Escherichia coli O157 : H7 forms attaching and effacing lesions at the terminal rectum of cattle and colonization requires the LEE4 operon

Microbiology ◽  
2005 ◽  
Vol 151 (8) ◽  
pp. 2773-2781 ◽  
Author(s):  
Stuart W. Naylor ◽  
Andrew J. Roe ◽  
Pablo Nart ◽  
Kevin Spears ◽  
David. G. E. Smith ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Type Iii Secretion ◽  
Reservoir Host ◽  
Escherichia Coli O157 ◽  
Lesion Formation ◽  
Vaccine Candidates ◽  
E Coli ◽  
Type Iii ◽  
Transmission Electron ◽  
Associated Proteins

Enterohaemorrhagic Escherichia coli O157 : H7 is a human pathogen that causes no apparent disease in cattle, its primary reservoir host. Recent research has demonstrated that E. coli O157 : H7 predominately colonizes the distal few centimetres of the bovine rectum, and in this study, the LEE4 operon encoding a type III secretion system translocon and associated proteins was shown to be essential for colonization. A deletion mutant of LEE4 failed to colonize cattle, in contrast to a co-inoculated strain containing a chromosomal complement of the operon, therefore fulfilling ‘molecular’ Koch's postulates for this virulence determinant. In addition, attaching and effacing (A/E) lesions were detectable in E. coli O157 : H7 microcolonies from the terminal rectum of both naturally and experimentally colonized cattle when examined by transmission electron microscopy. This study proves that type III secretion is required for colonization of cattle by E. coli O157 : H7, and that A/E lesion formation occurs at the bovine terminal rectum within E. coli O157 : H7 microcolonies. The research confirms the value of using type III secreted proteins as vaccine candidates in cattle.

scholarly journals Escherichia coli type III secretion system 2 (ETT2) is widely distributed in avian pathogenic Escherichia coli isolates from Eastern China

2016 ◽  
Vol 144 (13) ◽  
pp. 2824-2830 ◽  
Author(s):  
S. WANG ◽  
X. LIU ◽  
X. XU ◽  
Y. ZHAO ◽  
D. YANG ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Type Iii Secretion ◽  
Bacterial Infections ◽  
Eastern China ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Secretion Systems ◽  
E Coli ◽  
Type Iii ◽  
System 2

SUMMARYPathogens utilize type III secretion systems to deliver effector proteins, which facilitate bacterial infections. The Escherichia coli type III secretion system 2 (ETT2) which plays a crucial role in bacterial virulence, is present in the majority of E. coli strains, although ETT2 has undergone widespread mutational attrition. We investigated the distribution and characteristics of ETT2 in avian pathogenic E. coli (APEC) isolates and identified five different ETT2 isoforms, including intact ETT2, in 57·6% (141/245) of the isolates. The ETT2 locus was present in the predominant APEC serotypes O78, O2 and O1. All of the ETT2 loci in the serotype O78 isolates were degenerate, whereas an intact ETT2 locus was mostly present in O1 and O2 serotype strains, which belong to phylogenetic groups B2 and D, respectively. Interestingly, a putative second type III secretion-associated locus (eip locus) was present only in the isolates with an intact ETT2. Moreover, ETT2 was more widely distributed in APEC isolates and exhibited more isoforms compared to ETT2 in human extraintestinal pathogenic E. coli, suggesting that APEC might be a potential risk to human health. However, there was no distinct correlation between ETT2 and other virulence factors in APEC.

scholarly journals A pH-dependent conformational change in EspA, a component of the Escherichia coli O157:H7 type III secretion system

FEBS Journal ◽  
2005 ◽  
Vol 272 (11) ◽  
pp. 2773-2783 ◽  
Author(s):  
Tomoaki Kato ◽  
Daizo Hamada ◽  
Takashi Fukui ◽  
Makoto Hayashi ◽  
Takeshi Honda ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Conformational Change ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Escherichia Coli O157 ◽  
Type Iii ◽  
Ph Dependent

scholarly journals Escherichia coli O157[ratio ]H7 infection of calves: infectious dose and direct contact transmission

2001 ◽  
Vol 127 (3) ◽  
pp. 555-560 ◽  
Author(s):  
T. E. BESSER ◽  
B. L. RICHARDS ◽  
D. H. RICE ◽  
D. D. HANCOCK
Keyword(s):  
Escherichia Coli ◽  
Direct Contact ◽  
Reservoir Host ◽  
Human Infection ◽  
Escherichia Coli O157 ◽  
Faecal Excretion ◽  
Infectious Dose ◽  
E Coli ◽  
Electrophoretic Patterns ◽  
Contact Transmission

Cattle are considered to be a reservoir host of Escherichia coli O157[ratio ]H7 and contaminated foods of bovine origin are important vehicles of human infection. In this study, the susceptibility of calves to experimental E. coli O157[ratio ]H7 infection following low oral exposures was determined. Two of 17 calves exposed to very low (<300 c.f.u.) doses, and 3 of 4 calves exposed to low (<10000 c.f.u.) doses, subsequently excreted the challenge strains in their faeces. All calves (n = 12) sharing isolation rooms with calves that excreted the challenge strain in their faeces similarly began faecal excretion of the same strains within 21 days or less. The identity between the challenge strains and the strains excreted in calf faeces was confirmed by restriction digestion electrophoretic patterns using pulsed field gel electrophoresis. Calves shed E. coli O157[ratio ]H7 in their faeces after very low dose exposures at concentrations ranging from <30 to >107 c.f.u./g, and for durations similar to the values previously reported for calves challenged by larger doses. The susceptibility of calves to infection following very low exposures or direct contact with infected calves has important implications for programmes for pre-harvest control of this agent.

scholarly journals Quorum-Sensing Escherichia coli Regulator A: a Regulator of the LysR Family Involved in the Regulation of the Locus of Enterocyte Effacement Pathogenicity Island in Enterohemorrhagic E. coli

2002 ◽  
Vol 70 (6) ◽  
pp. 3085-3093 ◽  
Author(s):  
Vanessa Sperandio ◽  
Caiyi C. Li ◽  
James B. Kaper
Keyword(s):  
Escherichia Coli ◽  
Quorum Sensing ◽  
Type Iii Secretion ◽  
Pathogenicity Island ◽  
The Other ◽  
E Coli ◽  
Type Iii ◽  
Enterocyte Effacement ◽  
K 12 ◽  
Lysr Family

ABSTRACT The locus of enterocyte effacement (LEE) is a chromosomal pathogenicity island that encodes the proteins involved in the formation of the attaching and effacing lesions by enterohemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC). The LEE comprises 41 open reading frames organized in five major operons, LEE1, LEE2, LEE3, tir (LEE5), and LEE4, which encode a type III secretion system, the intimin adhesin, the translocated intimin receptor (Tir), and other effector proteins. The first gene of LEE1 encodes the Ler regulator, which activates all the other genes within the LEE. We previously reported that the LEE genes were activated by quorum sensing through Ler (V. Sperandio, J. L. Mellies, W. Nguyen, S. Shin, and J. B. Kaper, Proc. Natl. Acad. Sci. USA 96:15196-15201, 1999). In this study we report that a putative regulator in the E. coli genome is itself activated by quorum sensing. This regulator is encoded by open reading frame b3243; belongs to the LysR family of regulators; is present in EHEC, EPEC, and E. coli K-12; and shares homology with the AphB and PtxR regulators of Vibrio cholerae and Pseudomonas aeruginosa, respectively. We confirmed the activation of b3243 by quorum sensing by using transcriptional fusions and renamed this regulator quorum-sensing E. coli regulator A (QseA). We observed that QseA activated transcription of ler and therefore of the other LEE genes. An EHEC qseA mutant had a striking reduction of type III secretion activity, which was complemented when qseA was provided in trans. Similar results were also observed with a qseA mutant of EPEC. The QseA regulator is part of the regulatory cascade that regulates EHEC and EPEC virulence genes by quorum sensing.

scholarly journals A Degenerate Type III Secretion System from Septicemic Escherichia coli Contributes to Pathogenesis

2005 ◽  
Vol 187 (23) ◽  
pp. 8164-8171 ◽  
Author(s):  
Diana Ideses ◽  
Uri Gophna ◽  
Yossi Paitan ◽  
Roy R. Chaudhuri ◽  
Mark J. Pallen ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Gene Cluster ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Gene Clusters ◽  
Secretion System ◽  
Effector Proteins ◽  
E Coli ◽  
Type Iii

ABSTRACT The type III secretion system (T3SS) is an important virulence factor used by several gram-negative bacteria to deliver effector proteins which subvert host cellular processes. Enterohemorrhagic Escherichia coli O157 has a well-defined T3SS involved in attachment and effacement (ETT1) and critical for virulence. A gene cluster potentially encoding an additional T3SS (ETT2), which resembles the SPI-1 system in Salmonella enterica, was found in its genome sequence. The ETT2 gene cluster has since been found in many E. coli strains, but its in vivo role is not known. Many of the ETT2 gene clusters carry mutations and deletions, raising the possibility that they are not functional. Here we show the existence in septicemic E. coli strains of an ETT2 gene cluster, ETT2sepsis, which, although degenerate, contributes to pathogenesis. ETT2sepsis has several premature stop codons and a large (5 kb) deletion, which is conserved in 11 E. coli strains from cases of septicemia and newborn meningitis. A null mutant constructed to remove genes coding for the putative inner membrane ring of the secretion complex exhibited significantly reduced virulence. These results are the first demonstration of the importance of ETT2 for pathogenesis.

scholarly journals Transcriptome of Enterohemorrhagic Escherichia coli O157 Adhering to Eukaryotic Plasma Membranes

2004 ◽  
Vol 72 (9) ◽  
pp. 5452-5459 ◽  
Author(s):  
Sivan Dahan ◽  
Stuart Knutton ◽  
Robert K. Shaw ◽  
Valerie F. Crepin ◽  
Gordon Dougan ◽  
...  
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Dna Microarray ◽  
Type Iii Secretion ◽  
Plasma Membranes ◽  
Enterohemorrhagic Escherichia Coli ◽  
Escherichia Coli O157 ◽  
Type Iii

ABSTRACT Using a DNA microarray, we determined changes in enterohemorrhagic Escherichia coli O157:H7 gene expression during binding to plasma membranes. Analysis of the complete transcriptomes of the bound bacteria revealed increased levels of stress-associated mRNAs and decreased levels of mRNA encoding proteins involved in translation and type III secretion.

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