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K A Bettelheim

Publications and source records attributed to K A Bettelheim.

At least 55 records · Page 3Linked to original sources
PubMed1997

Isolation of verotoxigenic Escherichia coli from the Tasmanian environment.

Growing concerns on the emergence of verotoxin producing Escherichia coli (VTEC) in Australia have focused our attention on the possible sources of VTEC within the island state of Tasmania. An analysis of 156 food samples and 194 water samples obtained from various areas revealed evidence of eight possible sources. Six strains, with serotypes Ont:Hnt, O86:H-, O88:H-, O126:H21 and O134:H-, were isolated from water samples. Two VTEC of serotypes Ont:H8, 081:H- were isolated from raw meat samples. The waterborne isolates produced verocytotoxin. VT1, while both foodborne isolates were strong producers of VT2. Three VTEC isolates produced haemolysins, only one produced enterohaemolysin (EntHly) and the remaining were reported with alpha-haemolysin (alpha-Hly) activity. An important feature in the majority of isolates from water was their lack of ability to ferment lactose these isolates are routinely overlooked in public health laboratories.

Animals↗
PubMed1996

Haemolytic-uraemic syndrome in the Hunter: public health implications.

Three cases of haemolytic-uraemic syndrome in the Hunter area were reported in February 1995. An investigation was initiated to identify any verocytotoxic Escherichia coli in clinical samples that could be associated with the development of the disease. Escherichia coli O6:H- and O2:H7 were isolated from Case 1. No organisms were identified for Case 2, and Case 3 samples yielded Campylobacter jejuni. In addition, efforts were made to trace sources of any such pathogens in food samples or in the environment generally. Shiga-like toxins were found in meat products sampled from butchers' shops patronised by the families of the three cases. However, it was not found possible to match stool samples with samples of food from sources used by the families of the children. Environmental factors seemed likely to have played a significant role in the development of haemolytic-uraemic syndrome in Case 3. It is suggested that the incidence of the disease may be reduced by increasing the frequency of testing of meat products for Shiga-like toxins I and II and through educational and research programs.

Adolescent↗
PubMed1996

Enterohaemorrhagic Escherichia coli: a new problem, an old group of organisms.

All mammals are colonised by Escherichia coli generally at birth and these organisms become part of their intestinal flora for the rest of their lives. New types are acquired generally by an oral route. Some E coli are pathogenic and some may have a far more enhanced ability to colonise the human intestine than most others. Recently enterohaemorrhagic E coli have emerged. They can cause a number of intestinal illnesses in humans including bloody diarrhoea and haemolytic uraemic syndrome. These organisms produce a number of virulence factors particularly the Shiga-like toxins (verotoxins). The intestines of animals may be the reservoir of these organisms for human infection, and cattle particularly have been shown to harbour them. Food, especially undercooked meat products, have been associated with a number of outbreaks throughout the world. While a certain serotype O157.H7 has been associated with many outbreaks throughout the world, other serotypes, particularly O111.H-, have also been reported. This latter serotype appears to be more common in Australia.

Adult↗
PubMed1996

Controlled study of cytolethal distending toxin-producing Escherichia coli infections in Bangladeshi children.

The role of cytolethal distending toxin (CDT)-producing Escherichia coli, a newly described category of E. coli, in the causation of diarrhea was studied by screening E. coli isolates from 546 children < 5 years of age with diarrhea and 215 matched controls without diarrhea by using a specific DNA probe. Although CDT-positive E. coli strains were isolated from more children with diarrhea than from healthy controls (3.1 versus 0.93%), this difference did not reach statistical significance (P = 0.082). All CDT-positive strains also possessed the virulence factors of enteropathogenic E. coli or enteroaggregative E. coli isolates.

Acute Disease↗
PubMed1995

Virulence factors associated with strains of Escherichia coli from cases of sudden infant death syndrome (SIDS).

Strains of Escherichia coli isolated from cases of Sudden Infant Death Syndrome, healthy infants and infants that died of other causes were subjected to a series of tests with particular reference to serotyping, toxigenicity and adherence factors. E. coli from SIDS infants tended to have a low hydrophobicity and high toxigenicity, compared to those from healthy infants, while no notable differences in haemagglutination patterns were observed between these two groups of strains.

Animals↗
PubMed1995

Identification of enterohaemorrhagic Escherichia coli by means of their production of enterohaemolysin.

With increasing interest in verocytotoxigenic Escherichia coli (VTEC) being associated with both human and animal infection, a simple system of rapidly identifying the majority of VTEC has been devised. This depends on the fact that most VTEC produce enterohaemolysin, which is rarely produced by non-VTEC. By employing two media, traditional sheep blood agar (SBA) and washed sheep blood agar supplemented with calcium (WSBA-Ca), enterohaemolysin-producing strains can be easily differentiated from other E. coli enabling most VTEC types, including ones belonging to serogroups other than O157, to be isolated.

Animals↗
PubMed1994

Hemagglutinating properties of enteroaggregative Escherichia coli.

Many intestinal bacterial pathogens possess hemagglutinating properties, which are indicative of their adhesive properties to the intestinal mucosal surface. To understand the bacteria-mucosa interaction, 41 strains of enteroaggregative Escherichia coli (EAggEC), a recently described category of diarrheagenic E. coli, isolated mostly from children with diarrhea in Bangladesh, India, Thailand, Central America, and South America were screened for mannose-sensitive hemagglutination and mannose-resistant hemagglutination of erythrocytes from humans, rats, mice, sheep, cattle, and rabbits. Some strains demonstrated mannose-sensitive hemagglutination of erythrocytes. Most isolates showed mannose-resistant hemagglutination of erythrocytes from all species except rabbits. The hemagglutination patterns could be classified into 18 groups. Studies with three selected isolates suggested that hemagglutinins are cell bound and are protein in nature. On the basis of the pattern of inhibition of hemagglutination by various chemicals, 39 isolates were classified into 19 groups. Hemagglutinations of many isolates were inhibited by sialic acid-containing compounds, suggesting that these compounds may be the receptors for these organisms on erythrocytes and possibly on the intestinal mucosa. These data indicate that strains of EAggEC are a heterogeneous group of organisms with different types of hemagglutinins or adhesins for the intestinal mucosal surface. Also, the adhesion characteristics of EAggEC strains may be too complex to be assessed by simple hemagglutination tests.

Adhesins, Escherichia coli↗
PubMed1993

The isolation of cytotoxic necrotizing factor (CNF)-producing Escherichia coli from the intestinal contents of babies who died of sudden infant death syndrome (SIDS) and other causes as well as from the faeces of healthy babies.

Strains of Escherichia coli producing cytotoxic necrotizing factor (CNF) have been isolated from intestinal contents of 16.8% of babies who died of Sudden Infant Death Syndrome (SIDS) and 16.5% of faeces from healthy babies. While no difference in CNF carriage was seen, it is noteworthy that these CNF-producing E. coli are present in such specimens. Some of the CNF-producing E. coli belonged to serotypes associated with this factor in other parts of the world.

Bacterial Toxins↗
PubMed1993

Examination of archetypal strains of enteropathogenic Escherichia coli for properties associated with bacterial virulence.

Nine strains of Escherichia coli isolated from infants with diarrhoea between 1947 and 1960 and designated "enteropathogenic" were examined for phenotypic and genetic characters associated with virulence. Each strain belonged to a different serotype. All the isolates were historically significant in that they were amongst the first strains of E. coli reported to be causally associated with infantile diarrhoea. Five strains possessed the virulence properties of class I enteropathogenic E. coli (EPEC). All these strains were isolated originally from symptomatic children during outbreaks of diarrhoea. Two isolates from sporadic cases of diarrhoea fulfilled the criteria for classification as class II EPEC. One strain was identified as enteroaggregative E. coli and the other carried no known virulence-associated properties. These findings indicate that most early isolates of E. coli which were designated "enteropathogenic" were indeed EPEC, as currently defined.

Bacterial Adhesion↗
PubMed1992

Distribution of toxigenic Escherichia coli serotypes in the intestines of infants.

As part of an ongoing study into the pathogenesis of sudden infant death syndrome (SIDS), the distribution of serotypes of toxigenic and non-toxigenic Escherichia coli within the gastrointestinal tract of babies who had died was investigated. Escherichia coli isolates from the mid-ileum, colon and rectum of six SIDS cases and one case which had died suddenly and unexpectedly but had underlying cardiac pathology were "O" serogrouped and examined for verocytoxic activity and production of heat-labile enterotoxin. In addition, the effect of storage of gut specimens and rectal swabs at 4 degrees C on isolation of toxigenic strains was studied in three of the cases. A diversity of serogroups and toxigenicity was a general finding, however, strains found in the proximal gut were also cultured from the rectum, indicating that faecal specimens would be a valid tool in investigating the role of these organisms in SIDS cases compared with healthy controls. Storage for up to 5 days at 4 degrees C had no appreciable effect on isolation rates of toxigenic bacteria.

Animals↗
PubMed1990

HEp-2 cell adherence and Vero cell cytotoxin production by EPEC strains isolated from children with diarrhoea in New Zealand.

A total of 112 EPEC strains isolated from children with diarrhoea in New Zealand were examined for mannose-resistant HEp-2 cell adherence and production of exotoxins. Enterotoxin production was not detected in any of the strains examined. Verotoxin production was detected in 13 (11.6%) strains and of these 4 were also found to adhere to HEp-2 cells. HEp-2 cell adherence was displayed by a total of 29 (25.8%) strains of which 22 were diffusely adherent. Only 3 (2.7%) strains were shown to belong to the new virulence phenotype, entero-aggregative adherence, when examined in the adherence assay. We identified one strain with the novel characteristic of causing detachment of HEp-2 cells from glass coverslips and are further investigating this possible virulence mechanism. These results suggest that if EPEC strains are to be considered as a cause of diarrhoea, the search for new virulence factors must be extended.

Animals↗
PubMed1990

Serotypes of Escherichia coli that hybridized with DNA probes for genes encoding Shiga-like toxin I, Shiga-like toxin II, and serogroup O157 enterhemorrhagic E. coli fimbriae isolated from adults with diarrhea in Thailand.

Escherichia coli strains isolated from adults with diarrhea in Bangkok, Thailand, were examined for hybridization with DNA probes for genes that code for Shiga-like toxin (SLT)-I, SLT-II, and serogroup O157 enterhemorrhagic E. coli (EHEC) fimbriae. Seven isolates that hybridized with the SLT-I, SLT-II, and O157 EHEC fimbria probes and produced verocytotoxin (VT; group A) were isolated from two patients with diarrhea. Two strains that hybridized with only the SLT-II probe and the O157 EHEC fimbria probe and were VT+ (group B) were isolated from two patients with diarrhea, 7 strains that hybridized with only the SLT-II probe and were VT+ (group C) were isolated from two patients with diarrhea, and 26 strains that hybridized with only the O157 EHEC fimbria probe and were VT- (group D) were isolated from four patients with diarrhea. Seven strains in group A had serotypes O2:H1 (n = 1), O110:H19 (n = 1), and Ont:H8 (n = 5); 2 strains in group B were O112ab:H21 (n = 1) and O113:H21 (n = 1); 7 strains in group C were O6:H28 (n = 1), O22:H16 (n = 1), O52:H25 (n = 1), O112ab:H21 (n = 1), OR:H45 (n = 2), and OR:H11 (n = 1); and 26 strains in group D were O76:H7 (n = 18), O146:H3 (n = 2), O146:H10 (n = 1), O146:Hnt (n = 1), OR:H16 (n = 1), Ont:H2 (n = 1), Ont:H8 (n = 1) and Ont:H16 (n = 1). In Thailand, E. coli strains that hybridized with SLT-I, SLT-II, and O157 EHEC fimbria probes were of a variety of serotypes, none of which were O157:H7.

Adult↗