Effect of bicozamycin on the eradication of Shiga toxin-producing Escherichia coli in calves

Fifty-nine calves, aged 11 days to 9 months, from three farms breeding Japanese Black beef cattle in Miyazaki Prefecture, Japan, were examined for the presence of Shiga toxin-producing Escherichia coli (STEC). A high prevalence of STEC was detected among calves, with 45 (76.3%) animals carrying STEC including different serogroups (O26, O74, O111, O114, O119, O127, O153, O157, and ONT) and toxin types. The number of STEC in the feces was estimated by a combined method involving enumeration of colony-forming units by a plate-most-probable-number (plate-MPN) technique and polymerase chain reaction for the detection of Shiga toxin genes. Fecal shedding ranged from 10(1) to 10(10) MPN/g feces. To evaluate the safety and efficacy of bicozamycin (BCM: previously named as bicyclomycin) in eradicating STEC, 30 calves carrying STEC with or without diarrhea were examined. Fifteen calves were treated orally with BCM (10 mg/kg/day) once daily for 5 days, and the other 15 were untreated. Twenty-four hours after the last dose, fecal specimens were collected from both groups to compare the number of coliforms and STEC with those before treatment. BCM-treated animals had a significantly lower number of coliforms and STEC compared to the untreated calves. The STEC eradication rate was 86.6% (13/15) in the BCM-treated group, compared to 0% (0/15) in the control group. The corresponding cure rates for diarrhea were 87.5 (7/8) and 0% (0/3), respectively. No adverse reactions were observed in the calves during treatment. It is concluded that BCM is an effective agent for the eradication of STEC in calves with or without diarrhea.

Detection of Akabane viral antigens in spontaneous lymphohistiocytic encephalomyelitis in cattle

A 5-month-old Japanese black bull calf and twenty-seven 1-27-day-old calves exhibiting neurological signs between August and October 1998 were examined. The bull calf exhibited rapid breathing, fever, hypersensitivity, and ataxia and was euthanized 4 days after the onset of symptoms. The 27 calves primarily exhibited ataxia, and 15 had arthrogryposis. Histological examination of the bull calf revealed perivascular infiltraction by mononuclear cells, diffuse to multifocal gliosis, and neuronal necrosis in the brain and spinal cord. Multiple malacic foci were found in the midbrain in 5 cases. In contrast, in the 15 calves necropsied in October, there were fewer inflammatory changes, but there was neuronal cell loss in the ventral horn and a decrease in myelinated axons in the lateral and ventral funiculi. Immunohistochemical examination using a rabbit antiserum against Akabane virus strain OBE-1 revealed a large amount of viral antigen in the degenerating neurons and glial cells of the bull calf, mainly in the spinal gray matter. Small amounts of viral antigen in swollen axons and a few glial cells were found in 5 of 27 calves. Thirteen of the 27 calves had high neutralization antibody titers against the Akabane virus, whereas there was no significant antibody titer in most of the calves necropsied during August. The present study revealed that viral antigen detection was very useful for the diagnosis of Akabane diseases in the 5-month-old bull calf that was suspected to be infected postnatally, while it had limited usefulness in the other young calves.

Intestinal spirochetosis in wild sika deer (Cervus nippon yesoensis) infected with Brachyspira species

Seven adult free-ranging sika deer (Cervus nippon yesoensis) were examined by histology, immunohistochemistry and electron microscopy for intestinal spirochetal infection. Histologically epithelial and goblet cell hyperplasia and edema of the lamina propria mucosa with macrophage and lymphocyte infiltration were observed in the cecum and colon in 6 of the 7 deer. Numerous argyrophilic spirochetes were present in the crypts and some had invaded epithelial and goblet cells and caused degeneration. Immunohistochemically the organisms stained positively with polyclonal antisera against Brachyspira (Serpulina) hyodysenteriae and B. pilosicoli. Ultrastructurally they were 6-14 microm long, 0.2-0.3 microm wide and had 4-6 coils and 13 axial filaments per cell; such features were closely similar to those in the Brachyspira species. These results showed that the spirochetes were capable of inducing enteritis in deer and this intestinal spirochete infection might already be prevalent among wild sika deer in Japan. There is a possibility that this spirochetal colitis is a new syndrome in sika deer and that the same and/or similar spirochetes have infected ruminants, including sika deer and cattle.

Isolation of porcine epidemic diarrhea virus in porcine cell cultures and experimental infection of pigs of different ages

This paper describes the isolation of porcine epidemic diarrhea (PED) virus in Vero and porcine cell cultures, and the influence of age on disease in experimental infection. PED virus was isolated from the small intestine of piglets inoculated with PED samples and cultured in Vero, porcine bladder and kidney cells propagated in collagen-coated tissue culture plates in maintenance medium (MM) containing trypsin. In porcine bladder and kidney cell cultures inoculated with isolated PED virus, cytopathic effects (CPE) including cell fusion were detected. Specific brilliant fluorescence was observed in the cytoplasm of these cells. Two- and 7-day old, and 2-, 4-, 8- and 12-week old specific pathogen-free (SPF) pigs were orally inoculated with PED virus isolated from an outbreak. All 2- and 7-day old pigs inoculated developed severe watery diarrhea from post-inoculation day (PID) 1 and died between PID 3 and 4. Although three of five 2-week old pigs developed diarrhea on PID 1-4, they eventually recovered. In the 4-week old group, three of five pigs had mild diarrhea for 1-2 days. None of the 8- and 12-week old pigs showed any clinical signs. Antibodies against PED virus were detected in all surviving pigs by virus neutralization (VN) test and immunofluorescence assay (IFA). Therefore, there is an age-dependent resistance to pathogenic PED virus infection in pigs.

[Estimation of probiotics by infection model of infant rabbit with enterohemorrhagic Escherichia coli O157:H7]

We examined the preventative effect against enterohemorrhagic Escherichia coli O157:H7 (EHEC) infection in rabbits on administration of probiotics contained in Streptococcus faecalis, Clostridium butyricum and Bacillus mesentericus. The probiotics were administered to 5 days old Japanese white rabbits throughout the experiment. Inoculation of 10(6) colony forming units (CFUs) of EHEC per rabbit was tried 8 days after birth. Three days after EHEC inoculation, in the control group (not administered probiotics), diarrhea was observed in approximately 80% of the rabbits, on the other hand, in the group administered probiotics, rabbits showed diarrhea in 15%. In necropsy, the number of EHEC in the contents of the cecum and the number of attaching and effacing (AE) lesions were fewer in the probiotics group than in the control group. These results suggest that infant rabbits are useful as a colitis model for EHEC, and the probiotics are effective for the prevention of the growth of EHEC in the intestine and for diarrhea.

A novel developmental process of intestinal epithelial lesions in a calf infected with attaching and effacing Escherichia coli

A comparative study on the adhesion of attaching and effacing Escherichia coli (AEEC) to the enterocytes between the colon of a calf and the jejunum of a piglet showed differences in the developmental process of attaching and effacing (AE) lesions. In the calf, pedestals consisted of fused microvilli, while in the piglet they developed from the apical epithelial cell membranes after effacing microvilli. Microvilli adjacent to the AEEC attachment site were atrophic in the calf, whereas they were elongated in the piglet. The production of AE lesions in the calf may be indicative of a novel developmental process with AEEC infection.

A chick model for the study of "attaching and effacing Escherichia coli" infection

Young chicks were experimentally infected with 6 strains of AEEC isolated from calves, pigs, chicks, and humans. AEEC colonized the cecum of chicks and induced the AE lesions on the mucosal surface. In the early stages of the AE lesions, AEEC attached to the enterocyte were enfolded with the microvilli. In the advanced stages, microvilli and cytoskeletons of the enterocytes were disrupted, and cytoplasmic cups and pedestal-like protrusions were formed on the cell surface. The AE lesions interconnected with the adjacent lesions, and it formed the network on the mucosal surface. Leukocytes infiltrated in the mucosa associated with AE lesions, and lymphatic nodules also developed. The results of these studies support the conclusion that chicks can be used as a model for the study of the lesions caused by AEEC.

A new adherent form of an attaching and effacing Escherichia coli (eaeA+, bfp-) to the intestinal epithelial cells of chicks

The adherent site of "attaching and effacing Escherichia coli" (AEEC; O103: H-, SK-1 strain) on the intestinal epithelial cells of chicks infected naturally and experimentally was ultrastructurally investigated. The eaeA gene was detected by polymerase chain reaction in the SK-1 strain of E. coli isolated from the intestinal content of a chick infected naturally, however, the bundle-forming pilus (bfp) gene could not be detected. The SK-1 strain (bfp-) of AEEC could attach to the intestinal epithelial cell and induce attaching-effacing lesions in the intestine of chicks. Transmission electron microscopy revealed numerous pilus-like microfilaments in the space between colibacilli and the membranes of the intestinal epithelial cells. The present study suggests that SK-1 strain (eaeA+, bfp-) may attach closely to the intestinal epithelial cells by a novel adhesion different from bfp.

Natural infection with attaching and effacing Escherichia coli (O 103:H-) in chicks

The existence of natural infection with attaching and effacing Escherichia coli (AEEC) in chicks was reported. Numerous Gram-negative bacilli were attached to the enterocyte in association with lesions characterized on a wavy appearance of the mucosal surface in the intestines of six chicks. Immunohistochemically, these bacteria reacted positively with antiserum to Escherichia coli (O 103). By electron microscopy, numerous colibacilli were seen to be closely attached to the surface membranes of the enterocytes. In regions of bacterial attachment, almost all cell microvilli were effaced, and some of the remaining ones were elongated and/or disoriented. Part of the cell membrane formed a cup invagination and pedestal-like protrusion associated with the attached bacteria. A concentration of electron-dense material was seen beneath the adherent organisms. Bacteriologically, numerous E. coli (O 103:H-) were isolated from the jejunal contents of two chicks and the E. coli did not produce verotoxin or enterotoxin. The characteristic lesions could also be induced in the cecal mucosa of young chicks experimentally inoculated with the isolated E. coli. This is the first report of natural infection in chicks with AEEC.

An immunohistochemical investigation of porcine epidemic diarrhoea

A sudden outbreak of epidemic diarrhoea of piglets occurred in Japan, the principal features being watery diarrhoea, dehydration and high mortality in newborn animals. The microscopical lesions were villous atrophy in the small intestine, the villous enterocytes being vacuolated and cuboidal in shape. The villus-crypt ratio was severely reduced, varying from 1:1 to 3:1. Transmission electron microscopy showed numerous coronaviruses within the cytoplasm of enterocytes and among microvilli. Specific antigens of porcine epidemic diarrhoea (PED) virus were detected in the cytoplasm of enterocytes by the streptavidin-biotin (SAB) technique. Infected cells, which were most abundant in the villous epithelia of the jejunum and ileum, were present in small numbers in the large intestine, the crypt epithelia, the lamina propria and Peyer's patches. The study suggests that the SAB technique is useful for the diagnosis of PED.

Partial characterization of larval antigens of Strongyloides papillosus by western blot analysis

Western blotting was used to analyse the antigens in extracts of adult and infective larvae (SIL) of Strongyloides papillosus with serum of infected rabbits. Several proteins in both the extracts reacted with immunoglobulin G in the serum. A protein of about 16 kDa in the extract of SIL showed an especially strong reaction. No cross-reaction was observed among proteins in the extracts of adult worms of such cattle helminths as Fasciola gigantica, Homalogaster paloniae, Trichuris discolor and Setaria digitata to S. papillosus-infected rabbit serum. The cuticle of the worms and substances in the worm tracks showed positive reaction with the immunoperoxidase test on SIL with the serum.

Experimental infection of young chicks with attaching and effacing Escherichia coli

Young chicks were inoculated with six different strains of attaching and effacing Escherichia coli isolated from the feces of calves, pigs, chicks, and humans. Colibacilli of some serotypes had colonized the cecum of chicks by 7 days after inoculation. The characteristic lesions associated with bacterial attachment were also seen on the mucosal surface of the cecum. Electron microscopy revealed numerous colibacilli closely attached to the surface membrane of enterocytes. Cell membranes formed cups and pedestals at the base of the attached bacilli. The results of this study support the conclusion that young chicks can be used as a model for the study of the lesions caused by attaching and effacing E. coli strains.

Radiopacity of dental cements

The radiopacity of zinc phosphate, polycarboxylate and glass ionomer dental luting materials was determined and the values were compared with those of tooth substrates. The radiographs of the 2 mm thick specimens were taken together with tooth slices and pure aluminum step wedges. The radiographic density of the specimens was measured using a densitometer and expressed in terms of the equivalent thickness of aluminum per unit thickness of material. All the zinc phosphate and polycarboxylate cements showed radiopacity values greater than that of enamel (3.5), while one glass ionomer material showed a radiopacity value lower than that of dentin (2.0). A radiopacity value greater than 3.5 may be desirable for the detection of luting materials or for their distinction from decayed tooth structure on the dental radiograph.

Sarcoid granuloma-like lesions in the lungs of broiler chicks

Sarcoid granuloma-like lesions were observed in the lungs of two broiler chicks showing depressed growth. Multinucleated giant cells in the lesions often contained foreign bodies comprising amorphous and laminated material. These were morphologically similar to Schaumann bodies found in human sarcoidosis. This is the first report of sarcoid granuloma-like lesions and Schaumann body-like material in chickens.

Radiopacity and physical properties of titanium-polymethacrylate composite

Titanium-polymethacrylate composite was prepared as an x-ray-opaque filler for composite core materials. The base monomers of the composite were 2,2-bis [4-(3-methacryloyloxy-2-hydroxypropoxy) phenyl] propane (Bis-GMA) and triethyleneglycol dimethacrylate (TEGDMA). Pure titanium powder was used as a radiopaque element. Two functional methacrylates--isopropyl dimethacryloyl isostearoyl titanate (KR-7) and 4-methacryloyloxyethyl trimellitate anhydride (4-META)--were adopted as couplers of titanium powder. The radiopacity of composites was determined in terms of their equivalent thickness of aluminum per unit thickness of material. Compressive and transverse strengths of the composites were measured by use of coupled and untreated titanium fillers. The composites that contained 70% and 80% titanium by weight showed more radiopacity than enamel and less than amalgam. Radiopacity was controlled by the content of titanium filler in the composite. The decrease in compressive and transverse strengths of the composites was 0.7 to 15.9% and 43.7 to 52.9%, respectively, after one year's immersion in water. The decrease in transverse strength was remarkable; however, this deterioration was diminished by use of both KR-7 and 4-META as couplers for titanium. Thus, prepared titanium-polymethacrylate composite may be used as a radiopaque composite filler for self-curing composite core materials.

[Chick embryo culture using duck egg shell--first successful hatch ]

The suitability of duck egg shell (DES) for chick embryo culture was investigated. Chick embryos were transferred into DESs with all egg contents after 3 days of normal incubation and cultured. The vessels made of polyethylene cling film were used for shell-less control. Among 35 embryos cultured in DESs, 21 survived until 16 days of incubation (13 days after transfer) and finally 3 newly hatched chicks were obtained at 22 days of incubation. One of them died 4 days later, but remaining two became full-grown cocks showing normal body weight and production of fertile sperms. Among 37 embryos cultured in polyethylene vessels, none survived over the period of 19 days of incubation. It is suggested that DES culture system may be useful for the various experiments using chick embryos.

Diarrhea induced by Treponema hyodysenteriae: a young chick cecal model for swine dysentery

The experimental infection of 25 young chicks with Treponema hyodysenteriae was carried out. Treponemes were isolated from 21 of 25 chicks on day 21 after inoculation. The ceca of chicks infected with treponemes were atrophied. The lumen was filled with a white watery fluid instead of digested feed. In some infected chicks, a cecal core was observed with the fluid in the cecum. The cecal core was grayish, hard, and rod shaped. It consisted of eroded cells and debris of treponemes and resembled the pseudomembrane. Bloody mucus was also observed in one chick. The thickness of the mucosae in 17 of 25 chicks were markedly increased. The histological changes were classified into two types. In the case of regressive changes of epithelial cells which mean severe erosion, the laminae propriae were exposed. Hemorrhage, edema, and heterophil infiltration in the laminae propriae were also confirmed. Numerous treponemes were observed within the edematous area under the remaining epithelia and also invaded the epithelial cells and laminae propriae. In the other case, progressive changes, that is, hyperplasia of mucosal epithelial cells and elongation of the crypt, were observed. The epithelia consisted mainly of cuboidal basophilic cells, mitotic cells, and goblet cells. The mitotic cells increased in number and were also observed near the superficial luminal surface of the ceca. Mucous goblet cells were also considerably increased in number. The erosion of superficial luminal epithelial cells was not so severe, but edema in laminae propriae was frequently observed. Electron-microscopic observation demonstrated that the basophilic epithelial cells were polyribosome rich, mitochondria poor, and lipid droplet poor. Furthermore, tonofibril-like structures under the terminal web in cytoplasms were lost, and numerous membrane-bound vesicles at the terminal web with free ribosomes were observed. In places, a number of vesicles were observed between microvilli, and some vesicles were released from the apical cytoplasm of epithelial cells. Microvilli also became scarce and irregular. The junctional complexes between cuboidal cells became unclear, the interdigitations between cuboidal cells became loose, and the intercellular spaces were widened. In conclusion, the appearance of numerous membrane-bound vesicles at the terminal web and the dilated intercellular space indicates increased secretion of water and electrolytes, and the abnormal proliferation of such immature epithelial cells indicates impaired absorption. On the basis of our findings, we can say that diarrhea induced by T. hyodysenteriae can be developed by synergism between impaired absorption and increased secretion by intestinal mucosae with hyperplastic immature epithelial cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Enteropathogenicity of Treponema hyodysenteriae in young chicks

Observation by scanning electron microscopy served to demonstrate that Treponema hyodysenteriae colonized the cecal mucosa of young chicks on day 3 after inoculation and produced lesions from 9 days after inoculation. Severe and clearly visible lesions were present on the cecal mucosa of all chicks necropsied 18, 21, and 24 days after inoculation. Severe lesions such as roughness of mucosal surface and disappearance of the mucosal foldings were observed at low magnification. The lesions were characterized by a destruction of superficial epithelial cells and dilation of crypt orifices. The dilated orifices of crypts were clearly observed, and the number of the crypts increased as compared with that of the crypts on the cecal surface in non-infected chicks. At high magnification, mucosal epithelial cells were found to be desquamated and the surface of the lamina propria mucosae had appeared. Numerous treponemas became visible on the surface of damaged epithelial cells and on the surface of the lamina propria mucosae.

Investigations into the location of Treponema hyodysenteriae in the cecum of experimentally infected young broiler chicks by light- and electronmicroscopy

Numerous Treponema hyodysenteriae were present both on the mucosal surface and in the deep crypts of the cecum of young broiler chicks 7 and 14 days after inoculation with the treponemes. The treponemes in the ceca of chicks inoculated with 10(8) cells were observed more frequently than those of chicks inoculated with 10(7) cells. The treponemes in the ceca were observed by light microscopy, scanning electron microscopy and transmission electron microscopy. The lesions were primarily confined to the cecum. Desquamation of epithelial cells, edema, leukocytic infiltration and hemorrhage were observed in the mucosae.