background and aims: among the bacterial agents, the most common cause of diarrheal disease is entrotoxigenic escherichia coli. letal toxin b (ltb) subunit of lt toxin could induce six-month immunity. clostridium botulinum causes botulism disease. bont/a-hc toxin subunit could induce two years immunity against this disease. it seems that the immunogenicity potency of these two subunits may infl...

A first-generation oral inactivated whole-cell enterotoxigenic Escherichia coli (ETEC) vaccine, comprising formalin-killed ETEC bacteria expressing different colonization factor (CF) antigens combined with cholera toxin B subunit (CTB), when tested in phase III studies did not significantly reduce overall (generally mild) ETEC diarrhea in travelers or children although it reduced more severe ET...

We determined the complete nucleotide sequence of the toxB gene (375 base pairs in length), which encodes the B subunit of heat-labile enterotoxin produced from Escherichia coli pathogenic for humans (hLT). The amino acid sequence of the B subunit of hLT was deduced from the nucleotide sequence. Consequently, it has become possible to study the homology between the B subunits of three similar t...

With the plasmid DNA from a clinical isolate of enterotoxigenic Escherichia coli (ETEC) H 10407 as template, PCR-mediated cloning of the sequence encoding the heat-labile toxin B subunit (L T -B) has been carried out. Then this sequence was recloned into the pTrc 99A and pET23a expression vectors to give the pJasmids pTRCLTB and pETLTB, respectively. After induction, the former plasmid provides...

Human and porcine enterotoxigenic strains of Escherichia coli were cultivated in tryptone-yeast extract medium or brain heart infusion broth and tested for production of heat-labile enterotoxin by the GM1 ganglioside enzyme-linked immunosorbent assay (GM1-ELISA) and the Y1 adrenal cell assay. When testing for enterotoxigenicity by the GM1-ELISA technique, homologous antisera for human and porci...

Two of 49 cytolethal distending toxin-producing strains of Escherichia coli isolated from human stools contained the gene coding for heat-stable enterotoxin b (STb), as detected by a colony hybridization assay. The STb gene was found to be on a 70-kb plasmid also coding for heat-labile enterotoxin (pLT-I). Restriction endonuclease analysis showed the STb gene from human isolates to be similar t...

the aim of this study was to determine the occurrence of enterotoxigenic and enteroaggregative escherichia coli strains and antibiotic resistance of the isolates in raw milk and unpasteurized cheese. out of 200 samples of raw milk and 50 samples of unpasteurized cheeses, 96 and 24 strains of e. coli were isolated, respectively. polymerase chain reaction (pcr) was used to detect the genes encodi...

materials and methods two-hundred pasteurized (n = 100) and nonpasteurized (n = 100) cheese samples were collected. the initial isolation was performed on pemba specific medium. antibiotic susceptibility testing was performed using several antibiotic disks, according to the guidelines of the clinical laboratory and standards institute. specific primers amplifying the hbla enterotoxin-encoding g...