Assessment of two commercial agglutination kits for detecting Escherichia coli heat-labile enterotoxin

1991 ◽  
Vol 37 (11) ◽  
pp. 877-880 ◽  
Author(s):  
J. Speirs ◽  
S. Stavric ◽  
B. Buchanan
Keyword(s):  
Escherichia Coli ◽  
Cell Culture ◽  
Key Words ◽  
Agglutination Test ◽  
Enzyme Linked Immunosorbent Assay ◽  
Gm1 Ganglioside ◽  
Heat Labile ◽  
Toxigenic Strains ◽  
Good Substitute ◽  
Key Words Escherichia Coli

Two commercial agglutination kits, a reserved passive agglutination test (VET-RPLA) and a staphylococcal coagglutination test (Phadebact ETEC-LT Test), were compared with two cell culture assays (Y-1 and Vero) and GM1 ganglioside enzyme-linked immunosorbent assay (GM1-ELISA) for sensitivity in detecting Escherichia coli heat-labile enterotoxin (LT). Of 48 toxigenic strains, 23 were positive by all assays. One strain was negative only by the Phadebact test. Four strains, all LT-II producers, were positive by cell culture only. For LT-I detection, the Phadebact test was the least sensitive but was simple and rapid; VET-RPLA was simple, sensitive, and a good substitute for cell culture or GM1-ELISA. Key words: Escherichia coli, heat-labile enterotoxin, agglutination kits.

scholarly journals Identification of Toxin A-Negative, Toxin B-Positive Clostridium difficile by PCR

1998 ◽  
Vol 36 (8) ◽  
pp. 2178-2182 ◽  
Author(s):  
Haru Kato ◽  
Naoki Kato ◽  
Kunitomo Watanabe ◽  
Naoichi Iwai ◽  
Haruhi Nakamura ◽  
...  
Keyword(s):  
Cell Culture ◽  
Clostridium Difficile ◽  
Pcr Amplification ◽  
Enzyme Linked Immunosorbent Assay ◽  
Pcr Assay ◽  
Toxin A ◽  
Toxin B ◽  
Cell Monolayers ◽  
Toxigenic Strains ◽  
Cell Culture Assay

Toxigenic strains of Clostridium difficile have been reported to produce both toxins A and B nearly always, and nontoxigenic strains have been reported to produce neither of these toxins. Recent studies indicate that it is not always true. We established a PCR assay to differentiate toxin A-negative, toxin B-positive (toxin A−, toxin B+) strains from both toxin-positive (toxin A+, toxin B+) strains and both toxin-negative (toxin A−, toxin B−) strains as an alternative to cell culture assay and enzyme-linked immunosorbent assay (ELISA). By using the PCR primer set NK11 and NK9 derived from the repeating sequences of the toxin A gene, a shorter segment (ca. 700 bp) was amplified from toxin A−, toxin B+ strains compared to the size of the segment amplified from toxin A+, toxin B+ strains (ca. 1,200 bp), and no product was amplified from toxin A−, toxin B− strains. We examined a total of 421 C. difficile isolates by PCR. Of these, 48 strains showed a shorter segment by the PCR, were negative by ELISAs for the detection of toxin A, and were positive by cell culture assay. Although the cytotoxin produced by the toxin A−, toxin B+ strains was neutralized by anti-toxin B serum, the appearance of the cytotoxic effects on Vero cell monolayers was distinguishable from that of toxin A+, toxin B+ strains. By immunoblotting, the 44 toxin A−, toxin B+ strains were typed to serogroup F and the remaining four strains were serogroup X. Pulsed-field gel electrophoresis separated the 48 strains into 19 types. The PCR assay for the detection of the repeating sequences combined with PCR amplification of the nonrepeating sequences of either the toxin A or the toxin B gene is indicated to be useful for differentiating toxin A−, toxin B+ strains from toxin A+, toxin B+ and toxin A−, toxin B− strains and will contribute to elucidation of the precise role of toxin A−, toxin B+ strains in intestinal diseases.

Microtiter ganglioside enzyme-linked immunosorbent assay for vibrio and Escherichia coli heat-labile enterotoxins and antitoxin.

1980 ◽  
Vol 11 (1) ◽  
pp. 35-40 ◽  
Author(s):  
D A Sack ◽  
S Huda ◽  
P K Neogi ◽  
R R Daniel ◽  
W M Spira
Keyword(s):  
Escherichia Coli ◽  
Immunosorbent Assay ◽  
Enzyme Linked Immunosorbent Assay ◽  
Heat Labile

scholarly journals Mutants of Type II Heat-Labile Enterotoxin LT-IIa with Altered Ganglioside-Binding Activities and Diminished Toxicity Are Potent Mucosal Adjuvants

2006 ◽  
Vol 75 (2) ◽  
pp. 621-633 ◽  
Author(s):  
Hesham F. Nawar ◽  
Sergio Arce ◽  
Michael W. Russell ◽  
Terry D. Connell
Keyword(s):  
Escherichia Coli ◽  
Immune Responses ◽  
Binding Activity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Type I ◽  
Type Ii ◽  
Heat Labile ◽  
Enhanced Expression ◽  
Adhesin Protein ◽  
And Function

ABSTRACT The structure and function LT-IIa, a type II heat-labile enterotoxin of Escherichia coli, are closely related to the structures and functions of cholera toxin and LT-I, the type I heat-labile enterotoxins of Vibrio cholerae and enterotoxigenic Escherichia coli, respectively. While LT-IIa is a potent systemic and mucosal adjuvant, recent studies demonstrated that mutant LT-IIa(T34I), which exhibits no detectable binding activity as determined by an enzyme-linked immunosorbent assay, with gangliosides GD1b, GD1a, and GM1 is a very poor adjuvant. To evaluate whether other mutant LT-IIa enterotoxins that also exhibit diminished ganglioside-binding activities have greater adjuvant activities, BALB/c mice were immunized by the intranasal route with the surface adhesin protein AgI/II of Streptococcus mutans alone or in combination with LT-IIa, LT-IIa(T14S), LT-IIa(T14I), or LT-IIa(T14D). All three mutant enterotoxins potentiated strong mucosal immune responses that were equivalent to the response promulgated by wt LT-IIa. All three mutant enterotoxins augmented the systemic immune responses that correlated with their ganglioside-binding activities. Only LT-IIa and LT-IIa(T14S), however, enhanced expression of major histocompatibility complex class II and the costimulatory molecules CD40, CD80, and CD86 on splenic dendritic cells. LT-IIa(T14I) and LT-IIa(T14D) had extremely diminished toxicities in a mouse Y1 adrenal cell bioassay and reduced abilities to induce the accumulation of intracellular cyclic AMP in a macrophage cell line.

The effect of fasting and diet on fecal shedding of Escherichia coli O157:H7 by cattle

2000 ◽  
Vol 80 (4) ◽  
pp. 741-744 ◽  
Author(s):  
S. J. Buchko ◽  
R. A. Holley ◽  
W. O. Olson ◽  
V. P. J. Gannon ◽  
D. M. Veira
Keyword(s):  
Escherichia Coli ◽  
Key Words ◽  
Escherichia Coli O157 ◽  
Fecal Shedding ◽  
E Coli ◽  
Feed Withdrawal ◽  
Alfalfa Silage ◽  
Key Words Escherichia Coli

Cattle naturally infected with Escherichia coli O157:H7 were used to assess the effects of diet and feed withdrawal on the fecal shedding of E. coli O157:H7. Animals were fed an 80% concentrate diet (80% barley and 20% alfalfa silage), fasted for 48 h, fed a 100% forage diet (alfalfa silage), fasted for 48 h, and subsequently re-fed 100% forage (alfalfa silage). There were no differences in the numbers of animals positive for the shedding of E. coli O157:H7 when fed an 80% barley diet or an all-forage diet (P > 0.05) or during the fasting periods following each diet (P > 0.05). Upon re-feeding an all-forage diet following a 48-h fast, animals positive for E. coli O157:H7 shedding increased (P < 0.05), with 42.5% of the animals shedding the pathogen after 5 d. Re-feeding 100% forage following fasting appeared to have increased the number of animals shedding E. coli O157:H7 in their feces, which may have been influenced by diet in addition to fasting. Key words: Escherichia coli O157:H7, fasting, diet, cattle, fecal shedding

Detection of Escherichia coli cytotoxins by enzyme-linked immunosorbent assays

1991 ◽  
Vol 37 (8) ◽  
pp. 650-653 ◽  
Author(s):  
Joan I. Speirs ◽  
Mumtaz Akhtar
Keyword(s):  
Escherichia Coli ◽  
Monoclonal Antibody ◽  
Monoclonal Antibodies ◽  
Vero Cell ◽  
Key Words ◽  
E Coli ◽  
Treated Cell ◽  
Cell Extracts ◽  
Immunosorbent Assays ◽  
Key Words Escherichia Coli

Sandwich enzyme-linked immunosorbent assays (ELISAs) were developed to detect Escherichia coli cytotoxins. Wells were coated with monoclonal antibodies from hybridomas 13C4 and (or) 11E10, and biotin conjugates of these antibodies were used for detecting verotoxin 1 and Shiga-like toxin II, respectively. Sensitivities were about 100 and 200 cytotoxic doses, respectively. Verotoxin 2 was detected by ELISA with monoclonal antibody 11E10, but at a sensitivity of only about 4000 cytotoxic doses. ELISA results of polymyxin-treated cell extracts from cultures of 67 E. coli strains were in agreement with Vero cell assay as regards the presence and type of toxin. Key words: Escherichia coli, cytotoxin, ELISA.

scholarly journals Escherichia coliin gastroenteritis of children in Auckland, New Zealand

1981 ◽  
Vol 87 (3) ◽  
pp. 413-419 ◽  
Author(s):  
P. N. Goldwater ◽  
K. A. Bettelheim ◽  
R. B. Ellis-Pegler
Keyword(s):  
Escherichia Coli ◽  
New Zealand ◽  
Causative Role ◽  
E Coli ◽  
Heat Stable ◽  
Heat Labile ◽  
Toxigenic Strains

SummaryA study of stoolEscherichia coliin 60 children with gastroenteritis and 18 control children was carried out in Auckland, New Zealand in 1977. Toxigenic strains, heat labile and heat stable, predominated in the stools of only three children, all of whom had concomitant rotavirus. Classical enteropathogenicE. coli(EPEC) were found in patients and controls. Only one patient had many EPEC in the stool (086. H2), they were variably toxigenic and rotavirus was also present. No toxigenic serotype was isolated. Two potential pathogens were sometimes found. Overall there was no evidence for a substantial causative role for disease producingE. coliin these children.

scholarly journals Expression of Escherichia coli heat-labile enterotoxin B subunit in transgenic tomato (Solanum lycopersicum L.) fruit

2014 ◽  
Vol 50 (No. 1) ◽  
pp. 26-31 ◽  
Author(s):  
N.H. Loc ◽  
D.T. Long ◽  
T.-G. Kim ◽  
M.-S. Yang
Keyword(s):  
Escherichia Coli ◽  
Solanum Lycopersicum ◽  
Blot Hybridization ◽  
Transgenic Tomato ◽  
Enzyme Linked Immunosorbent Assay ◽  
Potential Candidate ◽  
B Subunit ◽  
Solanum Lycopersicum L ◽  
Heat Labile ◽  
Enterotoxin B

We report a feasibility study for expressing the LTB protein (Escherichia coli heat-labile enterotoxin B subunit) via Agrobacterium-mediated transformation of tomato (Solanum lycopersicum L.). We produced five regenerated plants obtained on the selection medium supplemented with an antibiotic. Stable integrations of the LTB&nbsp;gene into the genome of these plants were confirmed by Southern blot hybridization. Western blot analysis showed that only two of the five T<sub>0 </sub>transgenic tomato plants expressed the pentameric LTB protein in the fruits. An enzyme-linked immunosorbent assay indicated that these two plants synthesized the LTB protein bound specifically to GM1 ganglioside, suggesting that the LTB subunits formed active pentamers. The LTB protein produced in tomatoes can be a potential candidate for inexpensive, safe, and effective plant-based vaccines.

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