Necrotizing typhlocolitis associated with a spirochete in rheas (Rhea americana).

Necrotizing typhlocolitis was diagnosed in 13 juvenile common rheas (Rhea americana) from three separate of geographically isolated Ohio flocks, with mortality ranging from 25% to 80%. At postmortem examination, a diphtheritic membrane covered ulcerated cecal mucosa. Histologically, cecal sections showed necrosis and granulomatous-to-suppurative inflammation that extended into the submucosa and often surrounded large eosinophilic colonies of bacteria. Warthin-Starry staining showed these colonies to be composed of entangled spirochetes that invaded the submucosa and frequently were present transmurally. Similar organisms were identified by Warthin-Starry staining in the cecum of a juvenile rhea from a fourth flock that histologically had mild lymphocytic typhlitis. Scanning and transmission electron microscopy demonstrated the presence of a spirochete in the ceca. Anaerobic culture yielded a gram-negative, beta-hemolytic spirochete. Coccidia, histomonads, and Salmonella spp. were consistently absent.     

Colitis associated with Clostridium difficile in specific-pathogen-free C3H-scid mice

Soft feces and a decreased delivery rate were observed in a specific-pathogen-free (SPF) C3H-scid mouse breeding colony. Grossly, the ceca were shrunken and edematous in the affected mice. Histopathologically, severe edema in the cecal submucosa as well as infiltration of inflammatory cells in the lamina propria and submucosa of the ceca and colon were observed. No pathogenic microorganisms were detected by the routine microbiological tests. By anaerobic bacterial-examination, Clostridium (C.) difficile with toxin A was isolated from the cecal contents of the affected mice. The mice were diagnosed with C. difficile-associated colitis. This case appears to be the first report of natural infection with C. difficile in SPF mice with clinical signs.     

Experimental induction of bacterial gastritis and gastric ulcer disease in gnotobiotic swine inoculated with porcine Helicobacter-like species

OBJECTIVE: To determine whether 2 isolates of recently isolated swine-origin Helicobacter pylori-like bacteria are pathogenic in pigs and compare the signs of gastric disease induced by these isolates with those detected in H pylori- and Helicobacter heilmannii-infected pigs. ANIMALS: 36 neonatal gnotobiotic pigs. PROCEDURE: Groups of separately housed pigs were inoculated orally with swine-origin Helicobacter-like isolates 2662 or 1268, H pylori (human gastric pathogen), or a gastric homogenate from gnotobiotic swine containing H heilmannii. Noninoculated pigs were used as control animals. Clinical signs and development of homologous and heterologous antibodies against Helicobacter organisms were assessed. After euthanasia, gastric tissues were examined grossly and microscopically; Helicobacter organisms were detected by use of Warthin-Starry and immunohistochemical stains. RESULTS: Both porcine Helicobacter-like isolates colonized the stomachs of swine. Isolate 2662 was highly pathogenic; in 13 isolate 2662-inoculated pigs, gastroesophageal ulcerations developed in 9 and ulceration of the gastric glandular mucosa was detected in 5. Histologically, inflammatory gastritis consisting of multifocal to diffuse lymphocytic and plasmacytic cellular infiltrates and lymphoid follicle formation in the gastric lamina propria accompanied bacterial colonization of the gastric compartment. In contrast, H heilmannii was minimally pathogenic in that only modest inflammatory cell infiltrates were seen. Gastroesophageal or mucosal ulcers were not evident in pigs inoculated with H heilmannii. CONCLUSIONS AND CLINICAL RELEVANCE: These data indicate that swine-origin H pylori-like bacteria can be pathogenic in pigs and suggest that porcine gastric disease may be mediated, in part, by colonization of the stomach by swine-origin H pylori-like bacteria.     

虾青素对小鼠结肠急性氧化损伤的保护作用

试验旨在研究虾青素对脂多糖(LPS)诱导的小鼠急性结肠炎及氧化应激的影响。选择 6 周龄健康雄性 ICR 小鼠 32 只,随机分为 4 组,其中对照组和 LPS 组小鼠连续 15 d 灌胃橄榄油,虾青素组和虾青素保护组小鼠连续 15 d 灌胃 50 mg/kg 虾青素,15 d 后对照组和虾青素组腹腔注射生理盐水,LPS 组和虾青素保护组腹腔注射 1 mg/kg LPS,3 h 后处死,采集血液及结肠组织。ELISA 和荧光定量 PCR 检测血清及结肠中炎性因子和抗氧化酶水平,生物化学法测定结肠中氧化水平,Western blot 检测结肠中 p-NF-κB p65 蛋白相对表达量,HE 染色观察结肠病理形态学变化。结果表明:与对照组相比,LPS 组小鼠血清和结肠组织中炎症因子的表达及 NF-κB p65 蛋白的活化均显著升高(P<0.05),组织抗氧化水平低(P<0.05),结肠黏膜损伤严重;与 LPS 组相比,保护组小鼠血清和结肠组织中炎症因子表达及 NF-κB p65 蛋白的活化均显著降低(P<0.05),组织抗氧化水平高(P<0.05),且结肠黏膜损伤程度低。虾青素可保护小鼠结肠黏膜结构,通过抑制 NF-κB信号通路降低机体中炎性因子的分泌,提高组织抗氧化水平,缓解 LPS 引起的急性结肠损伤。     

A comparison of the morphologic effects of Serpulina hyodysenteriae or its beta-hemolysin on the murine cecal mucosa.

Studies were carried out to compare the early morphologic changes in the cecal mucosa of mice either infected with Serpulina hyodysenteriae or exposed to the beta-hemolysin of S. hyodysenteriae. Sixty-five 12-24-week-old C3H/HeOuJ mice were infected with S. hyodysenteriae by gastric intubation. Two mice were necropsied every hour for 30 hours following infection. S. hyodysenteriae was isolated from the cecal contents of each mouse at all time points. Macroscopic lesions were first apparent at 14 hours postinfection (PI), and light microscopic lesions were first apparent at 10 hours PI, earlier than has been previously reported. Ultrastructural changes, first evident at 6 hours PI, included disarray and loss of microvilli and terminal web, with dilatation of intercellular spaces. Luminal bacteria were translocated through epithelial cells to the lamina propria, where capillaries exhibited changes indicative of increased permeability. In another experiment, solutions containing between 2,500 and 25,000 hemolytic units of purified S. hyodysenteriae hemolysin were placed within the lumen of surgically closed murine ceca (n = 10); ceca were collected for examination 3 hours following treatment. Ultrastructural changes consisted of loss of microvilli and terminal web and marked vacuolation and exfoliation of epithelial cells. Significant numbers of necrotic and apoptotic epithelial cells were present, and epithelial cells internalized moderate numbers of bacteria. The hemolysin of S. hyodysenteriae induces some of the same early ultrastructural changes in the cecal epithelium of mice as occur following infection with S. hyodysenteriae. Based on the observed bacterial translocation, luminal bacteria also appear to play a unique role in lesion development in this model.     

Adenoviral gizzard erosion in commercial broiler chickens

Pathologic and immunohistochemical changes caused by group I of the fowl adenovirus (FAV) serotype-1 99ZH strain, isolated from broiler chickens exhibiting gizzard erosion, were investigated in commercial broiler chickens. One hundred twenty-two chickens were inoculated with the strain by both oral and ocular routes at 1, 3, or 5 weeks of age and euthanatized for necropsy within 4-18 days of inoculation. Focal gizzard erosions were observed in the inoculated chickens of each age group. A histologically degenerative koilin layer, necrotic mucosa, intranuclear inclusion bodies in the glandular epithelial cells, inflammatory cell infiltrations in the lamina propria, submucosa, and a muscle layer were seen in the gizzards. Immunohistochemical staining showed evidence of FAV antigens in the intranuclear inclusion bodies. These findings were recognized regardless of their maternal antibody levels for FAV serotype-1. Gizzard lesions appeared later in the lower-dose-inoculated chickens than in the higher-dose-inoculated chickens. Numerous CD3-positive cells and IgY-positive plasma cells were seen in the gizzard lesions. In 5-week-old chickens the heterophil infiltrations in the lesions were milder than in younger chickens. Intranuclear inclusion bodies also were observed in the epithelial cells of the ileum or cecal tonsils of some chickens. Thus, this study shows that FAV-99ZH causes adenoviral gizzard erosion in broiler chickens without hepatic or pancreatic lesions and that cell infiltration is more severe than in dietary gizzard erosions.     

Pathological changes of tracheal mucosa in chickens infected with fowl pox virus

Five-week-old chickens were inoculated with fowl pox (FP) virus and killed on various days through day 30 postinoculation (PI). The trachea was examined with a scanning electron microscope (SEM), a transmission electron microscope (TEM), and a light microscope (LM). From day 3 PI, small focal lesions of the mucosa were detected. On day 7 PI, upon formation of cytoplasmic inclusion bodies, epithelial cells proliferated profusely, enlarged, and formed clusters like papillomata. The disease proceeded to the gradual disruption of the lesions owing to the collapse of individual degenerating epithelial cells. Total desquamation of the lesions was observed. Ultrastructural examination revealed that the surface degenerating epithelial cells of the lesions ruptured and had virus particles inside. These changes were accompanied by severe inflammatory reaction. Thereafter, epithelial cells regenerated actively and the mucosa recovered by day 27 PI.     

Blue-green endoscopy in a dog presenting chronic vomiting-regurgitation

A 2-year-old male Maremma sheepdog presenting with chronic vomiting-regurgitation was examined at the University Veterinary Teaching Hospital, Camerino University. An oesophagogastroscopy with a single blue + green (BG) filter restricting wavelengths from 400 to 550 nm was carried out. A conventional white light endoscopy showed a dilated oesophagus with mildly diffuse erythematous mucosa (more accentuated proximal to the cardia); some portions of the gastric mucosa were covered with fluids and appeared only slightly erythematous. A blue green endoscopy highlighted the oesophageal lesions in dark blue, which made them appear more clearly defined from the remaining mucosa. In the gastric antrum, a small, slightly darker blue roundish area was visible. This area did not show up under the white light endoscopy. A histopathological assessment of biopsy specimens from the distal oesophagus, antrum (including the area highlighted only by BG endoscopy) and gastric body showed chronic-active hyperplastic esophagitis and superficial squamous epithelial dysplasia, while gastric samples showed severe diffuse hyperaemic gastritis of the antrum and superficial diffuse atrophy of the gastric body. The authors believe that the use of a BG endoscopy could be useful in veterinary medicine to increase the diagnostic potential of endoscopic assessment in animals.     

Histological and immunohistochemical detection of different Helicobacter species in the gastric mucosa of cats.

Detailed histopathological evaluation of the gastric mucosa of Helicobacter-infected cats is complicated by the difficulty of recognizing Helicobacter organisms on hematoxylin and eosin (HE)-stained sections and the ability of multiple Helicobacter species to infect cats. In this study, the presence and localization of different species of Helicobacter in the stomachs of cats was investigated using silver staining and immunohistochemistry. Five groups containing 5 cats each were established (group 1: urease negative and Helicobacter free; groups 2, 3, 4, and 5: urease positive and infected with Helicobacter heilmannii, unclassified Helicobacter spp., Helicobacter felis, and Helicobacter pylori, respectively). Gastric samples were evaluated by HE and silver staining and by immunohistochemistry with 3 different anti-Helicobacter primary antibodies. Helicobacter were detected by Steiner stain in all infected cats at the mucosal surface, in the lumen of gastric glands, and in the cytoplasm of parietal cells. In silver-stained sections, H. pylori was easily differentiated from H. felis, H. heilmannii, and unclassified Helicobacter spp., which were larger and more tightly coiled. No organisms were seen in uninfected cats. Helicobacter antigen paralleled the distribution of organisms observed in Steiner-stained sections for 2 of the 3 primary antibodies tested. The antisera were not able to discriminate between the different Helicobacter species examined. A small amount of Helicobacter antigen was present in the lamina propria of 3 H. pylori-, 3 H. felis-, and 1 H. heilmannii-infected cat. Minimal mononuclear inflammation was present in uninfected cats and in those infected with unclassified Helicobacter spp. and H. heilmannii cats. In H. felis-infected cats, lymphoid follicular hyperplasia with mild pangastric mononuclear inflammation and eosinophilic infiltrates were present. The H. pylori-infected cats had severe lymphoid follicular hyperplasia and mild to moderate mononuclear inflammation accompanied by the presence of neutrophils and eosinophils. These findings indicate that Steiner staining and immunohistochemistry are useful for detecting Helicobacter infections, particularly when different Helicobacter species can be present. Monoclonal antibodies specific for the different Helicobacter species could be important diagnostic aids. There appear to be differences in the severity of gastritis in cats infected with different Helicobacter species.     

Ultrastructural study of the equine cecum during onset of laminitis

The morphologic and pathologic changes which occurred within the cecal mucosa of 4 horses during the onset of laminitis were determined from cecal biopsy materials obtained via a cecal fistula; the laminitis was induced with carbohydrate overload. The cecal epithelial mucosa specimens were obtained at 0 (base line), 24, 32, 48, and 72 hours after horses were given carbohydrate overload, and these were fixed and subsequently photographed. Changes in the cecal epithelium were examined by transmission electron and scanning electron microscopies. These histopathologic changes indicated that the mucosal barrier was substantially damaged by the carbohydrate overload.     

Role of Helicobacter felis in chronic canine gastritis.

Five gnotobiotic Beagle dogs were orally inoculated with a pure culture of Helicobacter felis. The remaining two littermates served as contact controls. Thirty days after infection, all animals were euthanatized and specimens were collected for evaluation. In infected dogs, H. felis was recovered from all areas of the stomach. Colonization was heaviest in the fundus and antrum. H. felis was not cultured from any segment of the gastrointestinal tract distal to the duodenum. Two weeks after infection, all five infected dogs had detectable IgM and IgG serum antibody to H. felis, whereas control dogs had no measurable H. felis serum antibody throughout the study. Histopathologic changes in the stomachs of infected dogs included large numbers of lymphoid nodules throughout all regions of the gastric mucosa and were most numerous in the fundus and body. A mild, diffuse lymphocytic infiltrate with small numbers of plasma cells and eosinophils was also present in the subglandular region of all portions of the gastric mucosa. Electron microscopic examination revealed large numbers of spiral-shaped H. felis in gastric mucus adjacent to or superimposed over the areas of inflammation. Occasionally, however, H. felis was observed within the canaliculi of gastric parietal cells. Histopathologic changes in the stomachs of the contact control dogs were limited to focal infiltrates of eosinophils and small aggregates of lymphocytes in the subglandular portions of the gastric mucosa in one animal. Infection with H. felis is a likely cause of naturally occurring lymphofollicular gastritis.     

Comparison of gastritis and gastric epithelial proliferation in Helicobacter heilmannii-infected nude and BALB/c mice

Gastric mucosal hypertrophy/nodular hyperplasia occurs as a consequence of Helicobacter infection in mice and humans. The pathogenesis of this hyperplastic response is not understood. To determine the role of host cellular immunity in gastric mucosal hypertrophy/hyperplasia, 6-8-week-old female euthymic BALB/c (n = 30) or NIH athymic nude (n = 40) mice were inoculated with H. heilmannii. Equal numbers of uninoculated mice of each strain served as controls. Mice from each group were euthanatized at 0.5, 6, 12, and 18 months postinoculation (PI). Lymphoplasmacytic gastritis and lymphoid follicle development were less severe in nude mice than in euthymic mice at <6 months PI. The prevalence of gastritis at 0.5, 6, 12, and 18 months PI was 0%, 17%, 67%, and 88%, respectively, in infected nude mice and 33%, 83%, 71%, and 100%, respectively, in infected BALB/c mice. CD4+ T cells in infected nude mice were evident at > or =6 months PI but were less numerous than in infected BALB/c mice at comparable time intervals. However, numbers of CD4+ T cells increased substantially throughout the experiment in infected BALB/c mice. The prevalence of nodular mucosal hyperplasia at 0.5, 6, 12, and 18 months PI was 0%, 0%, 33%, and 20%, respectively, in infected nude mice and 0%, 33%, 80%, and 80%, respectively, in infected BALB/c mice. Nodular hyperplasia occurred in association with the appearance of chronic lymphoplasmacytic inflammation and CD4+ T cells at 12 and 18 months PI in nude mice. H. heilmannii-associated gastritis and mucosal remodeling is reduced in immunodeficient mouse strains lacking normal CD4+ T cell numbers as compared with the response in immunocompetent mice. Additionally, CD4 immunocompetence is an integral aspect of the mucosal hypertrophy/nodular hyperplasia in experimental H. heilmannii-associated disease of mice.     

Experimental Infection of Pigs with ‘<Emphasis Type="Italic">Candidatus</Emphasis> Helicobacter suis’

‘Candidatus Helicobacter suis’ is a spiral-shaped bacterium that colonizes the stomach of more than 60% of slaughter pigs. The role of ‘Candidatus Helicobacter suis’ in gastric disease of pigs is still unclear. Experimental studies in pigs are lacking because this bacterium is unculturable until now. An inoculation protocol using ‘Candidatus Helicobacter suis’ infected mouse stomach homogenate was used to reproduce the infection in pigs. Control animals were inoculated using negative mouse stomach homogenate. Pigs were inoculated three times with one-week intervals and euthanized 6 weeks post inoculation. Tissue samples were taken from different mucosal stomach regions to detect ‘Candidatus Helicobacter suis’ by PCR and urease test. Mucosal inflammation was evaluated on formalin-fixed tissue samples. Lesions in the pars oesophagea were scored macroscopically. Infection was succesful in all challenged animals, with the antrum and the fundus being predominantly positive. Infection was associated with infiltration of lymphocytes and plasma cells in the antral mucosa, evolving to follicular gastritis. No apparent inflammation of the fundic stomach region was detected in the infected animals. A clear link between ‘Candidatus Helicobacter suis’ and pars oesophageal lesions could not be found.     

Morphometric analysis of enteric lesions in C3H/HeN mice inoculated with Serpulina hyodysenteriae serotypes 2 and 4 with or without oral streptomycin pretreatment.

The segmental distribution and sequential progression and the role of the indigenous bacterial flora in the development of enteric lesions associated with Serpulina hyodysenteriae infection in laboratory mice have not been defined. We examined the distribution and sequential morphometric changes in the large intestine of mice orally inoculated with S. hyodysenteriae serotypes 2 and 4. To determine the role of colonization resistance conferred by the indigenous bacterial flora, 40 female C3H/HeN mice were administered water alone or water containing 5 mg/mL streptomycin sulfate ad libitum for seven days prior to orogastric inoculation either with S. hyodysenteriae or sterile trypticase soy broth (TSB). Clinical signs were monitored daily and three mice per group were necropsied on postinoculation days (PID) 7 and 14 for pathological assessment of the cecum, proximal colon, transverse colon, and descending colon, and bacteriological culture of the cecum for S. hyodysenteriae. Weekly pooled fecal samples were collected from each group for determination of total numbers of anaerobe bacteria. Gross examination revealed soft fecal pellets on PID 7 and 14 and catarrhal typhlitis on PID 14, irrespective of streptomycin pretreatment. The recovery rates of S. hyodysenteriae from the ceca of serotype 2- and serotype 4-inoculated mice was 100 and 91.7%, respectively. Statistically significant differences in morphometric changes between TSB- and S. hyodysenteriae-inoculated mice were present on PID 7 and 14 and were restricted to the cecum. Although oral administration of streptomycin for seven days prior to S. hyodysenteriae inoculation resulted in a significant reduction in the numbers of fecal anaerobes, it did not affect the colonization, distribution, severity, or progression of cecal lesions.     

Fatal gastrointestinal infection with 'Flexispira rappini'-like organisms in a cat

A 4-month-old male British Blue cat with catarrhal to haemorrhagic enteritis showed massive colonization of the stomach, small intestine and caecum with spiral-shaped bacilli. In the stomach, organisms were located in foveolae and gland lumina and within unaltered and degenerate epithelial cells. Inflammatory infiltration was moderate and T cell dominated. In the intestine, bacilli were found in the gut lumen, berween villi, in crypt lumina and within epithelial cells. Degeneration of crypt epithelial cells as well as crypt dilation and moderate to massive macrophage-dominated infiltration of the mucosa and submucosa were observed. Immunohistochemically, bacilli were positive with an antibody against Helicobacter. Ultrastructurally, the organisms strongly resembled 'Flexispira rappini', a spiral-shaped Helicobacter species known as a normal intestinal colonizer in dogs and mice.     

Colonization strategy of Campylobacter jejuni results in persistent infection of the chicken gut

Although poultry meat is now recognized as the main source of Campylobacter jejuni gastroenteritis, little is known about the strategy used by the bacterium to colonize the chicken intestinal tract. In this study, the mechanism of C. jejuni colonization in chickens was studied using four human and four poultry isolates of C. jejuni. The C. jejuni strains were able to invade chicken primary cecal epithelial crypt cells in a predominantly microtubule-dependent way (five out of eight strains). Invasion of cecal epithelial cells was not accompanied by necrosis or apoptosis in the cell cultures, nor by intestinal inflammation in a cecal loop model. C. jejuni from human origin displayed a similar invasive profile compared to the poultry isolates. Invasiveness of the strains in vitro correlated with the magnitude of spleen colonization in C. jejuni inoculated chicks. The C. jejuni bacteria that invaded the epithelial cells were not able to proliferate intracellularly, but quickly evaded from the cells. In contrast, the C. jejuni strains were capable of replication in chicken intestinal mucus. These findings suggest a novel colonization mechanism by escaping rapid mucosal clearance through short-term epithelial invasion and evasion, combined with fast replication in the mucus.     

Pathogenesis of rotavirus infection in various age groups of chickens and turkeys: clinical signs and virology

Age-related susceptibility patterns of turkeys, broilers, and specific pathogen-free (SPF) White Leghorn chickens to experimentally induced infection with turkey or chicken rotavirus isolates were compared. The following determinants were evaluated: clinical signs, onset and duration of virus production, viral titers, involvement of intestinal villi in the replication of the virus, and the development of antibodies against the virus. Older turkeys and chickens were more susceptible than were their younger counterparts, turkeys were more susceptible than were broiler and White Leghorn chickens (regardless of age), and broiler chickens were slightly more susceptible than were age-matched White Leghorn chickens. Turkeys developed diarrhea, accompanied by high viral titers within 1 day after inoculation with virus. Viral antigen was found in the epithelial cells of the intestinal villi throughout the intestinal tract and some cells of the cecal tonsils. Antibodies could be detected as early as 4 to 5 days after inoculation. These findings were more pronounced in turkeys inoculated at 112 days of age than in birds inoculated at a younger age. Age-related susceptibility patterns were similar in White Leghorn and broiler chickens. Infection was subclinical in birds less than 56 days old, whereas older birds developed soft feces. Egg production in the White Leghorn chickens decreased after being inoculated with virus at 350 days of age.