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Enterotoxigenic E. Coli (enterotoxigenic + e._coli)

Distribution by Scientific Domains
Life Sciences50%
Medical Sciences33%

Selected Abstracts

Visualization of Surface-specific Antigens in Various Strains of Enterotoxigenic E. coli

ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2005
S. Lüdi
Proteinaceous surface antigens of enterotoxigenic E. coli (ETEC) appear as pili, and are important virulence factors as they allow bacteria to attach to the small intestinal mucosa. Surface antigens are classified as colonization factor antigens (CFA) and coli surface antigens (CS). Known groups include CFA/I, CFA/II (consisting of CS1, CS2 and CS3), CA/III and CFA/IV (consisting of CS4, CS5 and CS6). The goal of the present study was to examine the morphology of pili by transmission electron microscopy (TEM) and to localize specific surface antigens by immunolabelling. Using different strains of E. coli grown under various culture conditions, pili were visualized by negative staining and corresponding surface antigens were demonstrated by immunogold-labelling using both polyclonal and monoclonal antibodies. Expression of pili was dependent on culture conditions and sample handling. In contrast to CFA/I and CS3, CS6 pili were not detectable after negative staining. Selected antibodies, however, allowed surface antigens to be demonstrated unequivocally. These results will be of value in investigating the expression of colonizing factors in genetically modified bacterial strains. [source]

Quantitative real-time PCR monitoring of Escherichia coli and Clostridium perfringens with oral administration of Lactobacillus plantarum strain Lq80 to weaning piglets

ANIMAL SCIENCE JOURNAL, Issue 6 2008
Shunsuke TAKAHASHI
ABSTRACT Levels of fecal or intestinal lactobacilli, Escherichia coli and Clostridium perfringens, and the prevalence of clostridial alpha toxin gene and heat-stable toxin (ST) gene of enterotoxigenic E. coli (ETEC) were monitored in weaned piglets before (day 0) and during (days 7, 14, and 21) the administration of Lactobacillus plantarum strain Lq80. Lactobacilli were enumerated in a culture-dependent method. The remainders were determined by quantitative real-time PCR. In this quantitative real-time PCR method, the detection limit was proved to be as low as 103 cells/g feces or intestinal contents. Number of lactobacilli increased from day 0 to day 7 (P < 0.05), to day 14 (P < 0.05), and to day 21 (P = 0.07) in the Lq80-administered group. L. plantarum contributed to as low as 10% of the lactobacillal population in the Lq80-administered group. The number of E. coli and C. perfringens, and the prevalence of alpha toxin gene in feces or intestinal contents of the Lq80-administered group decreased, at least in the first week of the postweaning period. Oral administration of L. plantarum strain Lq80 can stimulate the growth of indigenous lactobacilli and decrease ST-producing ETEC and C. perfringens in the intestine of postweaning piglets. [source]

Antimicrobial activity of five essential oils against origin strains of the Enterobacteriaceae family,

APMIS, Issue 1 2005
PEDRO PEŅALVER
An in vitro assay measuring the antimicrobial activity of essential oils of Coridothymus capitatus (Spanish origanum), Satureja montana, Thymus mastichina (Spanish Origanum majorana), Thymus zygis (Spanish variety of Thymus vulgaris) and Origanum vulgare has been carried out against poultry origin strains of Escherichia coli, Salmonella enteritidis and Salmonella essen, and pig origin strains of enterotoxigenic E. coli (ETEC), Salmonella choleraesuis and Salmonella typhimurium. Using the broth microdilution method, all the essential oils showed an MIC , 2% (v/v) for the two strains of E. coli. The essential oil that showed the highest antimicrobial activity against the four strains of Salmonella was Origanum vulgare (MIC , 1% v/v), followed by Thymus zygis (MIC ,2% v/v). Thymus mastichina inhibited all the microorganisms at the highest concentration, 4% (v/v), while the rest of the essential oils showed highly variable results. By chemotyping, higher inhibitory capacity was observed in the oils with a higher percentage of phenolic components (carvacrol and thymol) in comparison with oils containing the monoterpenic alcohol linalool. The results of this work confirm the antimicrobial activity of some essential oils, as well as their potential application in the treatment and prevention of poultry and pig diseases caused by salmonella. [source]

Virulence genes, serobiotypes and antibiotic resistance profile of Escherichia coli strains isolated from aquaculture and other sources

AQUACULTURE RESEARCH, Issue 7 2010
Surendraraj Alagarsamy
Abstract In order to determine the prevalence of pathogenic Escherichia coli, a total number of 155 E. coli isolates from aquaculture, clinical and veterinary sources were screened for seven pathogenic virulence markers and a house-keeping gene by a polymerase chain reaction. The targeted virulence genes included eaeA of enteropathogenic E. coli, elt and est of enterotoxigenic E. coli (ETEC), ipaH of enteroinvasive E. coli, pCVD432 of enteroaggregative E. coli, stx, hlyA and eaeA of shigatoxigenic E. coli (STEC) and Enterohaemorrhagic E. coli. All the isolates were positive for phoA, the house-keeping gene for E. coli. Among the 155 isolates, seven numbers (4.5%) harboured the virulence markers belonging to the pathogenic group ETEC and STEC. The virulent genes detected in these groups were elt, est, hlyA and stx. The sources of these virulence genes were fish (hlyA), shrimp (elt), feeder canal water (hlyA and elt) of aquaculture origin and from diarrhoea affected cow (hlyA, est and stx). The isolates with pathogenic traits belonged to the serogroups O6 or O29 and the remaining could not be typed. They showed resistance to two to four antibiotics out of the 12 antibiotics tested. Biotyping revealed that three isolates belonged to a single biotype (7333) and the remaining isolates were of diverse types. In conclusion, a molecular tool such as PCR proves as more effective tool for detection of this pathogen than the conventional methods. Detection of these emerging pathogens in aquaculture samples warrants for strict adherence to hygienic handling at retail outlets and proper cooking by the consumer before consumption. [source]

A method for fast and simple detection of major diarrhoeagenic Escherichia coli in the routine diagnostic laboratory

CLINICAL MICROBIOLOGY AND INFECTION, Issue 5 2007
S. Persson
Abstract A multiplex PCR was developed for the detection of the following genes characteristic of diarrhoeagenic Escherichia coli (DEC): verocytotoxins 1 (vtx1) and 2 (vtx2), characteristic of verocytotoxin-producing E. coli (VTEC); intimin (eae), found in enteropathogenic E. coli (EPEC), attaching and effacing E. coli and VTEC; heat-stable enterotoxin (estA) and heat-labile enterotoxin (eltA), characteristic of enterotoxigenic E. coli (ETEC); and invasive plasmid antigen (ipaH), characteristic of enteroinvasive E. coli (EIEC) and Shigella spp. The method allowed the simultaneous identification of all six genes in one reaction, and included a 16S rDNA internal PCR control. When applied to pure cultures from a reference strain collection, all virulence genes in 124 different DEC strains and 15 Shigella spp. were identified correctly, and there were no cross-reactions with 13 non- E. coli species. The detection limit of the method was 102,103 DEC CFU/PCR in the presence of 106 non-target cells. When the multiplex PCR was tested with colonies from plate cultures of clinical stool samples, it was a faster, more sensitive, less expensive and less laborious diagnostic procedure than DNA hybridisation. When used with DNA purified from spiked stool samples (by two different commercial kits), the method had a detection limit of 106 CFU/mL stool sample. [source]