scholarly journals Genetic Rearrangements of the Regions Adjacent to Genes Encoding Heat-Labile Enterotoxins (eltAB) of EnterotoxigenicEscherichia coli Strains

2000 ◽  
Vol 66 (1) ◽  
pp. 352-358 ◽  
Author(s):  
Stefan Schlör ◽  
Sabine Riedl ◽  
Julia Blaß ◽  
Joachim Reidl
Keyword(s):  
Escherichia Coli ◽  
Dna Sequences ◽  
Insertion Sequence ◽  
Is Element ◽  
Heat Stable ◽  
Heat Labile ◽  
Genes Encoding ◽  
Encoding Genes ◽  
Genetic Rearrangements ◽  
Dependent Mechanism

ABSTRACT One of the most common bacterially mediated diarrheal infections is caused by enterotoxigenic Escherichia coli (ETEC) strains. ETEC-derived plasmids are responsible for the distribution of the genes encoding the main toxins, namely, the heat-labile and heat-stable enterotoxins. The origins and transfer modes (intra- or interplasmid) of the toxin-encoding genes have not been characterized in detail. In this study, we investigated the DNA regions located near the heat-labile enterotoxin-encoding genes (eltAB) of several clinical isolates. It was found that the eltAB region is flanked by conserved 236- and 280-bp regions, followed by highly variable DNA sequences which consist mainly of partial insertion sequence (IS) elements. Furthermore, we demonstrated that rearrangements of the eltAB region of one particular isolate, which harbors an IS91R sequence next toeltAB, could be produced by a recA-independent but IS91 sequence-dependent mechanism. Possible mechanisms of dissemination of IS element-associated enterotoxin-encoding genes are discussed.

scholarly journals Little Heterogeneity among Genes Encoding Heat-Labile and Heat-Stable Toxins of Enterotoxigenic Escherichia coli Strains Isolated from Diarrheal Pigs

2009 ◽  
Vol 75 (19) ◽  
pp. 6402-6405 ◽  
Author(s):  
Chengxian Zhang ◽  
Dana Rausch ◽  
Weiping Zhang
Keyword(s):  
Escherichia Coli ◽  
Enterotoxigenic Escherichia Coli ◽  
Enterotoxin Gene ◽  
Toxin Genes ◽  
Heat Stable ◽  
Heat Labile ◽  
Genes Encoding

ABSTRACT To examine whether the heat-labile enterotoxin gene in porcine enterotoxigenic Escherichia coli (ETEC) strains is as divergent as in human ETEC strains, we sequenced the heat-labile and heat-stable toxin genes from 52 and 33 porcine ETEC strains, respectively. We found that the STa gene is identical, that the LT gene has only two mutations in 4 (of 52) strains, and that both mutations cause a reduction in GM1 binding and toxicity.

scholarly journals Molecular Epidemiology of NDM-1-Producing Enterobacteriaceae and Acinetobacter baumannii Isolates from Pakistan

2014 ◽  
Vol 58 (9) ◽  
pp. 5589-5593 ◽  
Author(s):  
Anna L. Sartor ◽  
Muhammad W. Raza ◽  
Shahid A. Abbasi ◽  
Kathryn M. Day ◽  
John D. Perry ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Molecular Epidemiology ◽  
Genetic Relatedness ◽  
Antibiotic Resistance Genes ◽  
Enterobacter Cloacae ◽  
Content Type ◽  
Plasmid Replicon ◽  
Genes Encoding ◽  
Clonal Spread ◽  
Encoding Genes

ABSTRACTThe molecular epidemiology of 66 NDM-producing isolates from 2 Pakistani hospitals was investigated, with their genetic relatedness determined using repetitive sequence-based PCR (Rep-PCR). PCR-based replicon typing and screening for antibiotic resistance genes encoding carbapenemases, other β-lactamases, and 16S methylases were also performed. Rep-PCR suggested a clonal spread ofEnterobacter cloacaeandEscherichia coli. A number of plasmid replicon types were identified, with the incompatibility A/C group (IncA/C) being the most common (78%). 16S methylase-encoding genes were coharbored in 81% of NDM-producingEnterobacteriaceae.

Use of a Multiplex PCR System for the Simultaneous Detection of Heat Labile Toxin I and Heat Stable Toxin II Genes of Enterotoxigenic Escherichia coli in Skim Milk and Porcine Stool

1998 ◽  
Vol 61 (2) ◽  
pp. 141-145 ◽  
Author(s):  
HAU-YANG TSEN ◽  
LIANG-ZHAO JIAN ◽  
WAN-RONG CHI
Keyword(s):  
Escherichia Coli ◽  
Multiplex Pcr ◽  
Simultaneous Detection ◽  
Skim Milk ◽  
Pcr Primers ◽  
Enterotoxigenic Escherichia Coli ◽  
Farm Animals ◽  
Target Cells ◽  
Heat Stable ◽  
Heat Labile

Enterotoxigenic Escherichia coli (ETEC) strains which produce heat labile and/or heat stable toxins (LT and ST) may cause diarrhea in humans and farm animals. Using PCR primers specific for the LT I and ST II genes, a multiplex PCR system which allows detection of LT I- and ST II-producing ETEC strains was developed. When skim milk was used for a PCR assay, it was found that if target cells in the sample were precultured in MacConkey broth for 8 h prior to PCR as few as 100 cells per ml of the sample could be detected. Without the preculture step, 104 CFU of target cells per 0.2 g of porcine stool specimen were required to generate visible PCR products. The multiplex PCR System can be used for rapid testing of fecal specimens, food and possibly environmental samples for the presence of ETEC strains.

scholarly journals Does enteropathogenic Escherichia coli produce heat-labile enterotoxin, heat-stable enterotoxins a or b, or cholera toxin A subunits?

1984 ◽  
Vol 46 (2) ◽  
pp. 612-614 ◽  
Author(s):  
S A Long-Krug ◽  
C S Weikel ◽  
K T Tiemens ◽  
E L Hewlett ◽  
M M Levine ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cholera Toxin ◽  
Enteropathogenic Escherichia Coli ◽  
Toxin A ◽  
Heat Stable ◽  
Heat Labile

scholarly journals Plasmid Coding for Drug Resistance and Production of Heat-Labile and Heat-Stable Toxins Harbored by an Escherichia coli Strain of Human Origin

1983 ◽  
Vol 39 (2) ◽  
pp. 970-973 ◽  
Author(s):  
M. Lourdes M. Silva ◽  
Isabel C. A. Scaletsky ◽  
M. Henriqueta L. Reis ◽  
M. Heloiza T. Affonso ◽  
Luiz R. Trabulsi
Keyword(s):  
Escherichia Coli ◽  
Drug Resistance ◽  
Coli Strain ◽  
Human Origin ◽  
Heat Stable ◽  
Heat Labile

scholarly journals Isolation of enterotoxigenicEscherichia colifrom British troops in Saudi Arabia

1995 ◽  
Vol 115 (3) ◽  
pp. 455-463 ◽  
Author(s):  
G. A. Willshaw ◽  
T. Cheasty ◽  
B. Rowe ◽  
H. R. Smith ◽  
D. N. Faithfull-Davies ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Saudi Arabia ◽  
General Hospital ◽  
Dna Probes ◽  
Enterotoxin Gene ◽  
Heat Stable ◽  
Heat Labile ◽  
Enterotoxin Genes ◽  
New Type ◽  
Flagellar Antigen

SummarySpecimens from 181 patients with diarrhoea were examined by a Military General Hospital in a 3-month period during deployment of troops to Saudi Arabia in 1990/1. DNA probes for heat labile (LT) and heat stable (ST) enterotoxin genes identified enterotoxigenicEscherichia coli(ETEC) in 47 of the specimens (26%) and 49 ETEC strains were isolated. The majority (55%) belonged to a novel ETEC serotype having the O-antigen 159 and a flagellar antigen designated as a provisional new type. They produced ST and the coli surface associated antigen (CS)6. Strains of serotype O6:H16 represented 22% of the ETEC examined. They produced ST, LT and CSS together with either CS1 or CS2. The remaining ETEC belonged to seven O:H serotypes. Overall, ST was the only enterotoxin gene identified in 73% of the ETEC and 67% of the strains expressed CS6 in the absence of other colonization antigens. Resistance to three or more antibiotics was observed in 53% of the ETEC, including most of the O159 strains.

scholarly journals Simultaneous Exposure to Escherichia coli Heat-Labile and Heat-Stable Enterotoxins Increases Fluid Secretion and Alters Cyclic Nucleotide and Cytokine Production by Intestinal Epithelial Cells

2014 ◽  
Vol 82 (12) ◽  
pp. 5308-5316 ◽  
Author(s):  
Lisa T. Read ◽  
Rachel W. Hahn ◽  
Carli C. Thompson ◽  
David L. Bauer ◽  
Elizabeth B. Norton ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Epithelial Cells ◽  
Diarrheal Disease ◽  
Water Movement ◽  
Intestinal Epithelial Cells ◽  
Intestinal Lumen ◽  
Intestinal Epithelial ◽  
Simultaneous Exposure ◽  
Heat Stable ◽  
Heat Labile

ABSTRACTEnterotoxigenicEscherichia coli(ETEC) is a significant cause of diarrheal disease and death, especially in children in developing countries. ETEC causes disease by colonizing the small intestine and producing heat-labile toxin (LT), heat-stable toxin (ST), or both LT and ST (LT+ST). The majority of ETEC strains produce both ST and LT. Despite the prevalence of LT+ST-producing organisms, few studies have examined the physiologic or immunologic consequences of simultaneous exposure to these two potent enterotoxins. In the current report, we demonstrate that when LT and ST are both present, they increase water movement into the intestinal lumen over and above the levels observed with either toxin alone. As expected, cultured intestinal epithelial cells increased their expression of intracellular cyclic GMP (cGMP) when treated with ST and their expression of intracellular cyclic AMP (cAMP) when treated with LT. When both toxins were present, cGMP levels but not cAMP levels were synergistically elevated compared with the levels of expression caused by the corresponding single-toxin treatment. Our data also demonstrate that the levels of inflammatory cytokines produced by intestinal epithelial cells in response to LT are significantly reduced in animals exposed to both enterotoxins. These findings suggest that there may be complex differences between the epithelial cell intoxication and, potentially, secretory outcomes induced by ETEC strains expressing LT+ST compared with strains that express LT or ST only. Our results also reveal a novel mechanism wherein ST production may reduce the hosts' ability to mount an effective innate or adaptive immune response to infecting organisms.

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