Detection of Escherichia coli enterotoxins in stools

Merson, Michael H.; Yolken, R H; Sack, R. Bradley; Froehlich, J L; Greenberg, Harry B.; Huq, I.; Re, Black

doi:10.1128/iai.29.1.108-113.1980

Cited by 33 publications

(7 citation statements)

References 26 publications

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“…The standard assays for enterotoxin are overdue for improvements. Although several investigators have shown other methods to be feasible (10,12,14,16,17), the YAC assay remains the standard assay. Pooling of culture supernatants derived from isolated E. coli has been the standard method for screening samples for enterotoxin production.…”

Section: Discussionmentioning

confidence: 99%

Comparison of methods to detect Escherichia coli heat-labile enterotoxin in stool and cell-free culture supernatants

Morgan¹,

DuPont²,

Wood³

et al. 1983

J Clin Microbiol

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We compared the standard Y-1 adrenal cell (YAC) assay for heat-labile enterotoxin (LT) with newer rapid and economical immunological methods of detection. Stool samples were collected from 164 acutely ill American students in Guadalajara, Mexico. Supernatants were prepared from each stool. Stools were cultured for Escherichia coli by standard techniques. Individual E. coli-like colonies were examined for LT production by the Biken assay. Culture supernatants and stool supernatants were assayed for the presence of LT by the YAC assay, counterimmunoelectrophoresis, and enzyme-linked immunosorbent assay (ELISA). Standard YAC assays of culture supernatants revealed that 40 of the 164 specimens (24%) were LT positive. Counterimmunoelectrophoresis detected 60% and ELISA detected 65% of the 40 known positives when culture supernatants were used. The Biken assay detected 35% of the 40 known positives. With stool supernatants, the YAC assay detected only 18% of the known positives, counterimmunoelectrophoresis detected 60%, and ELISA detected 90%. In addition, ELISA detected 13 LT-positive stool supernatants not detected by the YAC assay of culture supernatants. The ELISA in which stool supernatants are used may be a useful method to detect LT.

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Section: Discussionmentioning

confidence: 99%

Comparison of methods to detect Escherichia coli heat-labile enterotoxin in stool and cell-free culture supernatants

Morgan¹,

DuPont²,

Wood³

et al. 1983

J Clin Microbiol

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“…When the suckling mouse assay was used to detect ST. directly in stools, ST was found in only 36% of the cases from which ST-producing E. coli strains were isolated (17). With a more sensitive assay, the percentage of ST detection will probably increase substantially.…”

Section: Discussionmentioning

confidence: 99%

Development of a radioimmunoassay for Escherichia coli heat-stable enterotoxin: comparison with the suckling mouse bioassay

Giannella¹,

Drake²,

Luttrell³

1981

Infect Immun

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Escherichia coli strains which produce heat-stable enterotoxin (ST) are usually identified by demonstrating the production of ST. At present, ST can be detected only by bioassay methods. Recently, we purified E. coli ST, which enabled us to develop a radioimmunoassay for ST. Radioiodination of ST was performed by the lactoperoxidase method, which resulted in a high specific activity and retained the biological activity of St. Anti-ST antisera were raised in goats by injecting the goats with pure ST coupled to bovine immunoglobin G. Antibody titers ranged from 1:8,000 to 1:40,000. Using these reagents, we examined assay conditions thoroughly and found that a 14- to 18-h incubation at 4 degrees C in sodium acetate buffer with an ionic strength of 120 mM (pH 6.2) gave maximal sensitivity and reproducibility. Free ST was separated from antibody-bound ST by dextran-coated charcoal. This radioimmunoassay accurately and reproducibly measured ST in the range from 50 to 500 pg of ST per tube and could quantitate ST accurately in complex bacteriological media. This assay was specific for STa, measured human and porcine STa equally well, and did not cross-react with STb, with several other enterotoxins, or with various gastrointestinal peptides. Intact disulfide bridges in the ST molecule were required for immunoreactive activity.

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“…Examples of toxins that have been detected directly in stools from infected patients include Clostridium difficile toxin A (reviewed in reference 271), Shiga toxin (324), CT (reviewed in reference 383), and the heat-labile (LT-I) and heat-stable (STa) toxins from enterotoxigenic E. coli (ETEC) (365). How-ever, failure to detect toxins in stools may be due to the insensitivity of the detection assay, the toxin-binding effects of free gangliosides present in mucin found in stools, proteolytic degradation of the toxin in the intestinal tract, or other reasons.…”

Section: Introductionmentioning

confidence: 99%

Enteric bacterial toxins: mechanisms of action and linkage to intestinal secretion.

Sears¹,

Kaper²

1996

Microbiological Reviews

317

145

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Detection of Escherichia coli enterotoxins in stools

Cited by 33 publications

References 26 publications

Comparison of methods to detect Escherichia coli heat-labile enterotoxin in stool and cell-free culture supernatants

Comparison of methods to detect Escherichia coli heat-labile enterotoxin in stool and cell-free culture supernatants

Development of a radioimmunoassay for Escherichia coli heat-stable enterotoxin: comparison with the suckling mouse bioassay

Enteric bacterial toxins: mechanisms of action and linkage to intestinal secretion.

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