A two-year survey of the incidence of heat-labile enterotoxin-producingEscherichia coliand other enteric pathogens in travellers returning to the Sheffield area
15
Citation
36
Reference
10
Related Paper
Abstract:
A case-controlled study of the incidence of heat-labile enterotoxin-producing Escherichia coli (LT+ETEC) and other enteric pathogens in travellers returning to the Sheffield area was conducted from May 1984 to April 1986. LT+ETEC were found in 35 (5.8%) of 600 travellers to developed countries (mainly popular Mediterranean holiday resorts), 36 (11.3%) of 320 travellers to less-developed countries, and 11 (0.9%) of 1282 control patients whose illness was not associated with recent travel abroad. A seasonal peak of LT+ETEC infection was observed only in travellers to developed countries, with infections being significantly commoner in August to October. There was no significant deviation from expected age/sex distribution of LT+ETEC infection. Strains of LT+ETEC from travellers produced more toxin than strains from control patients, strains from travellers to less-developed countries producing most of all.Keywords:
Heat-labile enterotoxin
Enterotoxigenic Escherichia coli
The intracellular distribution of heat-labile enterotoxin in a human isolate of enterotoxigenic Escherichia coli varied significantly as a result of changing incubation time, media, and degree of aeration. Direct comparison with a K-12 plasmid recipient revealed a similar but less dramatic response to environmental factors.
Heat-stable enterotoxin
Enterotoxigenic Escherichia coli
Heat-labile enterotoxin
Incubation period
Cite
Citations (9)
Enterotoxigenic Escherichia coli
Heat-stable enterotoxin
Heat-labile enterotoxin
Cite
Citations (0)
The text analysed biological characteristics,molecular mechanisms and application of heat labile(LT)and heat stable(ST)enterotoxin.First of all,different mutants of LT that have been demonstrated as mucosal adjuvants were constructed by site directed mutagenesis and proved to be the excellent candidates of CT.Next,genetically engineered vaccine of fused LT and ST,which was beneficial to preventing and treating diarrhea, was constructed .These results give a base for further research on enterotoxin in ETEC.
Enterotoxigenic Escherichia coli
Heat-stable enterotoxin
Heat-labile enterotoxin
Cite
Citations (0)
We demonstrated that both the A and B subunits of heat-labile enterotoxin from Escherichia coli are located in the periplasm. The toxin was shown to form aggregates in Tris-EDTA buffers which are routinely used for isolating membranes. The aggregates pellet upon centrifugation, and this may explain why several previous investigators have concluded that enterotoxin is associated with membranes.
Heat-stable enterotoxin
Heat-labile enterotoxin
Cite
Citations (98)
The Escherichia coli type II heat-labile enterotoxin LT-IIb IIb consists of a single A polypeptide and five B polypeptides. The A polypeptide is responsible for the toxic activity, and the B polypeptides function to bind the toxin to gangliosides on the surface of the plasma membrane. Previous studies on the related type II enterotoxin LT-IIa demonstrated the importance of threonine (Thr) residues at positions 13, 14, and 34 in the mature B polypeptide for ganglioside GD1bp-binding activity. In this study, we used sitespecific mutagenesis to investigate ganglioside GD1a-binding activity of the B polypeptide of LT-IIb. We determined that Thr-13 and Thr-14 were involved in binding of ganglioside GD1a by the B polypeptides of LT-IIb but that Thr-34 was not essential. Substitution of serine, but not other amino acids, at position 13 or 14 in the B polypeptide of LT-IIb resulted in retention of ganglioside-binding activity equivalent to that of the wild-type enterotoxin, providing strong evidence that the hydroxyl groups of threonine or serine at positions 13 and 14 are important for the ganglioside-binding activity of LT-IIb. Chimeric genes that expressed hybrids of the B polypeptides of LT-IIb and LT-IIa were also constructed, and analysis of the hybrids showed that the specificity of their ganglioside-binding activity was determined by the N-terminal half of the molecule.
Heat-labile enterotoxin
Ganglioside
Heat-stable enterotoxin
Cite
Citations (23)
Enterotoxigenic Escherichia coli
Heat-labile enterotoxin
Heat-stable enterotoxin
Mitomycin C
Cite
Citations (0)
The DNA colony hybridization assay was used to identify enterotoxigenic Escherichia coli among E. coli isolated from 803 swine with diarrhea at 10 farms in Thailand. Between 5 September and 8 December 1981, enterotoxigenic E. coli were identified in 40% of 58 litters of piglets under 10 days old and 17% of 29 litters between 10 and 21 days old with diarrhea at farms at four different locations in Thailand. All E. coli that hybridized with one or more of the three enterotoxin gene probes produced heat-labile or heat-stable toxin or both, as determined by testing culture supernatants in the Y1 adrenal and suckling mouse assays. The DNA colony hybridization technique is a specific method of identifying enterotoxigenic E. coli from swine and can be used to further characterize these enteric pathogens.
Enterotoxigenic Escherichia coli
Heat-stable enterotoxin
DNA–DNA hybridization
Cite
Citations (14)
Enterotoxigenic Escherichia coli (ETEC) strains are important pathogens for humans and farm animals such as pigs. Porcine ETEC strains induce diarrhea through the production of heat-labile enterotoxin (LT) and/or heat-stable enterotoxins (pSTa/STb). Although LT secretion levels differ between porcine ETEC strains, and this has been linked to virulence, it is unclear whether ST secretion levels also differ between porcine ETEC strains. In addition, the molecular mechanism underlying different LT secretion levels has not been elucidated. In this work, multiple porcine ETEC strains were assessed for their capacity to produce and secrete the enterotoxins LT, pSTa, and STb. The strains differed greatly in their capacity to secrete LT, pSTa, and STb. Remarkably, in some strains, periplasmic production did not correlate with their ability to secrete LT, resulting in high periplasmic production and low LT secretion levels. Furthermore, the results indicated that the type II secretion system (T2SS) protein YghG plays a regulatory role in controlling LT secretion levels. These findings highlight YghG as an important mediator of the secretion of the heat-labile enterotoxin LT by porcine ETEC strains and provide better insights into ETEC enterotoxin secretion.IMPORTANCE Enterotoxigenic E. coli strains are a major health concern. Enterotoxins secreted by enterotoxigenic E. coli are crucial for diarrhea induction. Enterotoxin secretion levels differ between strains; however, it is currently unclear what drives these differences. The discrepancy in the production and secretion capacities of enterotoxins in ETEC is important to clarify their function involved in diarrhea induction. Our results further deepen our understanding of how type II secretion system (T2SS) components of ETEC control enterotoxin secretion levels and may lay the foundation for a better understanding of ETEC molecular pathogenesis.
Enterotoxigenic Escherichia coli
Heat-stable enterotoxin
Cite
Citations (12)
Nine different methods for detecting enterotoxin of Escherichia coli were studied and compared. We found rabbit ileal-loop test and suckling mouse assay were both quite accurate and reliable for detecting heat labile toxin (LT) and heat stable toxin (ST) of enterotoxigenic Escherichia coli (ETEC). Mouse ileal-loop test was simple, but its sensitivity and specificity were comparatively low. CHO cell-culture assay might be more sensitive and specific. LT-DNA probe was the most sensitive and specific method. In practical application, PIHT (plate immunohemolytic test), Biken's, SPA-CoA and ELISA methods are recognized as simple, rapid, sensitive and specific methods for detecting ETEC-LT. These methods can be selected for use in clinical laboratory.
Enterotoxigenic Escherichia coli
Heat-stable enterotoxin
Heat-labile enterotoxin
Escherichia
Cite
Citations (1)
SYNTHESIS OF A HEAT-STABLE ENTEROTOXIN PRODUCED BY A HUMAN STRAIN OF ENTEROTOXIGENICEscherichia coli
Abstract A heat-stable enterotoxin, produced by a human strain of enterotoxigenic Escherichia coli, was synthesized by a solution method. The synthesized peptide has the same biological and physicochemical properties as those of native toxin.
Enterotoxigenic Escherichia coli
Heat-stable enterotoxin
Strain (injury)
Heat-labile enterotoxin
Cite
Citations (9)