Comparison of the replication of distinct strains of human coronavirus OC43 in organotypic human colon cells (Caco-2) and mouse intestine

Three strains of human coronavirus (HCV) OC43 were compared for their ability to cause enteric infections and to induce interferon alpha (IFN alpha) using the Caco-2 human colon carcinoma cell line which exhibits spontaneous epithelial differentiation in vitro. MRC-5 cell culture grown stocks were prepared from: 1. CV Paris, a strain of OC43 recovered from an outbreak of necrotizing enterocolitis in newborns. 2. CV Mb, a neurotropic strain of OC43 which exhibits strict neuronal specificity in murine neuronal cell cultures. 3. CV Rd, a strain of OC43 which grows to a high titer in human rhabdomyosarcoma (RD) cells. Immunofluorescent staining for nucleocapsid antigen and plaque assay in MRC-5 cells was used to detect viral replication. BG-9 (human foreskin) cells challenged with vesicular stomatitis virus were used to detect IFN alpha production by human peripheral blood monocytes (PBMC) stimulated by virus infected Caco-2 cells. Caco-2 cells infected with virus at a multiplicity of infection of 0.5 yielded 10(4.6) and 10(4.4) plaque forming units/ml (pfu/ml) with CV Rd and CV Paris respectively, while CV Mb yielded only 10(3) pfu/ml. Caco-2 cells infected with CV Rd induced 64 IU/ml of IFN alpha in PBMC while these cells infected with CV Paris induced less than 2 IU/ml IFN alpha. In cells infected with CV Mb 4 IU/ml IFN alpha was detected. The results suggest that a lack of IFN alpha induction by CV Paris may be an indicator of its enteropathogenic potential.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical features of Aeromonas enteritis in Hawaii

The incidence and clinical features of enteritis associated with Aeromonas in Honolulu were studied. The stool isolation rate was 2.9% for Aeromonas, the third most common bacterial pathogen in this population. Clinical features of Aeromonas-associated enteritis were compared with clinical features of enteritis without an associated bacterial pathogen. Although there was a trend toward more abdominal pain, tenderness, nausea and prolonged illness in patients with Aeromonas, these differences were not statistically significant. In most cases, Aeromonas enteritis is a self-limited illness, indistinguishable from other causes of diarrhoea seen in our clinic.

Enteric pathogen screening: a multipoint technique with a simple numerical profile

The use of peptone water sugars to screen non-lactose fermenting enteric isolates is expensive and has limited potential for identification. The multipoint system uses seven media from a commercial system containing either single sugars or biochemical substrates. Up to 20 organisms can be tested on each set of plates, the results being used to generate a four figure profile from which a presumptive identity can be obtained. This identity must still be confirmed, but the number of organisms requiring further investigation can be as low as one third of those following use of peptone water sugars. The multipoint system represents a rapid, more accurate and considerably cheaper alternative.

Quinolones and the gastrointestinal tract

A number of studies have evaluated the efficacy of the new fluoroquinolones for therapy of bacterial enteric diseases and for prevention of gram-negative sepsis in granulocytopenic patients. The success of the quinolones in these settings is related to several special features of these agents, including their spectrum of activity and high fecal levels, which are in turn reflected in their effect on the gastrointestinal flora. Other factors that are important, particularly for invasive disease such as typhoid fever and shigellosis, include good intracellular and bowel wall penetration, and lymph node and systemic drug concentrations many times higher than the MICs of the causative organisms. This article reviews the factors that contribute to the changes in fecal flora, and the results of clinical studies in patients with diarrhea, granulocytopenic patients, and patients with selected other infections of, or related to, the gastrointestinal tract.

Species-specific cloned DNA probes for the identification of Campylobacter hyointestinalis

Conventional microbiological methods for isolating and identifying Campylobacter species are laborious, tedious, and subjective. Because of the increasing importance of Campylobacter species in human and animal diseases and the recent emergence of many new species and atypical strains, we are developing chromosomal DNA probes for rapid and simple identification of Campylobacter species, especially those of veterinary importance. We report the cloning and characterization of chromosomal DNA fragments from Campylobacter hyointestinalis, an organism isolated from pigs with proliferative enteritis. To obtain C. hyointestinalis-specific probes, chromosomal DNA fragments from C. hyointestinalis were cloned into plasmid vector pGEM-3Z. Recombinant plasmids were screened for C. hyointestinalis-specific inserts by DNA hybridization, using chromosomal DNA from either C. hyointestinalis or C. fetus which had been 32P labeled. Recombinants which hybridized to C. hyointestinalis, but not C. fetus, DNA were 32P labeled and screened further for sensitivity and specificity. Three probes were identified that were species specific and capable of detecting 10(4) C. hyointestinalis organisms by bacterial spot blotting in 48 h. We anticipate that these probes will be useful for routine species identification and for epidemiological studies.

Yersinia pseudotuberculosis enteritis in four calves

A Yersinia pseudotuberculosis enteritis in four yearling calves is described. This is the first report of this organism causing enteric disease in domestic cattle in North America.

Investigation of zoonotically acquired Campylobacter jejuni enteritis with serotyping and restriction endonuclease DNA analysis

Five strains of Campylobacter jejuni were isolated from asymptomatic coyotes being maintained in a vivarium. According to the results of serotyping with thermostable antigens and of bacterial chromosomal restriction endonuclease analysis, one of the C. jejuni strains isolated from the coyotes was responsible for enteritis in a laboratory animal technician providing husbandry for the laboratory-maintained coyotes.

[The incidence of E. coli O157H7 strains in causing hemorrhagic enterocolitis]

The authors describe the evidencing of the O157H7 E. coli serotype--an enterohaemorrhagic strain of E. coli--for the first time in our country. This germ is incriminated in haemorrhagic enteritis of children and adults, accompanied or not by an uremic haemolytic syndrome. A total of 717 strains were investigated, obtained from cases of haemorrhagic enteritis (283), nonhemorrhagic enteritis (174), food poisoning (27), and a control lot of subjects without signs of enteritis (233). Identification of the strains was done with a screening method (McConkey) with D-sorbitol in place of lactose, and with anti-O157, and anti-H7 sera. The results obtained have indicated a total of 37 positive strains in haemorrhagic enteritis (69.8%), 12 strains in nonhemorrhagic enteritis (22.65%), and 4 strains in food poisoning (7.55%). No strain was isolated from the control group. The percentage of isolated O157H7 E. coli strains in our county is of 7.55% and this contributes to additional knowledge in the definition of the still unknown etiology of diarrhoeic disease in our country.

Development of a murine model to study the pathogenesis of rotavirus infection

A murine model to study enteritis induced by bovine (BRV) and murine rotavirus (MRV) has been developed. The course of infection was determined by clinical symptoms of diarrhea and virus isolation as well as histopathological, immunohistochemical, and electron microscopic methods. Both isolates were able to replicate and produce clinical symptoms in neonatal mice. Rotavirus-free neonates were orally inoculated with MRV or BRV and observed over a 192-hr postinoculation (HPI) period. Following infection with 10(4) PFU of virus, diarrhea and maximal intestinal dysfunction, as measured by xylose absorption, did not occur until beyond 20 hr postinfection even though maximal virus production occurred at 10-15 HPI. Immunohistochemically and by electron microscopy we were able to demonstrate viral antigen and virus particles in the enterocytes of villous tips at 5-8 HPI. The appearance of diarrheal symptoms was dependent on the virus dose and the type of virus isolate inoculated. The disease could be induced with doses as low as 1 x 10(2) PFU/mouse of BRV and 1 x 10(1) PFU/mouse of MRV. On the basis of these results, MRV was found to be more virulent than BRV in this model. The model should prove useful for studies designed to assess rotavirus virulence genes and for vaccine protection studies. This work emphasizes the need for early sample collection for critical evaluation of any vaccine or antiviral agent using this model.

[Antibodies to Campylobacter jejuni in patients with acute enteritis]

In 233 patients with acute diarrhoea in paired sera Campylobacter antibodies classes IgG and IgA were assessed by the ELISA method. As antigen the external membrane protein of the strain Campylobacter jejuni was used. Raised IgG levels (greater than 50 u.) and/or IgA (greater than 80 u.) were found in 15% of all examined patients. A quadruple increase of values in one or both classes was recorded in 12.4% of the patients. The incidence of antibodies against Campylobacter jejuni provides evidence that this infectious agent is frequent in this country. Antibodies class IgA suggest by their dynamics acute contact with the Campylobacter antigen. On the other hand, IgG antibodies are not of major importance in newly diagnosed disease.

Faecal mycobacteria and their relationship to HIV-related enteritis in Lusaka, Zambia

The prevalence of infection with mycobacteria, both typical and atypical, is increasing along with prevalence of infection with HIV. Patients with pulmonary tuberculosis (PTB) and patients with chronic diarrhoea are forming a growing proportion of the patient population in hospitals in central Africa. To investigate the possibility that mycobacteria may be responsible for some of the HIV-related enteropathy seen in Lusaka, we studied 89 patients in four different diagnostic groups, clinically, by Mantoux test and by microscopy and culture of stool specimens for mycobacteria. In the HIV-positive group with chronic diarrhoea (n = 31), two patients were found to have mycobacteria on faecal smear and three were culture positive while of the 15 HIV-negative controls, three were smear positive and three were culture positive. Of the 15 patients with proven PTB, three had positive faecal smears but none were culture positive. In the fourth group of 24 patients with suspected PTB, seven were smear positive and five, culture positive. Only in this last group was there some correlation between smear results and culture results. Although this last finding is difficult to explain, it appears that there is no correlation between the symptom of chronic diarrhoea and the presence of mycobacteria in the stool. We conclude that mycobacteria do not play a significant role in the pathogenesis of HIV-related enteropathy in Lusaka.

[Clinical trial of T-3262 (Tosufloxacin tosilate) on Salmonella enteritis, and fecal drug concentration and change in the fecal microflora in the acute diarrheal patients. Japan Research Committee of T-3262, Research Group for Acute Infectious Enteritis]

For the purpose of evaluation of clinical efficacy, safety and usefulness on Salmonella enteritis, T-3262 (Tosufloxacin tosilate), a newly developed pyridone-carboxylic acid derivative, was administered to a total of 103 patients and carriers. In addition, in vitro antibacterial activity of T-3262 was determined against the clinical isolates, and compared with those of nalidixic acid (NA), pipemidic acid (PPA), enoxacin (ENX), norfloxacin (NFLX) and ofloxacin (OFLX). And when T-3262 was administered to the patients of acute infectious enteritis, fecal drug concentration and their correlation to the changes in the fecal microflora were investigated. The daily dose of 450 mg T-3262 was administered orally three times after meal for 7 days. A total of 63 cases were evaluated (one case of mixed infection caused by Shigella flexneri and Salmonella sp. was included). The clinical efficacy was good in all the enteritis (N = 6). As the bacteriological effect, 60 out of 61 were eradicated, and eradication rate was 98.4%. Adverse effects were observed in four of 102 cases (3.9%), consisting of one with skin rash, one with nausea, headache and stomatitis and two with soft stools. Deteriorations in laboratory findings were seen in 5 of 23 cases (17.4%), consisting of one with elevated GOT, two with elevated GOT and GPT, one with elevated BUN and one with increased eosinophiles count, although they were all slight in degree. MICs of T-3262 which inhibited 90% of the isolates of Salmonella spp. was 0.05 microgram/ml, which was the lowest among the quinolone derivatives tested. The values of the fecal drug concentration of 7 cases of acute infectious enteritis, to which T-3262 administered, were higher than that of MIC90 and recovery rates of T-3262 were distributed from 2.85 to 46.3%. The degrees of changes of the drug concentrations were dependent on individual cases, and did not show the same trend. In addition, changes in the fecal microflora with in 24 hrs after T-3262 administration did not show the same trend.

Adhesion to HeLa cells of Campylobacter jejuni and C. coli outer membrane components

Adhesion of Campylobacter jejuni and C. coli to epithelial cells is thought to be a decisive step in enteritis. In this work, we tried to determine which bacterial components are responsible for this phenomenon. Outer membrane (OM) extracts were prepared from strains of C. jejuni (3 strains) and C. coli (2 strains). These strains had been isolated from stools of febrile patients with diarrhoea and were able to adhere to HeLa cells in culture. After incubation of bacterial OM extracts with HeLa cells in culture, bacterial adherent material was recovered, subjected to electrophoresis and immunoblotted. Bacterial adherent antigens were revealed by a rabbit antiserum raised against whole bacterial cells. Antigenic fractions, ranging from 26 to 30 kDa, were found to preferentially bind to HeLa cells (cell-binding fractions; CBF). These antigens were proteins and were distinct from flagellin and lipopolysaccharide. Bacteria incubated with a rabbit antiserum raised against homologous CBF, were unable to bind to HeLa cells. Moreover, the inhibitory effect decreased when the antiserum was diluted. Under the same conditions, a rabbit antiserum raised against a non-adherent OM fraction of 92 kDa did not prevent bacteria from binding to HeLa cells.

Association of Reoviridae particles in an enteric syndrome of poults observed in turkey flocks during 1988

An enteric syndrome of turkey poults, characterized by enteritis, crop mycosis, intestinal changes (pale, thin-walled ballooning with watery contents), and rickets, occurred during 1988 in 74 turkey flocks from different farms belonging to 9 California turkey growers. The flocks ranged in size from 9,000 to 120,000 birds. Pools of intestine sections from 618 birds, representing 78 field cases, were examined. Histopathological examination of the intestines showed a mild to severe atrophy with a reduced depth of crypts, which was more prominent in the distal part of the small intestine. Viral isolation attempts with primary cell cultures of chicken embryo kidney cells were negative. Examination by electron microscopy of negatively stained intestinal specimens revealed the presence of Reoviridae particles of 58.8 to 80 nm in diameter. Enzyme-linked immunosorbent assay results on the intestinal pools for mammalian and group A avian rotaviruses were negative. A statistically significant relationship was found for the presence of Reoviridae particles in the intestines of 10-21-day-old birds. Of the 7 most common pathological conditions analyzed, 2, rickets and intestinal changes (thin-walled ballooning intestine with watery contents), showed a statistically significant association with the presence of Reoviridae particles.

Early lesions of proliferative enteritis in pigs and hamsters

Gnotobiotic pigs and conventional hamsters were given suspensions of intestinal mucosa from a pig with proliferative hemorrhagic enteropathy and killed 10 or 21 days later. Affected animals had evidence of marked proliferation of immature enterocytes in the intestinal crypts. Numerous Campylobacter-like organisms were in the cytoplasm of enterocytes, and in some instances, bacteria were closely associated with enterocytes. Some intracellular bacteria lying below the microvillous border were within membrane-bound structures. Immunofluorescence and electron immunogold staining with specific antibodies indicated that these organisms were antigenically different from curved bacteria in the crypt lumen of early lesions. This study indicates that the life cycle of the intracellular organisms may involve entry into crypt enterocytes from the intestinal lumen with subsequent intracellular multiplication.

Actin accumulation at sites of bacterial adhesion to tissue culture cells: basis of a new diagnostic test for enteropathogenic and enterohemorrhagic Escherichia coli

Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) adhere to the intestinal mucosa and produce an attaching and effacing (AE) lesion in the brush border microvillous membrane; the AE lesion is characterized by localized destruction of microvilli and intimate attachment of bacteria to the apical enterocyte membrane. A similar lesion is seen when bacteria adhere in vitro to a variety of human tissue culture cell lines. In both cases, dense concentrations of microfilaments are present in the apical cytoplasm beneath attached bacteria. Using a fluorescein-labeled phallotoxin, we have shown that these microfilaments are composed of actin. Cells infected with EPEC and EHEC strains known from electron microscopic studies to produce the AE lesion all exhibited intense spots of fluorescence which corresponded in size and position with each adherent bacterium; cells infected with adherent E. coli strains known not to produce the AE lesion did not produce this striking pattern of fluorescence and were indistinguishable from uninfected control cells. These results indicate that such site-specific concentrations of cytoskeletal actin are characteristic of the AE membrane lesion and can form the basis of a simple, highly sensitive diagnostic test for EPEC and EHEC.

Eumycotic mycetoma caused by Pseudallescheria boydii in a dog

Abdominal eumycotic mycetoma caused by Pseudallescheria boydii was diagnosed in a 3-year-old male Siberian Husky. The dog was examined because of weight loss and signs of depression. Initially, pyrexia was the only clinical finding. Antibiotic and corticosteroid treatment was ineffective. Two weeks later, the dog's appetite had decreased, it had vomited a few times, and the caudal portion of the abdomen was sensitive to palpation. Hematologic and serum biochemical abnormalities consisted of anemia, leukocytosis, hypoglycemia, hypoalbuminemia, hyperglobulinemia, and high alkaline phosphatase activity. One week later, the dog's condition continued to worsen, and testicular swelling was observed. The dog was castrated. Microscopic examination of specimens obtained at surgery revealed pyogranulomatous periorchitis with mycetoma granules. Ketoconazole treatment was initiated and continued until the dog died one month later. Necropsy revealed multifocal duodenal ulcers, with transmural pyogranulomatous enteritis, pancreatitis, and peritonitis. This case is unique because the etiologic agent apparently entered via the intestinal tract rather than by contamination of an external wound.

Antigenic analysis of Campylobacter species and an intracellular Campylobacter-like organism associated with porcine proliferative enteropathies

Whole-cell and outer membrane preparations of Campylobacter mucosalis, C. hyointestinalis, C. jejuni, and C. coli isolated from porcine intestines were compared with preparations of intracellular Campylobacter-like organisms extracted directly from the lesions of pigs with proliferative enteropathy. By gradient polyacrylamide gel electrophoresis, outer membrane and total protein profiles of C. mucosalis, C. hyointestinalis, C. jejuni, and C. coli were significantly different from each other and from those of the Campylobacter-like organisms. Immunoblotting of these preparations with rabbit antisera or monoclonal antibodies prepared against the intracellular Campylobacter-like organisms showed strong reactions only with a 25,000- to 27,000-molecular-weight component of preparations of the intracellular organisms. Antisera to cultivable Campylobacter species isolates did not react with preparations of intracellular organisms. Isoelectric focusing of sonicated preparations showed protein profile differences and an immune-reactive component in the intracellular organisms with a pI of 4.5. This study suggests that the intracellular Campylobacter-like organism associated with proliferative enteropathy may be a novel bacterium with significant antigenic differences from the Campylobacter species previously associated with the disease.

[The occurrence of Treponema in fecal samples from dogs and cats with and without intestinal diseases]

6 (6.9%) of 87 examined dogs without diarrhoea proved to be carriers of Treponema (1x T. hyodysenteriae, 5x T. innocens), whereas in fecal samples from 62 dogs with enteric symptoms no isolation of Treponema succeeded. 5 fecal samples (3.7%) of cats without signs of diarrhoea were found to contain Treponema (1x T. hyodysenteriae, 4x T. innocens), whereas the fecal samples of 31 cats with diarrhoea didn't show any growth of Treponema by cultural investigations. Due to the results of these investigations the conclusion can be drawn that Treponema belong to the usual bacteria of dogs' and cats' intestines and cannot be suspected to cause diarrhoea in these animals primarily.

Genome type analysis of adenoviruses: isolates from one year from the Hannover area

Adenoviruses (AV), isolated from 138 children during the year 1981 in the Hannover area, were studied by DNA restriction analysis with the enzymes BamHI, BglII, BstEII, EcoRI, HindIII, KpnI, and SmaI and compared with the respective prototypes. Varying fragment patterns were depicted and genome types analyzed. Prototype-like strains of AV1 and 5 were not found. Types 2, 5, 1, 3, and 7 showed decreasing genetic variation in that order. Altered restriction sites were physically mapped on the genome; they appeared to be randomly distributed. The high genetic variability of AV2 and 5 is remarkable for this study population, limited in time and space. Clinical and epidemiological data were also presented in relation to serotypes.