SEARCH · PubMed Health

Results for “ENTEROTOXINS”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 469 records · Page 26Linked to original sources

PubMed1986

[Ability of Citrobacter freundii strains isolated in acute intestinal infections to produce LT-enterotoxin].

C. freundii enteropathogenic strains were found to be capable of producing choleroform thermolabile enterotoxin. Thus, in the study of 96 C. freundii strains 38 enterotoxin-producing cultures (39.5%) were revealed by means of the molecular-biological techniques and 29 such cultures (30.0%), by means of the radioimmunoassay (RIA). 100% coincidence was noted in the results of tests for enterotoxigenicity, made by means of RIA or hybridization techniques with the use of the LT-probe containing a cloned fragment with the gene coding the synthesis of LT-enterotoxin in enterotoxigenic Escherichia coli. At the same time only 29 out of 38 Citrobacter strains found to be positive in the hybridization tests, yielded the positive result when tested in RIA for the presence of LT-enterotoxin. This fact should be taken into consideration in the determination of enterotoxin-producing cultures isolated in acute enteric infections, as the method of genetic probing is capable of bringing out the genetic information in bacteria even in the absence of its phenotypical expression.

Acute Disease↗

PubMed1983

Biological activities of enterotoxin from Vibrio cholerae non-01.

The specific antiserum 54(2) prepared in rabbits by combined intraperitoneal and intravenous immunization with the enterotoxin from Vibrio cholerae non-01 was found to neutralize the enterotoxin biologic activity expressed by rabbit skin vascular permeability and hemorrhage factors. The inhibition of biologic activity was also observed when using antiserum to choleragen, but choleragen could not be neutralized by specific serum 54(2). The enterotoxin was also inactivated when heated at 100 degrees C for 10 min, but heating at 56 degrees C for 30 min had no influence on its biologic activity. The enterotoxin from Vibrio cholerae non-01 was found to elevate concentration levels of cAMP in the epithelial cells of the rabbit intestine and this elevation was comparable with that produced by the filtrate of Vibrio cholerae 569 B culture. The culture filtrate from Vibrio cholerae non-01 exhibited a similar activity. The Vibrio cholerae non-01 enterotoxin as well as the original culture filtrate were found to be cytotoxic for Vero cells.

Adenylyl Cyclases↗

PubMed1983

Use of enzyme linked immunosorbent assay (ELISA) in the quantitation of Clostridium perfringens type A enterotoxin and antienterotoxin antibodies.

ELISA procedure for quantitation of enterotoxin of Clostridium perfringens type A was worked out. It was possible to detect as little as 0.0022 microgramme of enterotoxin. When applied to quantitate the enterotoxin in laboratory contaminated faeces and cooked minced beef, ELISA detected as little as 0.024 microgramme of enterotoxin. ELISA procedure for determination of titre of antibodies to enterotoxin was also developed using hyperimmunised rabbit and sheep sera. It was possible to use this procedure in sero-survey.

Animals↗

PubMed1983

[Modification of a method of passive immune hemolysis on a solid medium for detecting the production of thermolabile enterotoxins by Vibrio cholerae and Escherichia coli strains].

A modification of the passive immune hemolysis method for the determination of the production of thermolabile enterotoxins by V. cholerae and E. coli is proposed. This modification permits the use of solid culture media. Experiments with cholera enterotoxin have demonstrated that the sensitivity of the modified method is 8-10 times higher than that of the Elek method. Similar results have been obtained with the use of the proposed method in the study of the capacity of different V. cholerae and E. coli strains for producing enterotoxins. The results obtained with the use of this method have been found to correlate with those obtained by means of the skin test and passive immune hemolysis in a liquid medium. We have used the modified method in the study of the production of thermolabile enterotoxin in transconjugants obtained by the hybridization of E. coli strain GA 107 carrying plasmid pCG86 which determines the synthesis of thermolabile and thermostable enterotoxins and E. coli strain K12 C600 R. The results obtained in the study of toxin formation in 99 transconjugants, carried out with the use of the proposed method, the skin test and passive immune hemolysis, have been shown to coincide.

Animals↗

PubMed1983

[Demonstration of enterotoxin in Staphylococcus aureus cultures by the ELISA test and the microslide test].

340 S. aureus strains, isolated either from routine food test samples, or from food leftovers, from healthy or sick persons in cases of suspected food poisoning in various places of the Federal Republic of Germany, were tested for enterotoxin production. The enterotoxin types A, B and C (SEA, SEB and SEC) were determined both by the ELISA and the microslide test (MS-test), the enterotoxin types D and E by the MS-test only. Comparison of the two test methods clearly shows that the ELISA technique is superior to the MS method: The sensitivity of the ELISA was at 2.5 ng, whereas that of the MS-test was limited to approximately 1 microgram. The ELISA revealed 6.2% more of the strains as enterotoxin producers, and reproducibility of the test results was also better with the ELISA than with the MS-test. Furthermore, the ELISA is far more efficient, consuming less test reagents, and with a capacity for testing more strains in a shorter time procedure. The incidence rate of the various enterotoxin types, referred to one representative strain each per outbreak of food poisoning or group of persons investigated, is as follows: 45.3% SEA, 17.2% SEB, 23.4% SEC. The incidence rate of SED, SEE or SE-type combinations was less than 5%. In sick persons, SEA- and SEC-producing strains occurred within the same range, i.e. 34.8% and 30.4% respectively. SEA-producing S. aureus strains had the highest frequency in food samples (61.5%) and in healthy individuals (53.6%).

Enterotoxins↗

PubMed1983

Production, partial purification and characterization of Salmonella heat-labile enterotoxin.

A heat-labile enterotoxin possessing both diarrheogenic and skin permeability reactions has been isolated from Salmonella weltevreden. The enterotoxin was mainly located intracellularly in the cell wall fraction. By chemical and physical techniques such as EDTA treatment of cell walls, fractional ammonium sulphate precipitation and continuous sucrose gradient centrifugation of cell sap (cell free extract) and gel filtration chromatography of culture supernatant, the enterotoxin has been partially purified. The enterotoxin resembled the heat labile enterotoxin of E. coli and the cholera toxin with respect to its thermal stability; however, it was different in its sensitivity to acidic and alkaline pH. Its activity was lost completely on treatment with Pronase and trypsin. The toxin appears to be of a high molecular weight and its enterotoxic activity is associated with a protein moiety.

Bacterial Toxins↗

PubMed1982

Biologic activity of cell-associated staphylococcal enterotoxin A.

Cell associated staphylococcal enterotoxin A, released by lysostaphin treatment of Staphylococcus aureus cells, was found to be biologically active in cynomolgus monkeys. The activity was comparable to that of extracellular enterotoxin A; six of six monkeys vomited within 5 h in response to extracellular enterotoxin and four of six also vomited in response to the same serologic level (4.8 micrograms per monkey) of cell-associated enterotoxin. Feeding S. aureus cells containing cell-associated enterotoxin A to cynomolgus monkeys resulted in emesis in three of five monkeys within 3 h. This suggests that consumption of S. aureus cells could lead to staphylococcal intoxication.

Animals↗

PubMed1981

Enterotoxin production by Staphylococcus aureus related to the origin of the strains.

The production of enterotoxins by strains of Staphylococcus aureus of human and animal origin seems to be common. 104 out of 170 strains (61%) produced one or more of the A, B, and C enterotoxins. Strains from cow and milk often produced enterotoxin C, and enterotoxin A producing strains were mainly isolated from dogs. Human food poisoning seemed in our material to be induced by enterotoxin A producing strains.

Animals↗

PubMed1980

Studies on the pathogenicity of Yersinia enterocolitica and Y. enterocolitica-like bacteria. 1. Enterotoxin production at 22 degrees C and 37 degrees C by environmental and human isolates from Scandinavia.

Altogether, 412 strains of Yersinia enterocolitica and Y. enterocolitica-like bacteria from environmental and human sources were examined for their ability to produce enterotoxin at 22 degrees C and 37 degrees C using the infant mouse assay. A total of 73 strains were positive at 22 degrees C, only. Another 28 strains were positive both at 22 degrees C and 37 degrees C. Of these 28 strains, 26 were sucrose and aesculin non-fermenting and all were Voges-Proskauer negative. All of these strains were isolated from non-human sources. All of 13 strains belonging to O-serogroup 28 produced enterotoxin at 37 degrees C. The results indicate that enterotoxin production at 22 degrees C is widespread in Y. enterocolitica with the highest prevalence among human clinical isolates. Enterotoxin production at both 22 degrees C and 37 degrees C seems to be common in Y. kristensenii (sucrose non-fermentors). Enterotoxin production is apparently rare in Y. frederiksenii (rhamnose fermentors) and in Y. intermedia (rhamnose and melibiose fermentors).

Animals↗

PubMed1976

[Pathology and pathogenesis of coli dysentery and coli diarrhea in suckling piglets. 2. Studies on the experimental induction of disease through the intragastric administration of coli-enterotoxin].

Fractionated intragastric application of a crude enterotoxin of Escherichia coli O 149:K91 (B) K88 (L) was part of experimental intoxication of 88 nursed piglets, aged between one and three days. The experiment was based on culture filtrate supernatant which had produced positive enterotoxic effect in an intestinal ligature test of swine and rabbit. The results were compared with 50 controls, piglets of the same age with intragastric administration of physiological salt solution. The experiment gave pronounced aquaeous diarrhoea (100 per cent) accoumpanied by exsiccosis, weight loss, rough hair, greyish discoloration of the skin, and other manifestations. The mortality was nine per cent. The clinical and pathomorphological picture of the enterotoxin syndrome was in close agreement with spontaneous coli-bacillosis of nursed piglets. Enterotoxin-caused diarrhoea occurred, with the gastro-intestinal mucous membrane remaining morphologically intact. This intoxication method has proved to be a safe model for experimental induction of coli-bacillosis, and it is likely to be suitable for vaccine testing. It can be used, as well, as a simple qualitative enterotoxin test. Additional issues relating to the pathology and pathogenesis of the coli-enterotoxin syndrome of piglets are discussed.

Animals↗

PubMed1976

[Experimental studies on the pathogenesis of coli enterotoxemia in swine. 3. Effect of coli enterotoxin in weaned piglets following intragastric administration].

The following results were obtained from experiments with 23 clinically intact weaned piglets, aged between five and six weeks (18 animals) or eight weeks (five animals), which had received three intragastric applications of crude enterotoxin (culture filtrate supernatant of Escherichia coli O149:K91(B)K88(L):. 1. Twelve animals (52 per cent) responded to enterotoxin application by temporary outbreaks of diarrhoea (1-8.5 hours) following differentiated latencies (2.5-10 hours). No diarrhoea was recorded from eleven piglets (48%) which had received the same doses of enterotoxin. 2. No signs of a systemic disease were clinically recordable after enterotoxin administration from 22 (96%) animals, no matter whether diarrhoea had developed or not. Respiration, temperature, heart rate, and haematological values were unchanged. Feed and water intake were normal. No exsicosis was observed. All animals exhibited lively behaviours and activity. The conclusion drawn regarding the pathogenesis of the gastrointestinal form of coli-enterotoxaemia, with reference to the authors' own earlier findings, is that in this disease parenteral endotoxin effects (following endotoxin resorption) seem to coincide with enteral enterotoxin effects.

Animals↗

PubMed1976

Collaborative study of the serological identification of staphylococcal enterotoxins by the microslide gel double diffusion test.

A collaborative study was conducted, using the microslide gel double diffusion test for enterotoxin detection by determining the staphylococcal enterotoxigenicity of 7 strains of Staphylococcus aureus. Two strains produced staphylococcal enterotoxin A (SEA), 2 strains produced staphylococcal enterotoxin B (SEB), one strain produced both SEA and SEB, and 2 strains produced neither SEA nor SEB. To ascertain the effectiveness of this method for the detection of enterotoxins, strains of enterotoxigenic staphylococci which produced small or relatively large amounts of toxin were used in the study. The cultures were grown on semi-solid brain-heart infusion agar and the culture fluids were assayed serologically for SEA and SEB. The qualitative results of this study by 16 collaborators indicated that this technique, in general, demonstrated a high degree of specificity as well as simplicity and reproducibility in the identification of the enterotoxins. Of the 16 participating laboratories, 14 reported the correct diagnoses for the 7 staphylococcal strains studied and 2 laboratories determined 6 of the 7 strains correctly. Based on these results, this method has been adopted as official first action.

Culture Media↗

PubMed1993

[The occurrence and significance of enterotoxin-producing Clostridium perfringens strains in the intestinal tract of horses].

100 faecal samples from clinically healthy horses of different age groups and feeding habits, 50 samples of faeces from horses suffering from enteropathy accompanied by diarrhoea and small and/or large intestine from 25 horses that had died after an intestinal disease were examined for the presence of Clostridium (Cl.) perfringens. The frequency with which Cl. perfringens was detected was 22% in clinically healthy horses, 32% in horses with diarrhoea and 52% in the dead horses. In two faecal samples from the horses with diarrhoea the microbial count of Cl. perfringens was ca. 10(6) cfu/g faeces. The occurrence of Cl. perfringens in clinically healthy horses was not influenced by age. In animals fed exclusively on grass silage Cl. perfringens was found more frequently. The enterotoxin of Cl. perfringens was identified in one of 36 faecal samples from horses with diarrhoea. 54 Cl. perfringens strains isolated from material examined were studied for their ability to sporulate and to produce enterotoxin. 98% of the strains formed spores. Enterotoxin production was negative in all cases. Experimental investigations with enterotoxin producing Cl. perfringens strains on four ponies did not show any signs of a possible durable colonization of the intestinal tract by this organism. The results of these investigations do not suggest any pathogenic relevance of enterotoxin producing Cl. perfringens strains to the development of enteropathy in horses.

Animals↗

PubMed1994

Determination of staphylococcal enterotoxins in milk and milk products by three methods.

For food evaluation, the determination of the number of Staphylococcus aureus colonies is insufficient in the view of present scientific knowledge. The results, advantages and disadvantages of diagnostic methods are demonstrated on an example of three methods of detection of staphylococcal enterotoxins in milk and milk products. 133 strains were investigated with the method of biotyping of Staphylococcus aureus strains. Four of their strains were included in biotype A, seven strains of S. aureus were not included in any biotype and the other strains belonged in biotypes C and E. This method can be used as an auxiliary method for evaluation of foods containing S. aureus bacteria. The agar-gel precipitation method of enterotoxin detection in isolated strains of Staphylococcus aureus has just restricted valiability. When examining 96 strains of S. aureus with this method, strains which were producing staphylococcal enterotoxins were isolated 17 times. The main disadvantage of this method is a fact that the result concerning the isolated strains need not be identical with the result of enterotoxin detection in food. Direct assays of staphylococcal enterotoxins in milk and milk products using an enzymoimmunological method (ELISA test) seem to be most promising, mainly due to their high sensitivity (0.0001-0.001 micrograms.ml-1) and other advantages.

Animals↗

PubMedDate not supplied

Immunoenzymatic detection of staphylococcal enterotoxins: international interlaboratory study.

An international interlaboratory study was performed by 13 laboratories to validate a commercially available, rapid enzyme immunoassay for detection of staphylococcal enterotoxins A, B, C, D, and E in foods. The 5 enterotoxin serotypes were detected at a level of 0.5 ng/g in mushrooms and ravioli, 0.8 ng/g in meat, 1 ng/mL in milk, and 1.5 ng/g in raw milk cheese when these foods were artificially contaminated with enterotoxin A. Enterotoxins A, B, C, D, or E were also detected in culture supernatants with no protein A interference when normal rabbit serum was used. This method was validated by the French Normalization Agency for the identification of staphylococcal enterotoxins in foods and culture fluids.

Antibody Specificity↗

PubMed2004

New insights into the cytotoxic mechanisms of Clostridium perfringens enterotoxin.

Clostridium perfringens type A isolates producing the 35 kDa enterotoxin (CPE) are an important cause of food poisoning, human non-foodborne gastrointestinal (GI) disease, and some veterinary GI diseases. Studies using CPE knock-out mutants confirmed the importance of enterotoxin expression for the enteric virulence of CPE-positive type A isolates. CPE action involves formation of a series of complexes in mammalian plasma membranes. One such CPE-containing complex (of approximately 155 kDa) is important for the induction of plasma membrane permeability alterations, which are responsible for killing enterotoxin-treated mammalian cells. Those membrane permeability changes damage the epithelium, allowing the enterotoxin to interact with the tight junction (TJ) protein occludin. CPE:occludin interactions result in formation of an approximately 200 kDa CPE complex and internalization of occludin into the cytoplasm. That removal of occludin (and possibly other proteins) damages TJs and disrupts the normal paracellular permeability barrier of the intestinal epithelium, which may contribute to CPE-induced diarrhea. Recent studies demonstrated that low CPE doses kill mammalian cells by inducing a classic apoptotic pathway involving mitochondrial membrane depolarization, cytochrome C release, and caspase 3/7 activation. In contrast, high enterotoxin doses induce oncosis, a proinflammatory event. Thus, inflammation may also contribute to the GI symptoms of patients whose intestines contain high CPE levels. In summary, CPE is a unique, multifunctional toxin with cytotoxic, TJ-damaging, and (probably) proinflammatory activities.

Journal Article↗

PubMed1981

Production of cholera-like enterotoxin by a Vibrio cholerae non-O1 strain isolated from the environment.

Vibrio cholerae non-O1 strain E8498, isolated in 1978 from fresh water in Louisiana, produced a vascular permeability factor when cultured in shallow resting cultures of Casamino Acids-yeast extract-glucose medium for 24 h at 30 degrees C. Undiluted resting culture filtrates contained heat-labile permeability factor activity which was only partially neutralized by cholera antitoxin and GM1 ganglioside. Supernatants concentrated with PM-10 membranes caused hemorrhage and necrosis in rabbits within 1 h after intracutaneous injection, whereas appropriate dilutions of both filtrates and concentrates demonstrated delayed permeability factor activity, without hemorrhage or necrosis, which was indistinguishable in appearance from that caused by purified cholera enterotoxin produced by V. cholerae O1 Inaba strain 569B. Crude E8498 filtrates contained the biological equivalent of about 5 ng/ml of purified enterotoxin. Permeability factor activity in the fraction obtained by 20 to 50% saturation of filtrate concentrate with ammonium sulfate could be completely neutralized by reference standard cholera antitoxin prepared against purified 569 B enterotoxin. Hemorrhagic activity was unaffected by cholera antitoxin. A 5,000-fold concentrate of the culture supernatant yielded a line of identity with purified cholera enterotoxin in an agar gel double-diffusion test against cholera antitoxin purified by affinity column chromatography with BrCN-activated Sepharose 4B-linked purified cholera enterotoxin as the adsorbent. These findings indicate that V. cholerae non-O1 E8498 produces a permeability factor which is immunologically and biologically indistinguishable from that produced by a strain of V. cholerae O1 classical biotype.

Antitoxins↗

PubMed2005

Enterotoxin-based mucosal adjuvants alter antigen trafficking and induce inflammatory responses in the nasal tract.

The safety of nasal vaccines containing enterotoxin-based mucosal adjuvants has not been studied in detail. Previous studies have indicated that native cholera toxin (nCT) can alter antigen trafficking when applied nasally. In this study, we determined the enterotoxin-based variables that alter antigen trafficking. To measure the influence of enterotoxin-based mucosal adjuvants on antigen trafficking in the nasal tract, native and mutant enterotoxins were coadministered with radiolabeled tetanus toxoid (TT). The nCT and heat-labile enterotoxin type 1 (LTh-1) redirected TT into the olfactory neuroepithelium (ON/E). Antigen redirection occurred mainly across the nasal epithelium without subsequent transport along olfactory neurons into the olfactory bulbs (OB). Thus, no significant accumulation of the vaccine antigen TT was observed in the OB when coadministered with nCT. In contrast, neither mutant CT nor mutant LTh-1, which lack ADP-ribosyltransferase activity, redirected TT antigen into the ON/E. Thus, ADP-ribosyltransferase activity was essential for antigen trafficking across the olfactory epithelium. Accumulation of TT in the ON/E was also due to B-subunit binding to GM1 gangliosides, as was demonstrated (i) by redirection of TT by LTh-1 in a dose-dependent manner, (ii) by ganglioside inhibition of the antigen redirection by LTh-1 and nCT, and (iii) by the use of LT-IIb, a toxin that binds to gangliosides other than GM1. Redirection of TT into the ON/E coincided with elevated production of interleukin 6 (IL-6) but not IL-1beta or tumor necrosis factor alpha in the nasal mucosa. Thus, redirection of TT is dependent on ADP-ribosyltransferase activity and GM1 binding and is associated with production of the inflammatory cytokine IL-6.

ADP Ribose Transferases↗