Escherichia coli O157:H7 causes bloody diarrhea and potentially fatal systemic sequelae in humans. Cattle are most frequently identified as the primary source of infection, E. generally colonizes gastrointestinal tracts cattle without causing disease. In this study, persistence tropism were assessed for four different strains. Experimentally infected calves shed organism at least 14 days prior to necropsy. For majority these animals, well a naturally colonized animal obtained from commercial...

Identification of the relative importance within- and between-host variability in infectiousness impact these heterogeneities on transmission dynamics infectious agents can enable efficient targeting control measures. Cattle, a major reservoir host for zoonotic pathogen Escherichia coli O157, are known to exhibit high degree heterogeneity bacterial shedding densities. By relating count fitting dynamic epidemiological models prevalence data from cross-sectional survey cattle farms Scotland,...

ABSTRACT Escherichia coli O157:H7 is an important cause of diarrhea, hemorrhagic colitis, and potentially fatal human illness. Cattle are considered a primary reservoir infection, recent experimental evidence has indicated that the terminal rectum principal site bacterial carriage. To test this finding in naturally colonized animals, intact samples from 267 cattle 24 separate lots were obtained immediately after slaughter, fecal material mucosal surfaces cultured for E. O157 by direct...

The authors performed a retrospective study to determine the incidences and range of spontaneous pathology findings in control cynomolgus monkeys. Data were collected from 570 monkeys (285 animals per sex), aged twelve thirty-six months, sixty regulatory studies evaluated at our laboratory between 2003 2009. most common finding overall was lymphoplasmacytic infiltrates observed following incidence: liver (60.7%), kidneys (28.8%), heart (25.8%), salivary glands (21.2%), stomach (12.1%)....

Enterohaemorrhagic Escherichia coli O157 : H7 is a human pathogen that causes no apparent disease in cattle, its primary reservoir host. Recent research has demonstrated E. predominately colonizes the distal few centimetres of bovine rectum, and this study, LEE4 operon encoding type III secretion system translocon associated proteins was shown to be essential for colonization. A deletion mutant failed colonize contrast co-inoculated strain containing chromosomal complement operon, therefore...

ABSTRACT Escherichia coli O157:H7 is an important pathogen of humans. Cattle are most frequently identified as the primary source infection, and therefore, reduction in E. prevalence cattle by vaccination represents attractive strategy for reducing incidence human disease. H7 flagella have been implicated intestinal-epithelial colonization may represent a useful target vaccination. In this study, calves were immunized either systemically with flagellin intramuscular injection or mucosally...

Thyroid tissue is sensitive to the effects of endocrine disrupting substances, and this represents a significant health concern. Histopathological analysis sections rat thyroid gland remains gold standard for evaluation agrochemical on thyroid. However, there high degree variability in appearance gland, toxicologic pathologists often struggle decide consistently apply threshold recording low-grade follicular hypertrophy. This research project developed deep learning image solution that...

ABSTRACT Type III secretion systems of enteric bacteria enable translocation effector proteins into host cells. Secreted verotoxigenic Escherichia coli O157 strains include components a apparatus, EspA, -B, and -D, as well “effectors” such the translocated intimin receptor (Tir) mitochondrion-associated protein (Map). This research has investigated regulation LEE4 translocon proteins, in particular EspA. EspA filaments could not be detected on bacterial cell surface when E. O157:H7 was...

ABSTRACT Recent transposon mutagenesis studies with two enterohemorrhagic Escherichia coli (EHEC) strains, a sero- type O26:H- strain and serotype O157:H7 strain, led to identification of putative fimbrial operon that promotes colonization young calves (1 2 weeks old). The distribution the gene encoding major subunit present in O-island 61 EHEC characterized set 78 diarrheagenic E. strains was determined, this found 87.2% is therefore not an EHEC-specific region. cluster amplified by...

ABSTRACT Recent research has established that the terminal rectum is predominant colonization site of enterohemorrhagic Escherichia coli O157:H7 in cattle. The main aim present work was to investigate pathological changes and associated immune responses at this animals colonized with E. O157:H7. Tissue gastrointestinal samples from a total 22 weaned Holstein-cross calves challenged were analyzed for bacterial pathology. Five unexposed age-matched used as comparative negative controls....

ABSTRACT Non-sorbitol-fermenting (NSF) Escherichia coli O157:H7 is the primary Shiga toxin-producing E. (STEC) serotype associated with human infection. Since 1988, sorbitol-fermenting (SF) STEC O157:NM strains have emerged and been a higher incidence of progression to hemolytic-uremic syndrome (HUS) than NSF O157:H7. This study investigated bacterial factors that may account for increased pathogenic potential SF O157:NM. While no evidence toxin or expression differences between two O157...

Summary Escherichia coli O157:H7 is a zoonotic pathogen that can express type III secretion system (TTSS) considered important for colonization and persistence in ruminants. E. strains have been shown to vary markedly levels of protein secreted using the TTSS this study has confirmed high phenotype more prevalent among isolates associated with human disease than shed by healthy cattle. The variation consequence heterogeneous expression, being dependent on proportion bacteria population are...

To investigate the influence of geographical origin, age, and sex on toxicologically relevant spontaneous histopathology findings in cynomolgus macaques ( Macaca fascicularis), we performed a comparative analysis historical control data (HCD) from 13 test sites that included 3351 animals (1645 females 1706 males) sourced Mauritius, China, Vietnam, Cambodia, aged 2 to 9.5 years, 446 toxicology studies evaluated between 2016 2021. The most common were mononuclear infiltrates kidney, liver,...

The aim of this work was to characterize adaptive mucosal immune responses Escherichia coli O157:H7 at the principal site colonization in bovine species. Following experimental infection, extracts from terminal rectum samples were tested for IgA antibodies by immunoblotting against different bacterial antigens including: whole-cell E. with and without proteinase treatment, outer membrane cytoplasmic preparations, secreted protein supernatants purified O157 lipopolysaccharide H7 flagellin....

Enterohemorrhagic Escherichia coli O157:H7 has a natural reservoir in the intestinal tracts of cattle. Colonization is asymptomatic and transient, but it not clear if protective immunity induced. This study demonstrates that prior colonization induces humoral immune responses to bacterial antigens reduces shedding after experimental challenge with homologous strain.

Enterohemorrhagic Escherichia coli O157:H7 is an important intestinal pathogen of humans with a main reservoir domesticated ruminants, particularly cattle. It anticipated that the risk human infection can be reduced by controlling organism within its hosts. Several options for control E. in cattle have been proposed, but none demonstrated to successful field. Here we describe novel experimental method, based on terminal-rectum-restricted colonization described previously, eliminate fecal...

The incidence and range of spontaneous pathology findings were determined in the eyes male female control Crl:CD-1(ICR)BR mice. Data collected from 250, 430, 510, 2,266 mice dose groups 4-, 13-, 80- 104-week studies, respectively, carried out between 2005 2013. Lesions eye very rare 4- 13-week uncommon 80-week relatively higher studies. No sex predilection lesions was apparent. neoplastic observed, congenital rare. most common cataracts, retinal degeneration, mineral deposits iris,...

To further our understanding of the nonhuman primate kidney anatomy, histology, and incidences spontaneous pathology, we retrospectively examined kidneys from a total 505 control Cynomolgus monkeys (Macaca fascicularis; 264 male 241 females) aged 2 to 6 years, toxicity studies. Kidney weights, urinalysis, kidney-related clinical biochemistry parameters were also evaluated. Although functional anatomy monkey is relatively similar that other laboratory animals humans, few differences...

The authors performed a retrospective study to determine the incidences of spontaneous findings in adrenal glands control CD-1 mice. Data were collected from 2,163 mice dose groups 104-week carcinogenicity studies carried out between 2000 and 2010. Adrenal gland nonproliferative lesions more common males than females. In males, most cortical hypertrophy, atrophy, pigment deposition/pigmentation, cysts, extramedullary hematopoiesis. females, hematopoiesis, atrophy. Proliferative females...

Biotherapeutics are pharmaceutical products derived from or synthesized by biological systems. Such molecules carry the potential for immunogenicity which may lead to adverse immune responses. The cynomolgus macaque ( Macaca fascicularis) is species of choice in nonclinical safety assessment biotherapeutics. main aim this study was confirm whether mononuclear cell infiltrates at specific locations represent a generic effect biotherapeutics, and therefore result their immunogenicity....

This Proof of Concept (POC) study was to assess whether assessment whole slide images (WSI) the 2 target tissues for a contemporaneous peer review can elicit concordant results findings generated by Study Pathologist from glass slides. Well-focused WSI liver and spleen 4 groups mice, that had previously been diagnosed be an experienced veterinary toxicologic pathologist examining slides, were independently reviewed 3 pathologists with varying experience in WSIs. Diagnostic discrepancies then...