Two case reports of local envenoming by the Spotted grass snake, Psammophylax rhombeatus (Linnæus, 1758) (Serpentes, Psammophiidae).

Two cases of bites by a South African psammophiid snake, Psammophylax rhombeatus, are described and analyzed. These are the first detailed reports of local envenoming by a Psammophylax spp. While handling a wild-collected 1 m P.

Local envenoming by the Schokari sand racer, Psammophis schokari Forskål, 1775 (Serpentes, Psammophiidae) and a brief review of reported bites by sand racers (Psammophis spp.).

A recent case of a bite by a psammophiid snake, Psammophis schokari, is described and analyzed. This is the first report of local envenoming by this species. The 1 m long P.

Dissecting the role of the Tir:Nck and Tir:IRTKS/IRSp53 signalling pathways in vivo.

Attaching and effacing (A/E) lesions and actin polymerization, the hallmark of enteropathogenic Escherichia coli (EPEC), enterohemorrhagic E. coli (EHEC) and Citrobacter rodentium (CR) infections, are dependent on the effector Tir. Phosphorylation of Tir(EPEC/CR) Y474/1 leads to recruitment of Nck and neural Wiskott-Aldrich syndrome protein (N-WASP) and strong actin polymerization in cultured cells.

Interactions of typical and atypical enteropathogenic Escherichia coli strains with the calf intestinal mucosa ex vivo.

Enteropathogenic Escherichia coli (EPEC) can be found in healthy and diarrheic cattle; however, little is known about the role of attaching and effacing (A/E) lesion formation in colonization of bovine intestinal mucosa by such strains. We show that typical and atypical EPEC induce A/E lesions on calf intestinal explants independently of Tir tyrosine phosphorylation and TccP. Our data support the existence of conserved Tir- and TccP-independent mechanisms of A/E lesion formation in a range of hosts and reinforce the zoonotic potential of EPEC in cattle.

Modelling of infection by enteropathogenic Escherichia coli strains in lineages 2 and 4 ex vivo and in vivo by using Citrobacter rodentium expressing TccP.

Enteropathogenic Escherichia coli (EPEC) strains colonize the human gut mucosa via attaching-and-effacing (A/E) lesion formation, while in vitro they employ diverse strategies to trigger actin polymerization. Strains belonging to the EPEC-1 lineage trigger strong actin polymerization via tyrosine phosphorylation of the type III secretion system (T3SS) effector Tir, recruitment of Nck, and activation of N-WASP. Strains belonging to EPEC-2 and EPEC-4 can trigger strong actin polymerization by dual mechanisms, since while employing the Tir-Nck pathway they can additionally activate N-WASP via the T3SS effectors TccP2 and TccP, respectively.

Role of NleH, a type III secreted effector from attaching and effacing pathogens, in colonization of the bovine, ovine, and murine gut.

The human pathogen enterohemorrhagic Escherichia coli (EHEC) O157:H7 colonizes human and animal gut via formation of attaching and effacing lesions. EHEC strains use a type III secretion system to translocate a battery of effector proteins into the mammalian host cell, which subvert diverse signal transduction pathways implicated in actin dynamics, phagocytosis, and innate immunity. The genomes of sequenced EHEC O157:H7 strains contain two copies of the effector protein gene nleH, which share 49% sequence similarity with the gene for the Shigella effector OspG, recently implicated in inhibition of migration of the transcriptional regulator NF-kappaB to the nucleus.

The p50 subunit of NF-kappaB is critical for in vivo clearance of the noninvasive enteric pathogen Citrobacter rodentium.

Citrobacter rodentium, a natural mouse pathogen, belongs to the family of extracellular enteric pathogens that includes enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC). C.

Interaction of enterohemorrhagic Escherichia coli O157:H7 with mouse intestinal mucosa.

In this study, we used mouse ileal loops to investigate the interaction of enterohemorrhagic Escherichia coli (EHEC) O157:H7 with the mouse intestinal mucosa. With a dose of 10(9) and 3 h incubation, EHEC O157 was detected in the lumen and to a lesser extent associated with the epithelium. Typical attaching and effacing (A/E) lesions were seen, albeit infrequently.

Functional studies of intimin in vivo and ex vivo: implications for host specificity and tissue tropism.

Intimin is an outer-membrane adhesin that is essential for colonization of the host gastrointestinal tract by attaching and effacing pathogens including enteropathogenic Escherichia coli (EPEC), enterohaemorrhagic E. coli (EHEC) and Citrobacter rodentium (CR). The N-terminus of intimin from the different strains is highly conserved while the C-terminus, which harnesses the active receptor-binding site, shows sequence and antigenic polymorphism.

Adherence of enterohemorrhagic Escherichia coli O157, O26, and O111 strains to bovine intestinal explants ex vivo.

We used bovine intestinal organ culture to study infection by enterohemorrhagic Escherichia coli serogroups O157, O26, and O111. We show colonization and attaching and effacing lesion formation on explants derived from the ileum, colon, and rectum. Intimin and Tir were detected at the sites of adherent bacteria; Tir was essential for colonization.

Comparison of colonization dynamics and pathology of mice infected with enteropathogenic Escherichia coli, enterohaemorrhagic E. coli and Citrobacter rodentium.

Enteropathogenic Escherichia coli (EPEC), enterohaemorrhagic E. coli (EHEC) and Citrobacter rodentium (CR) colonize the gastrointestinal tract epithelium via attaching and effacing lesions. While humans are believed to be the only living reservoir of typical EPEC and EHEC to have border host specificity, CR is a restricted mouse pathogen.

Use of virulence factor-specific egg yolk-derived immunoglobulins as a promising alternative to antibiotics for prevention of attaching and effacing Escherichia coli infections.

Using a porcine ileal in vitro organ culture model, we have demonstrated that egg yolk-derived antibodies specific for the attaching and effacing Escherichia coli (AEEC) virulence factors intimin and translocated intimin receptor (Tir), but not those specific for the AEEC-secreted proteins EspA, EspB and EspD, significantly reduced the bacterial adherence of the porcine enteropathogenic E. coli strain ECL1001, formerly 86-1390. Moreover, antibodies specific for intimin and Tir also significantly reduced bacterial adherence of heterologous AEEC strains, including human, bovine and canine enteropathogenic E.

Interaction of enteropathogenic and Shiga toxin-producing Escherichia coli and porcine intestinal mucosa: role of intimin and Tir in adherence.

The ileal in vitro organ culture (IVOC) model using tissues originating from colostrum-deprived newborn piglets has proven to be an effective way to study the attaching and effacing (A/E) phenotype of porcine enteropathogenic Escherichia coli (EPEC) ex vivo. The aim of this study was to investigate the role of intimin subtype and Tir in the adherence of EPEC and Shiga-toxin-producing E. coli (STEC), isolated from different animal species, to porcine intestinal IVOC.

Host immune status influences the development of attaching and effacing lesions in weaned pigs.

Attaching and effacing Escherichia coli (AEEC) has been associated with naturally occurring attaching and effacing (A/E) lesions in weaned pigs, and although A/E lesions have been experimentally reproduced in newborn piglets, such lesions have been much more difficult to induce in older conventional pigs. Hence, the aim of this study was to examine the effect of oral administration of dexamethasone on the development of A/E lesions in weaned pigs challenged with a porcine enteropathogenic E. coli (PEPEC) strain and to investigate the involvement of local intestinal cytokine response.

Characterization of the novel factor paa involved in the early steps of the adhesion mechanism of attaching and effacing Escherichia coli.

Nonenterotoxigenic porcine Escherichia coli strains belonging to the serogroup O45 have been associated with postweaning diarrhea in swine and adhere to intestinal epithelial cells in a characteristic attaching and effacing (A/E) pattern. O45 porcine enteropathogenic E. coli (PEPEC) strain 86-1390 induces typical A/E lesions in a pig ileal explant model.