobe ◽  
...  

Abstract Background.  Enterohemorrhagic Escherichia coli (EHEC) O157:H7 infection causes severe diseases such as bloody diarrhea and hemolytic uremic syndrome (HUS). Although EHEC O157:H7 strains have exhibited high genetic variability, their abilities to cause human diseases have not been fully examined. Methods.  Clade typing and stx subtyping of EHEC O157:H7 strains, which were isolated in Japan during 1999–2011 from 269 HUS patients and 387 asymptomatic carriers (ACs) and showed distinct pulsed-field gel electrophoresis patterns, were performed to determine relationships between specific lineages and clinical presentation. Results.  Clades 6 and 8 strains were more frequently found among the isolates from HUS cases than those from ACs (P = .00062 for clade 6, P < .0001 for clade 8). All clade 6 strains isolated from HUS patients harbored stx2a and/or stx2c, whereas all clade 8 strains harbored either stx2a or stx2a/stx2c. However, clade 7 strains were predominantly found among the AC isolates but less frequently found among the HUS isolates, suggesting a significant association between clade 7 and AC (P < .0001). Logistic regression analysis revealed that 0–9 year old age is a significant predictor of the association between clade 8 and HUS. We also found an intact norV gene, which encodes for a nitric oxide reductase that inhibits Shiga toxin activity under anaerobic condition, in all clades 1–3 isolates but not in clades 4–8 isolates. Conclusions.  Early detection of EHEC O157:H7 strains that belonged to clades 6/8 and harbored specific stx subtypes may be important for defining the risk of disease progression in EHEC-infected 0- to 9-year-old children.


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