E coli O157

Am J Emerg Med, 1994 May, 12(3), 358 - 63
Hemolytic uremic syndrome: just another case of gastroenteritis?
Leo PJ, Cooper C, Songco C.
Hemolytic uremic syndrome (HUS), the most common cause of acute renal failure in childhood, has the potential to progress to a life-threatening illness . Its incidence in North America is increasing . Several studies have shown that Escherichia coli O157:H7 is associated with HUS . Although this pathogen was first recognized more than 10 years ago and is relatively common, many physicians are not aware of this diagnosis let alone the spectrum of illness associated with the bacteria . This case exemplifies what appears initially as gastroenteritis but, ultimately, becomes the final diagnosis of HUS . A case is presented to provide additional education to ensure the E coli O157:H7 infection is considered in the differential diagnosis of persons who present with bloody diarrhea.

J Clin Microbiol, 1994 May, 32(5), 1172 - 8
Humoral immune responses to Shiga-like toxins and Escherichia coli O157 lipopolysaccharide in hemolytic-uremic syndrome patients and healthy subjects; Greatorex JS et al.; Shiga-like-toxin (SLT)-producing Escherichia coli strains, especially serotype O157:H7, are important causes of bloody diarrhea and are associated with the development of hemolytic-uremic syndrome (HUS) . Enzyme-linked immunosorbent assays (ELISAs) were developed for the serologic detection of immunoglobulin M (IgM), IgG, and IgA to Shiga toxin (ST) and SLT-I, IgG to SLT-II, and IgM and IgG reactive against E . coli O157 lipopolysaccharide (LPS) . Serum samples were collected from 27 HUS patients (25 pediatric and 2 adult) and tested in the ELISAs . Of 27 patients, 10 (37%) were positive for at least one class of antibody to ST/SLT-I . None of the patients were positive for IgG antibody to SLT-II . Twenty-one of the 27 patients (78%) were positive for antibody to E . coli O157 LPS; 19 of 27 (70%) were positive for IgM, and 20 of 27 (74%) were positive for IgG . None of 48 control serum samples were positive in any of the toxin assays, and only 1 of 48 (2%) and 2 of 48 (4%) were positive for IgM and IgG, respectively, to E . coli O157 LPS . Twelve of the 24 patients (50%) from whom stool specimens were collected were positive by culture for E . coli O157 . Overall, serology and culture produced confirmation of infection by SLT-producing organisms in 23 of 27 (85%) HUS patients . A combination of ELISA for antibodies to E . coli O157 LPS and culture provided evidence for 22 of 27 (82%) of these patients . The results indicate that while ELISAs for ST/SLT-I and SLT-II antibodies were of limited diagnostic value, the ELISAs for IgM and IgG to E . coli O157 LPS provided valuable and sensitive adjuncts to culture.

J Med Microbiol, 1994 May, 40(5), 338 - 43
Variants of Shiga-like toxin II constitute a major toxin component in Escherichia coli O157 strains from patients with haemolytic uraemic syndrome; Russmann H et al.; The prevalence and genotype of Shiga-like toxins (SLTs) in Escherichia coli (O)157 strains from patients in Germany with haemolytic uraemic syndrome (HUS) were investigated . This was done by PCR amplification of the B-subunit genes with two primer pairs--one complementary to slt-IB, and the other homologous to both slt-IIB and slt-IIvB sequences . To distinguish between slt-II and slt-IIv, the amplified DNA was digested with restriction endonucleases HaeIII and FokI . Of the 38 strains examined, 17 harboured sequences for slt-IIv; four contained only slt-IIv, three carried both slt-IIv and slt-I, and 10 strains had slt-IIv and slt-II . A further three genotypes (slt-I, slt-II, slt-I/slt-II) were found in the remaining 21 strains resulting in a total of six slt genotypes . To determine whether the slt genes were expressed, and whether genotypes correlated with phenotypes, all strains were subjected to cytotoxicity assays and colony ELISA . All 38 strains displayed cytotoxic activity to Vero cells in similar quantities . The SLT-I-specific monoclonal antibody (MAb)13C4 reacted with all 10 strains in which slt-I sequences were identified . Colony blot ELISA with the SLT-II specific MAb11E10 detected 27 of 28 strains with slt-II sequences, but did not react with any of the seven strains that carried slt-IIv, or slt-I and slt-IIv . The high SLT variability shown here has diagnostic implications and may well have consequences for the host response in infections associated with these pathogens.

MMWR Morb Mortal Wkly Rep, 1994 Apr 1, 43(12), 213 - 6
Escherichia coli O157:H7 outbreak linked to home-cooked hamburger--California, July 1993; Hemolytic uremic syndrome: current pathophysiology and management; The combination of microangiopathic hemolytic anemia, thrombocytopenia, and renal failure, referred to as hemolytic uremic syndrome (HUS), is one of the main causes of acute renal failure in children . In most patients, infection with verotoxin-producing E . coli (VTEC, serotype O157:H7) precedes the development of bloody diarrhea (D+) characteristic of enteropathic HUS cases . In a minority, however, neither the enteropathogenic bacteria nor bloody diarrhea (D-) are documented . Despite that the pathogenesis of the two varieties remains unclear, clinical differentiation between D+ and D- HUS is extremely important to the final outcome . A more severe course, which may result in end stage renal disease, is frequently observed in the D- group.

J Clin Microbiol, 1994 Apr, 32(4), 955 - 9
Serodiagnosis by passive hemagglutination test and verotoxin enzyme-linked immunosorbent assay of toxin-producing Escherichia coli infections in patients with hemolytic-uremic syndrome; Yamada S et al.; Eight cases of hemolytic-uremic syndrome in which no pathogens were isolated were diagnosed serologically by a passive hemagglutination assay and a verotoxin (VT; Shiga-like toxin) enzyme-linked immunosorbent assay (ELISA) . The passive hemagglutination assay employed formalinized sheep erythrocytes sensitized with soluble native antigen or heat-treated antigen (lipopolysaccharide {LPS}) from Escherichia coli O26, O111, O128, and O157 or flagellar antigen of nine different H serogroups of E . coli: H2, H7, H8, H10, H11, H12, H18, H19, and H25 . All patients had antibodies against the native antigen and/or the LPS of E . coli O157, but positive agglutination with H7 was observed only in one patient . In the VT-ELISA with plates coated with purified VT 1 or VT 2, antibody against VT 2 was observed in the sera of five of six patients examined, but none of the patients possessed VT 1 antibody . These results indicate that the causative pathogen in these eight hemolytic-uremic syndrome cases is likely to be VT-producing E . coli O157 . The passive hemagglutination assay described here is a very sensitive, simple, and rapid method . This assay is highly recommended for the serological diagnosis of VT-producing E . coli infections, particularly in patients infected by serogroup O157 strains . Furthermore, the VT-ELISA is useful in studying the role of VT in hemolytic-uremic syndrome.

MMWR Morb Mortal Wkly Rep, 1994 Mar 18, 43(10), 192 - 4
Laboratory screening for Escherichia coli O157:H7--Connecticut, 1993; A rapid immunoblotting procedure for detecting serum antibodies to the lipopolysaccharide of Escherichia coli O157; Laboratory of Enteric Pathogens, Central Public Health Laboratory, London, UKAn immunoblotting method, which can be completed in one day, is described for the detection of serum antibodies to Escherichia coli O157 lipopolysaccharide.

FEMS Microbiol Lett, 1994 Jan 15, 115(2-3), 285 - 9
Ability of human sera to neutralise the activity of Vero cytotoxins VT1, VT2 and variant forms of VT2; Scotland SM et al.; Sera, from 17 patients with diarrhoea or haemolytic uraemic syndrome, and six healthy adults, were tested for neutralisation of Vero cytotoxins (VT) . For all 17 patients there was evidence of infection with Escherichia coli O157 . Sera from two controls but from none of the patients neutralised VT1, although two patients were infected by strains producing VT1 and VT2 . Sera from all six controls and 14 patients neutralised VT2 derived from strains 933 and E32511, but not variant forms of VT2 derived from strains E32511, E57, B2F1 and H.1.8 . This neutralising activity warrants further investigation, especially as many O157 VTEC carry both VT2 and VT2 variant genes.

J Pediatr, 1994 Jan, 124(1), 21 - 6
Epidemic Escherichia coli O157:H7 gastroenteritis and hemolytic-uremic syndrome in a Canadian inuit community: intestinal illness in family members as a risk factor; Rowe PC et al.; OBJECTIVE: To evaluate risk factors for childhood hemolytic-uremic syndrome (HUS) and gastroenteritis during an epidemic of Escherichia coli O157:H7 infection . DESIGN: Case-control study . SETTING: Remote Inuit community of Arviat in northern Canada . PARTICIPANTS: Of the 565 Arviat residents less than 15 years of age, 19 had HUS and 65 more had E . coli O157:H7 gastroenteritis . The 19 children with HUS were compared with 19 age- and gender-matched children with uncomplicated E . coli O157:H7 gastroenteritis, and both HUS and gastroenteritis patients were compared with 19 healthy control subjects . INTERVENTIONS: Questionnaire administered face-to-face to parents of participants in the home . MAIN OUTCOME MEASURES: Rates of exposure to foods, travel, sources of water, and gastrointestinal illness in family members . RESULTS: Patients with HUS and those with uncomplicated E . coli O157:H7 gastroenteritis differed only on measures of clinical severity . In the 7 days before the onset of gastrointestinal symptoms, children with HUS and those with uncomplicated gastroenteritis were more likely to have been exposed to a family member with diarrhea than were the healthy control subjects (odds ratio = 9 for HUS vs healthy control subjects; 95% confidence interval 2 to 43; p < 0.01) . Undercooked ground meat and foods traditionally consumed by the Inuit were not implicated as risk factors in E . coli O157:H7 infection . CONCLUSIONS: These findings emphasize the potential for extensive intrafamilial transmission of verotoxin-producing E . coli once infection is introduced into certain communities.

J Infect Dis, 1994 Jan, 169(1), 208 - 11
Community-wide outbreak of hemolytic-uremic syndrome associated with non-O157 verocytotoxin-producing Escherichia coli; Caprioli A et al.; From 20 April through 13 May 1992, 9 children were hospitalized with hemolytic-uremic syndrome in Lombardia, Italy, where only 14 cases of this syndrome had occurred in the preceding 4 years . Cases were scattered in a large area encompassing five provinces, and the source of the outbreak was not identified . Eight patients needed dialysis, and there was 1 death . Seven of the 9 cases were examined for evidence of infection by Vero cytotoxin (VT)-producing Escherichia coli (VTEC) . Six children had serum antibodies to the lipopolysaccharide of E . coli O111, and a VT-producing E . coli O111:NM was isolated from stool in 1 case . This is the first outbreak of VTEC infection recognized in Italy and the first associated with an E . coli serotype other than O157:H7.

Scand J Infect Dis, 1994, 26(6), 675 - 84
An outbreak of diarrhea due to verotoxin-producing Escherichia coli in the Canadian Northwest Territories; Orr P et al.; In the summer of 1991 a large outbreak of Escherichia coli O157:H7 associated diarrhea occurred in 6 Inuit communities in the Canadian Northwest Territories . The total population of these communities is 5,292 . Of the 521 individuals who developed diarrhea, 152 (29%) were positive for E . coli O157:H7 on stool culture or positive by verotoxin analysis . Median age was 6 years . The attack rate for children < 1 year was 43% in the major affected community of Arviat . Hemolytic-uremic syndrome (HUS) developed in 22 cases, and 2 patients died . Asymptomatic stool carriage of verotoxin-producing E . coli (VTEC) 2-5 weeks after diarrheal illness was noted in 4/28 persons followed prospectively . Epidemic curves, case-control studies and phage type testing suggested person-to-person transmission . The original source of infection was not identified, though a food source was suspected . VTEC were detected in 6 food samples (minced beef and caribou) taken from retail outlets and homes . Primary prevention of infection through health education and promotion activities, as well as long-term follow-up of HUS survivors, are indicated in this population.

Acta Microbiol Immunol Hung, 1994, 41(3), 259 - 64
Examination of verocytotoxin producing capacity and determination of the presence of Shiga-like toxin genes in human Escherichia coli isolates; Toth I et al.; A total of 93 wild type Escherichia coli of human origin (mostly representing intestinal isolates from Hungary) were examined for the presence of Shiga-like-toxin (SLT) genes using SLT-I, SLT-II and enterohemorrhagic E . coli (EHEC) specific DNA probes . The structural genes of the above specificity were labelled by random priming using 32-P-dCTP . E . coli strains investigated represented 16 serogroups: O1, O2, O4, O5, O6, O18, O25, O26, O45, O55, O111, O125, O126, O128, O157, O165, members of which were likely to produce verotoxin (VT) and strains of serotypes O11:NM, ONT:NM isolated from six haemorrhagic uraemic syndrome (HUS) patients . Out of these strains 51 were examined for in vitro VT production capacity . Only one strain (an O26:H11 from Germany) produced VT . This was also the only strain which proved to be positive with one of the SLT probes (SLT-II), and with the EHEC probe . From this strain a phage was isolated which was proven to be nonconvertible . These data support epidemiological and clinical observations about the very low occurrence or absence of EHEC in Hungary, in contrast to many European countries.

Appl Environ Microbiol, 1993 Dec, 59(12), 4223 - 9
An enzyme-linked immunosorbent assay-based isolation procedure for verotoxigenic Escherichia coli; Milley DG et al.; A colony enzyme-linked immunosorbent assay using the hydrophobic grid membrane filter format was developed for the isolation of verotoxigenic Escherichia coli from human and food samples . The method utilizes monoclonal antibodies directed against the verotoxins and is sensitive to all verotoxin 1- and/or 2-producing serotypes . E . coli that produced a minimum of 2 x 10(2) and 2 x 10(3) 50% cytotoxic doses per ml of verotoxins 1 and 2, respectively, were detectable . In a method comparison using human stool specimens, this procedure isolated 29% more E . coli O157 than did the standard sorbitol-MacConkey agar procedure, with no false-positive reactions . When applied to meat, 11 of 20 samples positive for verotoxin by polymyxin extraction yielded verotoxigenic E . coli of a variety of serotypes including O157:H7 . Four false positives were noted . This procedure provides a sensitive means for the isolation of verotoxigenic E . coli and should facilitate recovery of those serotypes that are otherwise indistinguishable from nonpathogenic strains.

Epidemiol Infect, 1993 Dec, 111(3), 439 - 47
Cattle as a possible source of verocytotoxin-producing Escherichia coli O157 infections in man; Chapman PA et al.; In May-June 1992 cases of infection with verocytotoxin-producing (VT+) Escherichia coli O157 in South Yorkshire could have been associated with prior consumption of beef from a local abattoir . During investigation of the abattoir, bovine rectal swabs and samples of meat and surface swabs from beef carcasses were examined for E . coli O157, isolates of which were tested for toxigenicity, plasmid content and phage type . E . coli O157 was isolated from 84 (4%) of 2103 bovine rectal swabs; of these 84, 78 (93%) were VT+, the most common phage types being 2 and 8, the types implicated in the cluster of human cases . Positive cattle were from diverse sources within England . E . coli O157 was isolated from 7 (30%) of 23 carcasses of rectal swab-positive cattle and from 2 (8%) of 25 carcasses of rectal swab-negative cattle . The study has shown that cattle may be a reservoir of VT+ E . coli O157, and that contamination of carcasses during slaughter and processing may be how beef and beef products become contaminated and thereby transmit the organism to man.

Epidemiol Infect, 1993 Dec, 111(3), 429 - 38
Virulence properties of Escherichia coli strains belonging to serogroups O26, O55, O111 and O128 isolated in the United Kingdom in 1991 from patients with diarrhoea; Scotland SM et al.; Some strains of Escherichia coli belonging to serogroups O26, O55, O111 or O128 produce Vero cytotoxin (VT) . These serogroups are included in the range of enteropathogenic E . coli (EPEC) serogroups for which commercial antisera are available . In an attempt to obtain information on VT-producing strains other than those of serogroup O157, 122 strains belonging to these four serogroups and isolated in 1991 from patients with diarrhoea in the United Kingdom were tested for hybridization with VT probes . Only 18 of the 122 strains were VT-positive and these were O26 or O128 . However 90 strains hybridized with the E . coli attaching and effacing (eae) probe (including 14 VT-positive strains) and 17 with the enteroaggregative E . coli (EAggEC) probe . For 78 eae-positive and 9 EAggEC-positive strains, tissue culture tests correlated with the probe results as the strains gave, respectively, either localized adhesion and a positive fluorescent-actin staining test or a characteristic aggregative attachment . A total of 111 of the 122 strains belonging to serogroups O26, O55, O111 or O128 possessed properties that may be associated with the ability to cause human diarrhoeal disease, and similar studies are needed on strains from the other classical EPEC serogroups.

Am J Med Sci, 1993 Dec, 306(6), 398 - 406
Southwestern Internal Medicine Conference: Shiga-like toxins in hemolytic-uremic syndrome and thrombotic thrombocytopenic purpura; Hofmann SL; The majority of cases of hemolytic-uremic syndrome and a smaller proportion of cases of thrombotic thrombocytopenic purpura have recently been shown to result from a toxin produced by enteric bacteria, referred to as verotoxin, or Shiga-like toxin . The predominant toxin-producing bacterial strain in North America is E . coli O157:H7, which causes hemorrhagic colitis in humans after ingestion of contaminated meat . The toxin is believed to gain entry to the circulation from the bowel wall; it then binds to specific glycolipid receptors abundant on renal vascular endothelial cells . The toxin inactivates ribosomes inside the cells, thereby killing them and producing the clinical manifestations of hemolytic-uremic syndrome . Recognition of the etiology of hemolytic-uremic syndrome may lead to better prospects for prevention and treatment.

J Infect, 1993 Nov, 27(3), 237 - 41
Heterogeneity in expression of lipopolysaccharides by strains of Escherichia coli O157; Chart H et al.; A total of 47 strains of Escherichia coli belonging to serogroup O157 were examined for the expression of long-chain lipopolysaccharide (LPS) by means of SDS-PAGE and silver staining . Strains belonged to 10 different flagellar (H) types or did not express flagella . Nine strains carried genes encoding Vero cytotoxin (VT) . Strains of E . coli O157 expressed one of three LPS SDS-PAGE profiles designated A, B and C . Strains expressing profile A belonged to H-types 6 and 19, while those expressing LPS profile B belonged to H-types 2, 16, 20, 39, 42 and 45 . Strains of E . coli expressing profile C belonged to H-types 7 and 8; strains producing VT expressed LPS profile C only, although not all strains with H-types 7 and 8 carried genes for VT . Regardless of H-type or the LPS profile expressed, serum antibodies produced by patients infected with strains of E . coli belonging to serogroup O157 would be detected by serological tests.

Zentralbl Bakteriol, 1993 Nov, 279(4), 512 - 7
A case of laboratory acquired infection with Escherichia coli O157:H7; Burnens AP et al.; A case of laboratory-acquired infection with Escherichia coli O157:H7 is presented . Evidence of the identity of the infecting strain was provided by toxin type and plasmid profiles . Because no obvious technical errors in laboratory practices could be demonstrated we conclude that the infecting dose for E . coli O157:H7 may be small . The clinical course was uncomplicated; during reconvalescence, the patient's serum recognized a unique 87 kDa band on immunoblots of the infecting strain.

J Appl Bacteriol, 1993 Nov, 75(5), 420 - 6
Examination of raw beef products for the presence of Vero cytotoxin producing Escherichia coli, particularly those of serogroup O157; Willshaw GA et al.; Fifty-four of 310 (17%) samples of raw beef products contained Vero cytotoxin (VT)-producing Escherichia coli (VTEC) detected by DNA probes for the VT genes . VTEC strains examined in detail from a selection of the positive samples belonged to several O serogroups, some of which have been associated with human diarrhoea or haemolytic uraemic syndrome . Some of the strains possessed properties that may contribute to virulence in man . None of the food samples contained VT-producing E . coli O157 when tested by a combination of VT probe tests and colony immunoblotting with commercially available anti-O157 serum . Quantification of the immunoblotting technique indicated that O157 VTEC could be recovered from artificially-inoculated meat samples at a level of less than one organism per gram . Five of the food samples carried E . coli O157 strains that did not produce VT and differed in other properties from O157 VTEC.

J Clin Pathol, 1993 Nov, 46(11), 1053 - 4
Patients with haemolytic uraemic syndrome caused by Escherichia coli O157: absence of antibodies to Vero cytotoxin 1 (VT1) or VT2; Chart H et al.; Serum samples from 30 patients with haemolytic uraemic syndrome (HUS), caused by Escherichia coli O157, and 30 apparently healthy volunteers, were used to examine the immune response of patients to Vero cytotoxins (VT) 1 and VT2 . Patients' sera could not be differentiated from control sera using ELISA; and using immunoblotting, none of the sera had antibodies reactive with either the A or B subunits of VT1 or VT2 . Examination of sera for antibodies to VT1 and VT2 seems to be of little value in the serodiagnosis of HUS caused by Vero cytotoxin-producing E coli O157.

J Med Microbiol, 1993 Nov, 39(5), 371 - 81
Studies on Escherichia coli serotype O157:H7 strains containing a 60-MDa plasmid and on 60-MDa plasmid-cured derivatives; Fratamico PM et al.; Seventeen strains of Escherichia coli serotype O157:H7 producing Shiga-like toxin were examined for the presence of plasmids and for the ability to adhere to HEp-2 and Intestine 407 cells . All of the strains possessed a common 60-MDa plasmid . To determine the role of the 60-MDa plasmid, plasmid-cured strains were compared with the parent strains for their ability to produce pili and to adhere to epithelial cells in culture . The total cell lysate protein and outer-membrane protein (OMP) profiles were also compared . Both the parent strains and their plasmid-cured derivatives produced pili . Immunofluorescence assay results indicated that the plasmid-cured and parent strains adhered equally well to HEp-2 and Intestine 407 cells; overall adherence was greater with intestinal cells than HEp-2 cells . SDS-PAGE of polypeptides synthesised in an E . coli system in vitro showed that plasmid DNA encodes c . 35 proteins . SDS-PAGE of OMP preparations demonstrated that the 60-MDa plasmid appears to be involved in the synthesis of a 33-kDa OMP . Two strains cured of the 60-MDa plasmid, one that possessed no plasmids and one that still contained a 2.2-MDa plasmid, produced exopolysaccharide (EPS) when cultured on solid medium at 25 degrees C . Two other strains, which were cured of the 60-MDa plasmid but contained a 4.5-MDa plasmid, did not produce visible amounts of EPS . Gas chromatography analysis showed that the EPS consisted of fucose, glucose and galactose in an approximate molar ratio of 2.0:0.9:1.1 and also had 7% of a uronic acid sugar as part of its structure.

Infect Immun, 1993 Oct, 61(10), 4085 - 92
Expression and characterization of the eaeA gene product of Escherichia coli serotype O157:H7; Louie M et al.; In enteropathogenic Escherichia coli, the eaeA gene produces a 94-kDa outer membrane protein called intimin which has been shown to be necessary but not sufficient to produce the attaching-and-effacing lesion . The purpose of this study was to characterize the intimin specified by the eaeA allele of the enterohemorrhagic E . coli (EHEC) serotype O157:H7 strain CL8 and to determine its role in adherence . The carboxyl-terminal 266 amino acids of the CL8 intimin were expressed as a protein fusion with glutathione S-transferase, which was used to raise antiserum in rabbits . The antiserum reacted in Western immunoblots with a 97-kDa outer membrane protein of EHEC strains of serogroups O5, O26, O111, and O157 and enteropathogenic E . coli strains of serogroups O55 and O127 . Surface labelling of CL8 with 125I showed that intimin was surface exposed . An eaeA insertional inactivation mutant of CL8 was produced and was designated CL8-KO1 . Total adherence of CL8-KO1 to HEp-2 cells was not significantly different from that of CL8, but CL8-KO1 gave a negative result in the fluorescent actin staining test . The eaeA gene expressed alone in E . coli HB101 also gave a negative fluorescent actin staining test result . The eaeA gene of CL8 was able to complement the eaeA deletion mutation in CVD206 . We conclude that the product of the EHEC eaeA gene is a 97-kDa surface-exposed protein and propose that it be designated intiminO157 . Sherman et al . described a 94-kDa outer membrane protein which played an important role in adherence of E . coli O157:H7 (Infect . Immun . 59:890-899, 1991) . Western immunoblotting and indirect fluorescent antibody studies showed that the protein described by Sherman et al . is not intimin.

Curr Opin Pediatr, 1993 Oct, 5(5), 573 - 9
Gastrointestinal infection in children; Lewis LG et al.; Infections of the gastrointestinal tract remain an important cause of childhood morbidity and mortality worldwide . A number of pertinent articles have appeared in the past year, advancing our understanding of 1) Helicobacter pylori-induced gastroduodenal disease, 2) Escherichia coli O157:H7-mediated diarrhea, and 3) newer gastrointestinal parasites that cause diarrhea . These are the topics of review.

J Clin Microbiol, 1993 Oct, 31(10), 2799 - 801
Profile of Escherichia coli O157:H7 pathogen responsible for hamburger-borne outbreak of hemorrhagic colitis and hemolytic uremic syndrome in Washington; O'Brien AD et al.; We analyzed Escherichia coli O157:H7 isolates from stool samples of five patients who had bloody diarrhea and were infected during a large food-borne outbreak of hemorrhagic colitis in Washington state . The isolates were assessed for Shiga-like toxin profile, adherence and plasmid traits, mouse virulence, capsule, and enterohemolysin production . The profiles of the five isolates were indistinguishable from each other and similar to that of E . coli O157:H7 strain EDL933, an organism responsible for a similar hamburger-associated food poisoning episode in 1982.

J Clin Invest, 1993 Sep, 92(3), 1418 - 24
The role of the eae gene of enterohemorrhagic Escherichia coli in intimate attachment in vitro and in a porcine model; Donnenberg MS et al.; The eaeA gene of enteropathogenic Escherichia coli (EPEC) is necessary for intimate attachment to epithelial cells in vitro . Enterohemorrhagic E . coli (EHEC) strains also possess an eae gene and are capable of intimate attachment and microvillus effacement in vitro and in animal models . To assess the role of the EHEC eae gene in intimate attachment, we constructed an eae deletion/insertion mutation in wild-type EHEC O157:H7 strain 86-24 by using linear electroporation of a recombinant allele . The mutant obtained was deficient in inducing f-actin accumulation in HEp-2 cells and was incapable of attaching intimately to colonic epithelial cells in a newborn piglet model of infection . Intimate attachment in vivo was restored when the EHEC eae gene or the eaeA gene of EPEC was introduced into the mutant on a plasmid . These results indicate that the eae gene is necessary for intimate attachment of EHEC in vivo . In addition, the complementation achieved by the EPEC locus indicates that the eae gene of EHEC and the eaeA gene of EPEC are functionally homologous.

Am J Vet Res, 1993 Sep, 54(9), 1446 - 51
Enterotoxigenic, verotoxigenic, and necrotoxigenic Escherichia coli isolated from cattle in Spain; Blanco M et al.; To assess the role of enterotoxigenic (ETEC), verotoxigenic (VTEC), and necrotoxigenic (NTEC) Escherichia coli in cattle with diarrhea, 1,524 colonies of E coli isolated from 197 calves with diarrhea and from 112 healthy controls were investigated for production of heat-labile and heat-stable enterotoxins, verotoxins, and cytotoxic necrotizing factors (CNF1 and CNF2) . The ETEC were isolated from only 2 (1%) calves with diarrhea and from 5 (4%) healthy controls . In contrast, VTEC and NTEC that produced CNF2 were frequently identified . The VTEC were isolated from 18 (9%) calves with diarrhea and from 21 (19%) healthy cattle (P < 0.05), whereas NTEC that produced CNF2 were detected in 39 (20%) ill calves and in 38 (34%) controls (P < 0.01) . Therefore, VTEC and NTEC that produced CNF2 were isolated significantly more frequently from healthy than diseased calves . Serogroups to which VTEC belonged differed considerably from the O groups involved with NTEC . Although, VTEC belonged to 18 serogroups, only 4 (O26, O103, O113, and O157) accounted for 56% (25 of 45) of verotoxigenic strains . The NTEC that produced CNF2 belonged to 26 serogroups; however, 64% (69 of 108) were from 6 serogroups (O1, O3, O15, O55, O88, and O123) . Our results are compatible with cattle being a reservoir of VTEC that are pathogenic for human beings and with ETEC being an unusual cause of bovine colibacillosis in Galicia (northwestern Spain) . Furthermore, results of this study indicate that VTEC and NTEC that produced CNF2 may be part of the normal intestinal flora of cattle.

Appl Environ Microbiol, 1993 Sep, 59(9), 3141 - 4
Comparison and genomic sizing of Escherichia coli O157:H7 isolates by pulsed-field gel electrophoresis; Harsono KD et al.; Genomic DNAs of Escherichia coli O157:H7 strains isolated from patients and food samples were analyzed by pulsed-field gel electrophoresis . The rare-cutting endonucleases SfiI and XbaI generated 6 and 10 distinct genomic profiles, respectively, for the 22 strains analyzed, indicating that this technique may find application for epidemiologic studies . Summation of XbaI fragments from five E . coli O157:H7 strains estimated the genomic length at ca . 4.7 Mb.

Eur J Clin Microbiol Infect Dis, 1993 Sep, 12(9), 707 - 9
Serological detection of verocytotoxin-producing Escherichia coli in patients with haemolytic uraemic syndrome in western Europe; Chart H et al.; Sera from 45 patients from The Netherlands, Germany and Belgium who had a clinical diagnosis of haemolytic uraemic syndrome (HUS) were screened for antibodies to the lipopolysaccharide (LPS) of Escherichia coli producing Verocytotoxin (VTEC) . Sera from 43 family contacts and 34 control patients were also examined . Using the techniques of EIA and immunoblotting, antibodies to the LPS of Escherichia coli O157 were found in 28 patients, and to the LPS of serogroups O115 and O145 in one patient and one family member respectively . The results of our study suggest that VTEC, and in particular Escherichia coli O157, might be a significant cause of HUS in Western Europe.

Appl Environ Microbiol, 1993 Aug, 59(8), 2364 - 8
Survival and growth of Escherichia coli O157:H7 in ground, roasted beef as affected by pH, acidulants, and temperature; Abdul-Raouf UM et al.; A study was undertaken to determine the fate of Escherichia coli O157:H7 in ground, roasted beef as influenced by the combined effects of pH, acidulants, temperature, and time . There was essentially no change in the viable population of E . coli O157:H7 when beef salads (pH 5.40 to 6.07) containing up to 40% mayonnaise were incubated at 5 degrees C for up to 72 h . At 21 and 30 degrees C, significant (P < or = 0.05) increases in populations of the organism occurred in salads containing 16 to 32% mayonnaise (pH 5.94 to 5.55) between 10 and 24 h of incubation . Death was more rapid as the pH of acidified beef slurries incubated at 5 degrees C was decreased from 5.98 to 4.70 . E . coli O157:H7 grew in control slurries (pH 5.98) and in slurries containing citric and lactic acids (pHs 5.00 and 5.40) incubated at 21 degrees C for 24 h; decreases occurred in slurries acidified to pHs 4.70, 5.00, and 5.40 with acetic acid or pH 4.70 with citric or lactic acid . At 30 degrees C, populations decreased in slurries acidified to pHs 4.70 and 5.00 with acetic acid . Citric and lactic acids failed to prevent significant increases in populations in slurries at pH 4.70 to 5.40 between 10 and 24 h of incubation . The order of effectiveness of acidulants in inhibiting growth was acetic acid > lactic acid > or = citric acid . The same order was observed for inactivation of E . coli O157:H7 in acidified (pH 5.00) beef slurry heated at 54 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)

JAMA, 1993 May 5, 269(17), 2217 - 20
An outbreak of diarrhea and hemolytic uremic syndrome from Escherichia coli O157:H7 in fresh-pressed apple cider; Besser RE et al.; OBJECTIVE--Escherichia coli O157:H7 causes hemorrhagic colitis and the hemolytic uremic syndrome . In the fall of 1991, an outbreak of E coli O157:H7 infections in southeastern Massachusetts provided an opportunity to identify transmission by a seemingly unlikely vehicle . DESIGN--Case-control study to determine the vehicle of infection . New England cider producers were surveyed to assess production practices and determined the survival time of E coli O157:H7 organisms in apple cider . RESULTS--Illness was significantly associated with drinking one brand of apple cider . Thirteen (72%) of 18 patients but only 16 (33%) of 49 controls reported drinking apple cider in the week before illness began (odds ratio {OR}, 8.3; 95% confidence interval {CI}, 1.8 to 39.7) . Among those who drank cider, 12 (92%) of 13 patients compared with two (13%) of 16 controls drank cider from cider mill A (lower 95% CI, 2.9; P < .01) . This mill pressed cider in a manner similar to that used by other small cider producers: apples were not washed, cider was not pasteurized, and no preservatives were added . In the laboratory, E coli O157:H7 organisms survived for 20 days in unpreserved refrigerated apple cider . Addition of sodium benzoate 0.1% reduced survival to less than 7 days . CONCLUSIONS--Fresh-pressed, unpreserved apple cider can transmit E coli O157:H7 organisms, which cause severe infections . Risk of transmission can be reduced by washing and brushing apples before pressing, and preserving cider with sodium benzoate . Consumers can reduce their risk by only drinking cider made from apples that have been washed and brushed.

J Clin Microbiol, 1993 May, 31(5), 1268 - 74
Detection and characterization of the eae gene of Shiga-like toxin-producing Escherichia coli using polymerase chain reaction; Gannon VP et al.; In this study, the polymerase chain reaction (PCR) was used in the detection of the attaching and effacing (eae) gene of Shiga-like toxin-producing Escherichia coli (SLT-EC) . Oligonucleotide primers, complementary to the 5' portion of the eae gene of the enteropathogenic E . coli E2348/69 (O127:H6) and of SLT-EC CL8 and EDL933 (O157:H7), generated PCR products of the predicted sizes with DNA from the majority of human clinical SLT-EC strains tested from O serogroups 5, 26, 103, 111, 121, 128, 145, and 157; all SLT-EC strains of O serogroups 5, 26, and 111 from cattle; and a minority of porcine SLT-EC strains (one strain each from O serogroups 107 and 130 and one rough strain) . Five HaeIII digestion profiles were obtained for PCR products generated by amplification of a 2.3-kb DNA fragment from the 5' end of eae . The HaeIII profiles for SLT-EC O serogroups, such as 26, 103, and 157, differed from each other but were consistent among strains within these O serogroups . Oligonucleotide primer pairs complementary to the 3' end of either the O127:H6 E . coli or the O157:H7 eae nucleotide sequence only amplified DNA from E . coli strains from a few of the SLT-EC O serogroups examined . One primer pair with homology to the 3' nucleotide sequence of eae from E . coli O157:H7 appeared to be relatively specific for this O serogroup by PCR . No PCR products were obtained in amplification experiments with the eae primers using DNA from human SLT-EC of O serogroups 38 (1 0f 1) and 91 (3 or 3), 15 of 15 SLT-EC strains from edema disease, or 29 of 29 non-SLT-EC strains from pigs and calves with diarrhea.

J Appl Bacteriol, 1993 May, 74(5), 557 - 63
Intestinal colonization of young chicks with Escherichia coli O157:H7 and other verotoxin-producing serotypes; Stavric S et al.; The susceptibility of chicks to colonization with Escherichia coli O157:H7 and other verotoxin-producing serotypes was studied . The E . coli colonized the caeca of both broilers and layers after oral administration of the challenge . The extent of colonization was dependent on challenge dose, age of chicks at the time of challenge, breed of chicks and length of time after exposure . A rapid increase in caecal colonization and a decrease in crop colonization was evident during the first few hours after challenge, with a maximum in the caeca at 6 h . Escherichia coli persisted in caecal contents as well as on caecal walls throughout the course of the experiments (14 d), but at much lower levels compared with the 6 h post-challenge.

Infection, 1993 May-Jun, 21(3), 140 - 5
Differences in verotoxin neutralizing activity of therapeutic immunoglobulins and sera from healthy controls; Bitzan M et al.; Intestinal infection by Escherichia coli O157 and other verotoxin (VT) producing E . coli has been increasingly recognized as an important factor for the causation of classic (enteropathic) hemolytic uremic syndrome (HUS) and hemorrhagic colitis (HC) . Toxins most frequently involved are VT1 and VT2 . As with other toxin-mediated diseases, administration of immunoglobulin (Ig) may be beneficial . However, little is known about the immune response elicited by the toxin(s), and the prevalence of VT neutralizing antibodies in the healthy population . We studied the capacity of seven Igs and a commercial plasma preparation to neutralize four different VTs (VT1, VT2, VT2c and VT2e) . The results were compared with the neutralization titers (NT50%) of normal human serum samples from various age groups . Plasma products and normal sera were separated by protein G affinity chromatography to investigate the factor(s) responsible for VT neutralization . All Igs neutralized VT1 (8 to 96 NT50%) . None of them inhibited VT2, VT2c or VT2e effectively . In contrast, none of 40 pediatric, and only one of 20 adult control sera (starting dilution 1:4) neutralized VT1 (25 NT50%) . All 60 samples as well as the plasma preparation blocked VT2 (22 to 446 NT50%, median 137), but not VT2c and VT2e . The VT1 neutralizing activity was eluted with the IgG fraction . The VT2 neutralizing activity was not bound by protein G, but was recovered in the IgG-free effluent . In conclusion, therapeutic Igs significantly neutralize VT1, but are largely ineffective against other VTs . In contrast, all control sera inhibited VT2, but rarely VT1.(ABSTRACT TRUNCATED AT 250 WORDS)

Infect Immun, 1993 May, 61(5), 1619 - 29
Clonal relationships among Escherichia coli strains that cause hemorrhagic colitis and infantile diarrhea; Whittam TS et al.; The genetic relationships among 1,300 isolates of Escherichia coli representing 16 serotypes associated with enteric disease, including O157:H7 strains recovered from patients with hemorrhagic colitis and hemolytic uremic syndrome and O26:H11, O55:H6, O55:H7, O111:H2, and O128:H2 strains, many of which were isolated originally from infants with diarrhea, were estimated from allelic variation among 20 enzyme-encoding genes detected by multilocus enzyme electrophoresis . Multiple electrophoretic types were observed among isolates of each serotype, with isolates of the same O serogroup differing on average at 28% of the enzyme loci . Comparisons of the multilocus enzyme profiles revealed that 72% of the isolates belong to 15 major electrophoretic types, each of which corresponds to a bacterial clone with a wide geographic distribution . Genetically, the O157:H7 clone is most closely related to a clone of O55:H7 strains that has long been associated with worldwide outbreaks of infantile diarrhea . We propose that the new pathogen emerged when an O55:H7-like progenitor, already possessing a mechanism for adherence to intestinal cells, acquired secondary virulence factors (Shiga-like cytotoxins and plasmid-encoded adhesins) via horizontal transfer and recombination.

MMWR Morb Mortal Wkly Rep, 1993 Apr 16, 42(14), 258 - 63
Update: multistate outbreak of Escherichia coli O157:H7 infections from hamburgers--western United States, 1992-1993; Elimination of Escherichia coli O157:H7 in meats by gamma irradiation; Food Safety Research Unit, Eastern Regional Research Center, USDA Agricultural Research Service, Philadelphia, Pennsylvania 19118Undercooked and raw meat has been linked to outbreaks of hemorrhagic diarrhea due to the presence of Escherichia coli O157:H7; therefore, treatment with ionizing radiation was investigated as a potential method for the elimination of this organism . Response-surface methods were used to study the effects of irradiation dose (0 to 2.0 kGy), temperature (-20 to +20 degrees C), and atmosphere (air and vacuum) on E . coli O157:H7 in mechanically deboned chicken meat . Differences in irradiation dose and temperature significantly affected the results . Ninety percent of the viable E . coli in chicken meat was eliminated by doses of 0.27 kGy at +5 degrees C and 0.42 kGy at -5 degrees C . Small, but significant, differences in radiation resistance by E . coli were found when finely ground lean beef rather than chicken was the substrate . Unlike nonirradiated samples, no measurable verotoxin was found in finely ground lean beef which had been inoculated with 10(4.8) CFU of E . coli O157:H7 per g, irradiated at a minimum dose of 1.5 kGy, and temperature abused at 35 degrees C for 20 h . Irradiation is an effective method to control this food-borne pathogen.

Mol Cell Probes, 1993 Apr, 7(2), 151 - 4
Identification of Escherichia coli serotype O157:H7 by DNA probe specific for an allele of uid A gene; Feng P; Isolates of Escherichia coli serotype O157:H7 were identified by an oligonucleotide probe, PF-27, containing a unique base substitution in the allele of the uid A gene . Colony hybridization analysis of 239 bacteria, including E . coli, Shiga-like toxin-producing serogroups of pathogenic E . coli and other enteric isolates showed that the probe reacted only with isolates of serotype O157:H7 . Results of genetic analyses suggest that the base substitution in the allele does not contribute to the absence of uid A gene expression in O157:H7.

JAMA, 1993 Feb 17, 269(7), 883 - 8
Transmission of Escherichia coli O157:H7 infection in Minnesota child day-care facilities; Belongia EA et al.; OBJECTIVE--Escherichia coli O157:H7 infection can cause hemorrhagic colitis and hemolytic uremic syndrome . Since 1988 the Minnesota Department of Health has carried out surveillance for this infection . To assess the occurrence of person-to-person transmission within day-care facilities, we investigated facilities where an infected child attended after onset of symptoms . DESIGN--Parents of children less than 5 years old with E coli O157:H7 infection were interviewed from July 1988 through December 1989 . If the child attended day care after onset, stool cultures were obtained from other children in attendance and their parents were interviewed . If there was presumptive evidence of ongoing E coli O157:H7 transmission in a facility, all preschool children were excluded from attending day-care facilities until two consecutive stool cultures were negative . RESULTS--Sixty-eight cases of E coli O157:H7 infection were identified in Minnesota during the 18-month period, including 29 cases identified through investigations at nine day-care facilities . There was evidence of person-to-person transmission in all nine facilities . The median number of infected children per facility was two (range, two to 18), and the median attack rate was 22% (range, 3% to 38%) . The median age of the primary case at each facility was 26 months (range, 12 to 59 months) . There was no evidence of further transmission at facilities where children were temporarily excluded until two consecutive stool cultures were negative . CONCLUSION--Person-to-person transmission of E coli O157:H7 is common when infected preschool children attend day care while symptomatic . The number of unrecognized day-care outbreaks in the United States may be substantial due to the lack of routine testing for this pathogen in stool cultures, the absence of public health surveillance in many regions, and incomplete follow-up of infected children . Temporary exclusion of all children was an effective control strategy in this population, but additional investigations are needed to determine the optimal intervention.

Kansenshogaku Zasshi, 1993 Feb, 67(2), 122 - 6
{Epidemiology of sporadic pediatric enteritis patients due to verotoxin-producing Escherichia coli}; Morooka T et al.; We tried to isolate verotoxin-producing Escherichia coli (VTEC) from 323 sporadic pediatric enteritis patients who came to three clinics in the Fukuoka area . We used the sorbitol-MacConkey medium for the isolation of VTEC O157:H7 . For non-O157 VTEC strains we used the V1/PECS method . VT/PECS method was applied . VTEC strains were isolated from three patients (0.9%) . None of the patients were seriously, ill or developed the hemolytic uremic syndrome . The three patients were all seen in the summer season, July and August . O157:H7 strains were isolated from two patients, and O145:NM from one . This study showed that sporadic enteritis cases due to VTEC exist in the Fukuoka area . In the future a rapid and easy method for the detection of VT or VTEC should be developed and commercialized to proceed with epidemiological studies of VTEC infections throughout Japan.

Gastroenterology, 1993 Feb, 104(2), 467 - 74
The effect of enterohemorrhagic Escherichia coli O157:H7 on intestinal structure and solute transport in rabbits; Li Z et al.; BACKGROUND: The effect of enterohemorrhagic Escherichia coli O157:H7 infection on intestinal morphology and solute transport was examined . METHODS: New Zealand white rabbits, aged 10 days, were infected with E . coli strain EDL933 (O157:H7 containing the 60-megadalton plasmid-encoding adhesion factors VT1 and VT2) and compared with controls . Small and large intestinal histology and solute transport were studied 5 days after inoculation . Ion transport in the distal colon was also examined in animals infected with different strains encoding a combination of pathogenic factors . RESULTS: Infection with EDL933 induced diarrhea and mucosal disease in the colon, inhibited colonic Na+ absorption, and stimulated of Cl- secretion, but had no impact on the small intestine . Infection with strains A7785-C3A (O157:H7, plasmid-, VT1+, VT2+) and 85-170 (O157:H7, plasmid+, VT-) induced similar transport changes to EDL933 . C600/1 (E . coli K-12, plasmid+, VT1+) decreased Na+ and Cl- absorption only . CONCLUSIONS: Abnormalities of colonic structure and ion transport could account for diarrhea production, but pathogenic factors other than the 60-megadalton plasmid-encoding adhesion factor and verotoxins appear to be involved in enterohemorrhagic E . coli infection.

Nippon Rinsho, 1993 Jan, 51(1), 198 - 203
{Hemolytic uremic syndrome associated with entero-hemorrhagic Escherichia coli}; Takeda T; In 1983, Karmali et al . reported the association between idiopathic HUS with verotoxin producing Escherichia coli (VTEC), and their findings have now been confirmed by numerous other investigators . Recently developed serodiagnosis for VTEC infection is quite useful, and we found that out of 71 patients with HUS, 40 were positive for the antibody against O157 E . coli LPS . 0111 and 026 E . coli were also implicated as etiologic agents in HUS of Japan.

Appl Environ Microbiol, 1992 Dec, 58(12), 3809 - 15
Rapid and sensitive method for detection of Shiga-like toxin-producing Escherichia coli in ground beef using the polymerase chain reaction; Gannon VP et al.; A rapid and sensitive method for detection of Shiga-like toxin (SLT)-producing Escherichia coli (SLT-EC) with the polymerase chain reaction (PCR) is described . Two pairs of oligonucleotide primers homologous to SLTI and SLTII genes, respectively, were used in multiplex PCR assays . The first pair generated a ca . 600-bp PCR product with DNA from all SLTI-producing E . coli tested but not from E . coli strains that produce SLTII or variants of SLTII . The second pair generated a ca . 800-bp PCR product with DNA from E . coli strains that produce SLTII or variants of SLTII but not from SLTI-producing E . coli . When used in combination, the SLTI and SLTII oligonucleotide primers amplified DNA from all of the SLT-EC tested . No PCR products were obtained with SLT primers with DNA from 28 E . coli strains that do not produce SLT or 44 strains of 28 other bacterial species . When ground beef samples were inoculated with SLT-EC strains 319 (O157:H7; SLTI and SLTII), H30 (O26:H11; SLTI), and B2F1/3 (O91:H21; SLTII variants VT2ha and VT2hb) and cultured in modified Trypticase soy broth for 6 h at 42 degrees C, an initial sample inoculum of as few as 1 CFU of these SLT-EC strains per g could be detected in PCR assays with DNA extracted from the broth cultures.

Can Assoc Radiol J, 1992 Dec, 43(6), 451 - 3
Hemorrhagic colitis caused by Escherichia coli O157:H7--unusual ultrasonographic and computed tomography findings; Preiksaitis HG et al.; Hemorrhagic colitis due to Escherichia coli O157:H7 occurs sporadically but widely throughout North America . Radiographically this condition may mimic ischemic colitis, inflammatory bowel disease, acute appendicitis or appendiceal abscess . Correlation of radiologic and clinical findings is required to ensure diagnostic accuracy and avoid unnecessary surgical intervention.

J Med Microbiol, 1992 Nov, 37(5), 304 - 9
The adherence of verocytotoxin-producing Escherichia coli to rabbit intestinal cells; Ashkenazi S et al.; Verocytotoxin-producing Escherichia coli (VTEC) have been recognised recently as an important cause of human disease . The adherence of VTEC to rabbit intestinal tract and the relationship between adherence and other virulence traits were studied . Twenty clinical isolates of VTEC (O157:H7 and other serotypes) and a control, commensal E . coli strain, were examined . Bacteria were evaluated for the presence of surface fimbriae, plasmid profile and hybridisation with a 3.4 kb DNA probe derived from the 60-MDa plasmid of such strains . Adherence was determined by electronmicroscopy and quantitatively with radio-labelled bacteria . Of the VTEC strains, 12 (60%) had surface fimbriae; all O157:H7 and 10 (70%) of 14 of the non-O157:H7 strains hybridised with the probe . No isolate was negative for both of these virulence traits and there was no correlation between their presence . The plasmid profiles varied among the strains, with no correlation to virulence traits . The adherence of VTEC strains differed significantly, ranging from 0.3 to 34.0 bacteria/intestinal cell . The mean adherence of fimbriate strains was greater than that of non-fimbriate strains (3.9 versus 2.7 bacteria/cell), although marked variability was noted in both groups . This study showed that VTEC strains differed markedly in their adherence capability and that neither the presence of fimbriae nor hybridisation with the 3.4-kb probe was essential for adherence . Several distinct mechanisms probably play a role in VTEC adherence.

J Infect Dis, 1992 Oct, 166(4), 797 - 802
Properties of Vero cytotoxin-producing Escherichia coli of human origin of O serogroups other than O157; Willshaw GA et al.; The 48 Vero cytotoxin-producing Escherichia coli (VTEC) examined for properties associated with virulence were of human origin and represented 17 O serogroups other than O157 and O26 . Only Vero cytotoxin production was common to all the strains . About 60% produced enterohemolysin and hybridized with the CVD419 probe derived from plasmid sequences of E . coli O157 . Thirteen strains gave localized adherence (LA) to HEp-2 cells . All of these hybridized with the E . coli attaching and effacing (eae) gene probe and were positive in the fluorescence actin staining test, properties characteristic of strains that efface intestinal microvilli . A further 5 strains were eae probe-positive but did not give LA . None of the VTEC hybridized with a probe specific for the enteropathogenic E . coli adherence factor . Seven strains adhered to HEp-2 cells in a diffuse or aggregative pattern but did not hybridize with probes for these phenotypes . Non-O157 E . coli strains are diverse in their properties, although some may share virulence mechanisms with other diarrheogenic E . coli.

Vet Microbiol, 1992 Sep, 32(2), 163 - 75
Colonization factor different from K88, K99, F41 and 987P in enterotoxigenic Escherichia coli strains isolated from postweaning diarrhoea in pigs; Salajka E et al.; A novel common colonization factor was detected in enterotoxigenic strains of Escherichia coli isolated from intestinal contents of piglets affected with postweaning diarrhoea . This factor was antigenically distinct from the previously described K88, K99, F41, 987P, CFAI, CFAII and Att25 fimbrial antigens . E . coli strains possessing this factor adhered to the pig intestinal brush borders and one strain, used in experimental infection in weanlings, colonized the intestinal epithelium and induced diarrhoea . Examination of 212 toxigenic strains of E . coli isolated from weanlings revealed the presence of the novel common colonization factor in 83 strains, belonging to serogroups O25, O108, O138, O141, O147 and O157 . The antigen K88 was detected in 47 strains belonging to serogroups O8, O141, O147 and O149.

J Clin Microbiol, 1992 Aug, 30(8), 2169 - 72
DNA fingerprinting of Escherichia coli O157:H7 strains by pulsed-field gel electrophoresis; Bohm H et al.; Pulsed-field gel electrophoresis of genomic DNA was carried out on Escherichia coli O157:H7 strains from different geographic locations to determine its value in an epidemiological survey of O157 infections . Pulsed-field gel electrophoresis of XbaI-digested DNA fragments clearly separated E . coli O157:H7 strains from nontoxigenic E . coli O157:H19, O157:H43, and O157:H45 strains and from Shiga-like-toxin-producing E . coli strains of other serogroups . However, among the E . coli O157:H7 strains, the restriction patterns either were identical or differed only by a few fragment bands . In some cases, it was therefore impossible to distinguish among epidemiologically unrelated strains . Hybridization experiments with a DNA probe complementary to Shiga-like toxin II sequences revealed that the Shiga-like toxin II genes were located on DNA fragments of different lengths . Our data show that for a single highly conserved clone, such as E . coli O157:H7, other typing techniques may need to be performed in addition to DNA fingerprinting in epidemiological surveys.

J Clin Microbiol, 1992 Aug, 30(8), 2153 - 7
Enterohemorrhagic Escherichia coli associated with hemolytic-uremic syndrome in Chilean children; Cordovez A et al.; A clinicoepidemiological study was undertaken to determine if enterohemorrhagic Escherichia coli (EHEC) was associated with hemolytic-uremic syndrome (HUS) in children in Santiago, Valdivia, and Temuco, Chile . Prospective surveillance detected 20 hospitalized cases of HUS in children less than 4 years of age in these cities from March 1988 to March 1989 . Each HUS patient was matched (by sex and age) with two control children (hospitalized elective-surgery patients) . To detect EHEC, DNA from stool culture isolates of E . coli was detected by hybridization with biotin-labelled DNA probes specific for the EHEC virulence plasmid, Shiga-like toxin I (SLT-I) or SLT-II . Stool cultures from 6 of 20 cases (30%) and from 2 of 38 controls (5.3%) yielded EHEC (P = 0.0158) . EHEC isolates from all HUS cases hybridized with the EHEC plasmid probe and with probes for SLT-I or -II (or both) . The serogroups of the isolates included O157, O26, and O111 . EHEC causes HUS in Chile, and the biotinylated gene probes are practical diagnostic tools for epidemiologic studies.

J Lab Clin Med, 1992 Aug, 120(2), 229 - 38
Verotoxin glycolipid receptors determine the localization of microangiopathic process in rabbits given verotoxin-1; Zoja C et al.; Infection with verotoxin-producing Escherichia coli has been implicated in the cause of hemolytic-uremic syndrome . Cases of thrombotic thrombocytopenic purpura and verotoxin infections have been also described . In this study we sought to determine the following: (1) whether verotoxin induces microvascular lesions in the rabbit, (2) the organ distribution of such lesions, and (3) the distribution of verotoxin glycolipid receptors in the various organs . Rabbits challenged with verotoxin-1 purified from E . coli O157:H7 had anorexia, lethargia, and limb paralysis; renal function, however, was normal . Central nervous system lesions found included pericellular and perivascular edema, focal hemorrhage, vascular lesions, and severe alterations of Purkinje cells . Histologic changes were also seen in the colon, with mucosal and submucosal edema and hemorrhage, and in the lung, with interstitial fibrosis and focal lymphohistiocitic infiltration . No lesions were detected in kidney, heart, liver, and spleen . Screening of various tissues for the presence of the verotoxin receptors revealed galabiosyl ceramide in the central nervous system and globotriosyl ceramide in the gastrointestinal tract, lung, and spleen . No receptors for verotoxin were found in the heart, liver, and kidney . These results indicate that organ localization of the disease in rabbits is dependent on the distribution of verotoxin receptors.

Eur J Clin Microbiol Infect Dis, 1992 Jul, 11(7), 631 - 4
Occurrence and phenotypic properties of verotoxin producing Escherichia coli in sporadic cases of gastroenteritis; Burnens AP et al.; Five verotoxin producing Escherichia coli strains were detected in 405 patients with infectious gastroenteritis and 3 such strains were detected in 11 patients with the hemolytic uremic syndrome in Switzerland . Production of verotoxin 2 was associated with the latter three strains . Four strains reacted with the probe for the virulence plasmid of Escherichia coli O157:H7, and six reacted with a recently described probe for the eae gene of enteropathogenic Escherichia coli . None of the strains was of serotype O157:H7 . The methods available at present for detecting toxins or toxin genes will reliably detect all such verotoxin producing strains.

Curr Microbiol, 1992 Jul, 25(1), 9 - 17
Demonstration of exopolysaccharide production by enterohemorrhagic Escherichia coli; Junkins AD et al.; Enterohemorrhagic Escherichia coli O157:H7 produces visibly slimy colonies when grown on Sorbitol/MacConkey or Maloney's agar plates at room temperature, indicative of exopolysaccharide (EPS) production . Eighteen of 27 (67%) wild-type E . coli O157:H7 isolates produced enough EPS to be visually distinguishable . Of five strains that showed no visible EPS production on these media, four (80%) did produce slimy colonies on media containing higher salt concentrations . Measurements of EPS production by colorimetric determination of uronic acid indicated that EPS production was affected by growth temperature, atmosphere, and medium . Wild-type E . coli O157:H7 strain 932 produced the greatest amounts of EPS when grown anaerobically at 37 degrees C, whereas its plasmid-cured derivative 932P produced large quantities of EPS when grown aerobically at room temperature . Electron micrographs revealed thin, flexible fibers extending from the bacterial cell surface . Cells of strain 932P grown aerobically at room temperature were completely encased in a thick EPS matrix . Chemical analysis of purified EPS revealed that it is very similar or identical to colanic acid . E . coli O157:H7 adheres better to INT 407 cells when grown under conditions that favor high EPS production than when grown under conditions that repress EPS production.

Vet Pathol, 1992 May, 29(3), 239 - 46
Colonization of the small intestine of weaned pigs by enterotoxigenic Escherichia coli that lack known colonization factors; Nagy B et al.; Intestinal colonization of 3-week-old weaned pigs by enterotoxigenic Escherichia coli (ETEC) strains that were originally isolated from weaned pigs with fatal diarrhea and that lacked K88, K99, F41, and 987P adhesins (4P- ETEC) was studied by histologic, immunofluorescent, and electron microscopic techniques . In the first experiment, 16 principal pigs were inoculated orogastrically with ETEC strain 2134 (serogroup O157: H19) or 2171 (serogroup 0141:H4), and eight control pigs were not inoculated . In the second experiment, 24 principals were inoculated with ETEC strain 2134, and 12 controls were inoculated with a nonenterotoxigenic strain of E . coli . Principal and control pigs were necropsied at intervals from 24 to 72 hours after inoculation of principals to provide the tissues used for this report . Results from the two experiments and with both ETEC strains were similar and therefore were combined . Adhesion by 4P- ETEC was demonstrated in ileum but not in cecum or colon in 22/40 principal pigs sampled at 24 to 72 hours after orogastric inoculation . Adherent bacteria were most apparent on the intestinal villi covering Peyer's patches . Only occasional adherent bacteria were detected in ileal sections from a few (4/20) of the control pigs . Adherence by 4P- ETEC was characterized by "patches" of bacteria closely associated with the lateral surfaces and less frequently with the tips and the bases of intact villi . In most cases, the adherent bacteria were separated from epithelial cell microvilli and other bacterial cells by a 50-400-nm space . Filamentous bacterial appendages bridged this space and formed a network among adjacent bacteria.(ABSTRACT TRUNCATED AT 250 WORDS)

J Infect, 1992 May, 24(3), 257 - 61
Improved detection of infection by Escherichia coli O157 in patients with haemolytic uraemic syndrome by means of IgA antibodies to lipopolysaccharide; Chart H et al.; Samples of serum from 125 patients with haemolytic uraemic syndrome, were screened for antibodies of the IgA and IgM classes to the lipopolysaccharide (LPS) of Escherichia coli O157:H7 . By means of the techniques of ELISA and immunoblotting, 48 samples were shown to contain antibodies of the IgM class to E . coli O157 LPS, while 42 samples contained IgA antibodies to this O-antigen . Thirteen patients produced IgM but not IgA antibodies to the LPS of E . coli O157:H7 . Of 42 patients with IgA antibodies to the E . coli O157 LPS, seven did not produce antibodies of the IgM class . From this study, screening patients' serum for antibodies to E . coli O157 LPS of the IgA class, in addition to those of the IgM class, a total of 55 patients were shown to be seropositive . This constituted an increase is in the sensitivity of obtaining evidence of infection by this organism by 12%.

J Clin Microbiol, 1992 May, 30(5), 1315 - 6
Serological cross-reactions between Escherichia coli O157 and other species of the genus Escherichia; Rice EW et al.; The antigenic relatedness of Escherichia coli O157 and four sorbitol-negative species of the genus Escherichia was examined . Isolates of Escherichia hermannii, E . fergusonii, E . vulneris, and E . blattae were tested in the tube agglutination assay by using polyclonal antisera and in the slide agglutination assay by using latex reagents . Only four isolates (17%) of E . hermannii exhibited serological cross-reactivity.

J Clin Microbiol, 1992 May, 30(5), 1174 - 8
Indirect hemagglutination assay for diagnosis of Escherichia coli O157 infection in patients with hemolytic-uremic syndrome; Bitzan M et al.; An indirect hemagglutination assay consisting of sheep erythrocytes coated with lipopolysaccharide (LPS) from Shiga-like toxin-producing Escherichia coli O157 was used for the serological diagnosis of E . coli O157 infections in children with classical (enteropathic) hemolytic-uremic syndrome (HUS) . One week after the onset of diarrhea (acute phase of the disease), the E . coli O157 antibody titer was greater than or equal to 1:4,096 in 22 of 27 patients with HUS, compared with 4 of 249 controls, the majority of whom had O157 antibody titers of between 1:4 and 1:256 . This antibody response was observed in HUS patients with stool cultures positive and negative for E . coli O157 . Selective absorption with homologous LPS and heterologous LPS showed that the antibody response was specific for E . coli O157 . Because of its simplicity and ease of interpretation, the indirect hemagglutination assay described in this paper is recommended for the serological diagnosis of E . coli O157 infections in patients with HUS.

Tijdschr Diergeneeskd, 1992 Apr 15, 117(8), 235 - 8
{Enterohemorrhagic Escherichia coli O157:H7, an underestimated food pathogen? A literature review}; Bredie WL et al.; Escherichia coli O157:H7 has recently been recognised as a human pathogen involved in outbreaks and sporadic cases of food-borne diseases in North America and Great Britain . At present, less is known about the significance of E . coli O157:H7 as a cause of food-borne diseases in the Netherlands . This article will review current literature about this serotype, which is a predominant representative of the enterohaemorrhagic E . coli (EHEC) group . Biochemical features, toxins, pathogenesis, clinical characteristics, epidemiology and methods of isolation will also be discussed.

J Pediatr Gastroenterol Nutr, 1992 Apr, 14(3), 261 - 3
Bacterial ileocecitis caused by Escherichia coli O157:H7; Tarr PI et al.; Escherichia coli O157:H7 is most commonly linked to hemorrhagic colitis and the hemolytic uremic syndrome . Diagnostic ultrasound was used to demonstrate terminal ileum abnormalities suggestive of bacterial ileocecitis, a recently described entity that resembles acute appendicitis, in a patient whose stool culture yielded E . coli O157:H7 . This case extends the spectrum of disease caused by E . coli O157:H7 and expands the number of organisms that can cause bacterial ileocecitis.

Infect Immun, 1992 Apr, 60(4), 1613 - 7
Adherence of enterohemorrhagic Escherichia coli strains to a human colonic epithelial cell line (T84); Winsor DK Jr et al.; Enterohemorrhagic Escherichia coli (EHEC) produce Shiga-like toxins and attach to certain tissue culture cells . T84 cells are human colonic carcinoma cells . Unlike previously studied cell lines, T84 cells grown on collagen-coated surfaces polarize and produce tight junctions and desmosomes, forming a colonic epithelial cell layer in vitro . The purpose of this study was to examine the attachment of EHEC strains to the T84 cell line as a possibly more relevant in vitro model of EHEC adherence . Twelve EHEC strains were grown overnight in Penassay broth, suspended in minimal essential medium with and without 0.5% mannose, and incubated for 1 to 3 h with 5- to 7-day-old T84 cell monolayers grown on collagen-coated coverslips . The bacteria were removed, and attachment was quantitated microscopically . For both E . coli O157:H7 and other EHEC serotypes, there were marked differences in adherence between strains (range of 152 to 3 bacteria per oil immersion field) . Mannose partially inhibited the adherence of some EHEC strains . Adherence to the T84 cells appeared to be related to the amount of pili present and not to the serotype . Electron micrographs showed that a highly adherent strain (strain 43-12) tended to form microcolonies in the area of tight junctions on the T84 cell monolayers . In addition, the attachment of these EHEC strains to T84 cells correlated with their ability to adhere to isolated rabbit colonocytes (r = 0.91, P = 0.00004; without mannose) (r = 0.60, P = 0.04; with mannose) . These data show that there are EHEC strain-related differences in adherence which can be demonstrated in a human-derived colonic epithelial cell line (T84) and that these cells can be used to study EHEC adherence.

Infect Immun, 1992 Apr, 60(4), 1285 - 94
Susceptibility of porcine intestine to pilus-mediated adhesion by some isolates of piliated enterotoxigenic Escherichia coli increases with age; Nagy B et al.; Two porcine isolates of enterotoxigenic Escherichia coli (ETEC) (serogroup O157 and O141) derived from fatal cases of postweaning diarrhea and lacking K88, K99, F41, and 987P pili (4P- ETEC) were tested for adhesiveness to small-intestinal epithelia of pigs of different ages . Neither strain adhered to isolated intestinal brush borders of newborn (1-day-old) pigs in the presence of mannose . However, mannose-resistant adhesion occurred when brush borders from 10-day- and 3- and 6-week-old pigs were used . Electron microscopy revealed that both strains produced fine (3.5-nm) and type 1 pili at 37 degrees C but only type 1 pili at 18 degrees C . Mannose-resistant in vitro adhesion to brush borders of older pigs correlated with the presence of fine pili . These strains produced predominantly fine pili in ligated intestinal loops of both older and newborn pigs, but adherence was greater in loops in older pigs . Immunoelectron microscopic studies, using antiserum raised against piliated bacteria and absorbed with nonpiliated bacteria, of samples from brush border adherence studies revealed labelled appendages between adherent bacteria and intestinal microvilli . Orogastric inoculation of pigs weaned at 10 and 21 days of age indicated significantly (P less than 0.001) higher levels of adhesion by the ETEC to the ileal epithelia of older pigs than to that of younger ones . We suggest that small-intestinal adhesion and colonization by these ETEC isolates is dependent on receptors that develop progressively with age during the first 3 weeks after birth . Furthermore, our data are consistent with the hypothesis that the fine pili described mediate intestinal adhesion by the 4P- ETEC strains studied.

Indian J Med Res, 1992 Mar, 95, 71 - 6
Verocytopathic activity of Escherichia coli O157 & other 'O' serogroups isolated from patients of diarrhoea; Gupta S et al.; Twenty diarrhoeal isolates identified as Esch . coli O157 were screened for cytopathic activity on the continuous Vero cell line . Of these, seven strains (35%) showed cytopathic effect which was maximum on the 4th day after inoculation, with a maximum titre of 1 in 128 . The total loss of cytopathic activity was observed in the positive filtrates subjected to a temperature of 100 degrees C for 15 min, while heating at 65 degrees C for 15 min, resulted in partial loss of this activity . All the verocytopathic strains were obtained from infants and children and were devoid of heat labile (LT) and heat stable (ST) toxins as well as enteroinvasive property.

J Clin Microbiol, 1992 Feb, 30(2), 520 - 1
A cluster of cases of Escherichia coli O157 infection in a day-care center in a communal settlement (Kibbutz) in Israel; Lerman Y et al.; This is the first report in Israel of a cluster of cases of diarrhea associated with the isolation of Escherichia coli O157 in stool samples . E . coli O157:NM (nonmotile), producing verotoxins 1 and 2 was isolated from the stool samples of three infants less than 1 year of age with diarrhea and from a fourth asymptomatic infant staying in the same day-care class in a communal settlement (kibbutz) . The clinical presentation included nonbloody diarrhea without other symptoms . Surveillance efforts should be enacted in order to define the relative importance of E . coli O157 infections in Israel.

Zentralbl Bakteriol, 1992 Jan, 276(2), 176 - 88
Cloning and sequencing of a Shiga-like toxin II-related gene from Escherichia coli O157:H7 strain 7279; Meyer T et al.; Escherichia coli O157:H7 strains are newly recognized pathogens associated with haemorrhagic colitis and haemolytic-uremic syndrome . In addition to Shiga-like toxin types I and II known to be produced by E . coli O157 isolates, we have identified in E . coli O157:H7 strain 7279 a third toxin, designated SLT-IIvhc, that is neutralized neither by anti-SLT-I nor by anti-SLT-II antibodies . The genes for this toxin were isolated by using a PCR-mediated cell-free cloning technique . DNA sequence analysis revealed a high degree of homologies to SLT-II and several SLT-II variants . The predicted amino acid sequence of the A subunit of SLT-IIvhc differed from that of the O91:H7 toxin VT2ha and SLT-IIc from E . coli O157:H- strain E2511 by 2 and 3 amino acids, respectively . The amino acid sequence of its B subunit was identical to VT2ha and SLT-IIc but different from SLT-II and SLT-IIv . Immunological differences of SLT-IIvhc and SLT-II as well as their different toxicity to HeLa cells presumably resulted from the small deviations within the primary structure of the B subunit.

Clin Neuropathol, 1992 Jan-Feb, 11(1), 45 - 8
Bilateral striatal necrosis in hemolytic-uremic syndrome; Hrynchak M et al.; A 41-year old resident of a nursing home presented with bloody diarrhea, and subsequently developed hemolytic-uremic syndrome . E . coli serotype O157:H7 was isolated from the stool culture . At autopsy she was found to have bilateral symmetrical striatal necrosis involving mainly the putamen and lateral globus pallidus . The main microscopic findings consisted of coagulative necrosis, endothelial damage and microthrombosis . Scattered microscopic lesions of similar appearances were noted in the parietal cortex, external capsule and fornix . This case is of particular interest because of the rarity of bilateral striatal necrosis in hemolytic-uremic syndrome and the recent experimental data which implicate E . coli endotoxin in the pathogenesis of cerebral lesions in this syndrome.

Microbiol Immunol, 1992, 36(10), 1077 - 85
Effects of human intravenous immune globulin on diarrhea caused by Shiga-like toxin I and Shiga-like toxin II in infant rabbits; Havens PL et al.; Shiga toxin and the related Shiga-like toxins (SLT), produced by Escherichia coli, can cause hemorrhagic colitis and hemolytic uremic syndrome (HUS) . Human intravenous immune globulin (HIVIg) blocks the cytotoxicity of some SLTs in vitro . To examine the ability of HIVIg to modify disease caused by Shiga-like toxin I or Shiga-like toxin II (SLT-I or SLT-II), we injected 3-day-old rabbits intraperitoneally with SLT-containing cell-free supernatants from Escherichia coli O157: H7 . A subset of rabbits was treated with subcutaneous HIVIg . All rabbits given 10(4) CD50 of SLT-I developed severe diarrhea, and 5 died . When HIVIg 500 mg/kg was given in addition to SLT-I, only 6 of 18 rabbits (33.3%) developed diarrhea (P < 0.0001), and 1 died . HIVIg 500 mg/kg or 1,000 mg/kg protected against diarrhea when given one hour prior to toxin . HIVIg 1,000 mg/kg was protective when administered one hour after toxin, but not at 6 or 24 hr . Seventeen of 18 rabbits given 10(6) CD50 of SLT-II developed severe diarrhea, and 4 died . In contrast to SLT-I-associated disease, HIVIg had no effect on diarrhea in rabbits given SLT-II . We conclude that HIVIg protects infant rabbits from diarrhea and death caused by intraperitoneally administered SLT-I, but does not affect the course of SLT-II-associated illness.

Zentralbl Bakteriol, 1992 Jan, 276(2), 243 - 53
Characterization of Shiga-like toxin producing Escherichia coli (SLTEC) isolated from calves with and without diarrhoea; Wieler LH et al.; To determine if shiga-like toxin producing Escherichia coli (SLTEC) are involved in neonatal calf diarrhoea, isolated E . coli strains from diarrhoeic and non-diarrhoeic calves were characterized for shiga-like toxin (SLT) by colony blot hybridization and cytotoxicity assays . None of 150 E . coli strains isolated from diarrhoeic calves in 1985-1988 was positive for SLT, while 7/232 (3.0%) isolated in 1989 were positive for SLT . In contrast, samples collected during 1989 and 1990 from diarrhoeic calves were 21.9% SLTEC positive, and samples from non-diarrhoeic calves were 12.9% SLTEC positive . SLT I positive E . coli strains were isolated more often from diseased (17.8%) than from healthy animals (5.0%), while SLT II positive E . coli were more often detected in non-diarrhoeic (8.9%) than in diarrhoeic calves (4.1%) . The mean percentage of SLT I positive E . coli in the whole E . coli flora of the samples was significantly higher in diarrhoeic than in healthy animals, implying a pathogenic role of SLT I producing E . coli in neonatal calf diarrhoea . Enterohemolysin was produced by 70.8% of the SLT I producing E . coli strains examined . Determination of O- and K-antigens of SLT positive E . coli revealed a highly diverse spectrum of SLTEC O-groups in calves . While no E . coli isolate belonged to serotype O157:H7, classical human enteropathogenic E . coli O-groups (O26, O111, O128) were detected . These results support the theory that cattle serve as a reservoir for human SLTEC infection.

Acta Clin Belg, 1992, 47(6), 387 - 96
Infections with verotoxin-producing Escherichia coli; Pierard D; The production of verotoxins is one of the mechanisms by which Escherichia coli can produce diarrhea . First associated with hemorrhagic colitis and hemolytic uremic syndromes, the so-called verotoxin-producing Escherichia coli strains (VTEC) have been shown to cause also uncomplicated watery or bloody diarrhea . They have been found both in outbreaks and sporadic cases and were isolated in all countries where they were searched for . Inadequately cooked meat of bovine origin is thought to be the first source of contamination but person-to-person transmission has also been demonstrated . Until now most studies focused on serotype O157:H7, easy to detect thanks to its rare biotype . However a screening by PCR confirmed by VTEC strain isolation and cytotoxicity testing showed that in Belgium only 18% of VTEC strains belong to this serotype.

Appl Environ Microbiol, 1991 Oct, 57(10), 2951 - 5
Detection and production of verotoxin 1 of Escherichia coli O157:H7 in food; Weeratna RD et al.; Verotoxin 1 (VT1) is a recognized virulence factor of Escherichia coli O157:H7, a cause of severe food-borne disease . The public health significance of preformed verotoxin in food is unknown, and relatively little research has been done to determine the production of VT1 in food . The purposes of this study were to develop a sensitive method to detect VT1 in milk and in ground beef and to determine the conditions for VT1 production in these foods . A sandwich enzyme-linked immunosorbent assay in which we used VT1-specific monoclonal antibody 9C9F5 as the capture antibody and a rabbit polyclonal antibody raised against VT2 as the detection antibody was developed for the detection and quantification of VT1 in milk and in ground beef . The enzyme-linked immunosorbent assay was sensitive to a minimum of 0.5 ng of VT1 per ml of milk and 1.0 ng of VT1 per g of ground beef . The greatest amount of VT1 detected in milk (306 ng/ml) was detected in samples that were incubated at 37 degrees C with agitation (160 rpm) for 48 h . Very little toxin (1 ng/ml) was produced at 25 or 30 degrees C within 96 h . VT1 production was greater in ground beef than in milk; 452 ng of VT1 per g was produced in beef at 37 degrees C in 48 h . Relatively little VT1 was produced in beef within 96 h at 25 and 30 degrees C (2.1 and 9.8 ng of VT1 per g, respectively) . Our results indicate that ground beef is a better medium for VT1 production than milk.(ABSTRACT TRUNCATED AT 250 WORDS)

Microbiologia, 1991 Sep, 7(2), 57 - 73
Enterotoxins, colonization factors and serotypes of enterotoxigenic Escherichia coli from humans and animals; Blanco J et al.; Enterotoxigenic Escherichia coli (ETEC) strains may synthesize both thermolabile (LT-I and LT-II) and thermostable (STa and STb) enterotoxins . Whereas thermolabile enterotoxins are high molecular weight proteins (85,000 d-90,000 d) composed by a single enzymatic A subunit combined with five B subunits which enable toxin for the receptor recognition, thermostable enterotoxins are small peptide chains with molecular weight between 1,900 d and 5,000 d . In addition to the synthesis of enterotoxins, the ability of ETEC strains to cause diarrhoea is also conditioned by the possession of colonization factors which enable bacteria adhere-to and colonize the luminal surface of small bowel . Colonization factors in ETEC strains were located in rigid fimbriae and flexible fibrils constituted by protein subunits ranging in size from 14,500 d to 31,000 d and usually responsible for mannose-resistant haemagglutination with determined erythrocyte species . Both enterotoxins and colonization factors are controlled by plasmids . There exist plasmids which may code separately enterotoxins and colonization factors, and besides there also exist recombinant plasmids coding together these two virulence factors . Human ETEC strains may synthesize LT-I and/or STa enterotoxins, they may possess the colonization factors named CFA/I, CFA/II, CFA/III or CFA/IV, and they belong mainly to serogroups O6, O8, O15, O20, O25, O27, O63, O77, O78, O114, O115, O126, O128, O139, O148, O153, O159 and O167 . ETEC strains from porcine origin synthesize LT-I, STa and/or STb, they possess the colonization factors K88, P987, K99 or F41, and they usually belong to serogroups O8, O9, O20, O45, O64, O101, O115, O138, O141, O147, O149 and O157 . Bovine and ovine ETEC strains are usually STa producers harbouring on the bacterial surface K99 or F41 colonization factors and they belong to serogroups O8, O9 and O101 . Nevertheless, some particular bovine ETEC strains synthesizing LT-II have been described . Thus, a high specificity level between ETEC strains causing diarrhoea in humans and domestic animals can be observed . This is mainly due to the specific recognition between bacterial colonization factors and the epithelial receptors during host-parasite interaction.

N Engl J Med, 1991 Aug 8, 325(6), 398 - 403
Improved survival in thrombotic thrombocytopenic purpura-hemolytic uremic syndrome . Clinical experience in 108 patients; Bell WR et al.; BACKGROUND AND METHODS . Thrombotic thrombocytopenic purpura-hemolytic uremic syndrome (TTP-HUS) is characterized by microangiopathic hemolytic anemia, thrombocytopenia, fever, central nervous system abnormalities, and renal dysfunction . In early reports the mortality approached 100 percent . A treatment protocol was introduced in 1979 for patients admitted to Johns Hopkins Hospital with the diagnosis of TTP-HUS . Treatment regimens included 200 mg of prednisone a day, for patients with minimal symptoms and no central nervous system symptoms, and prednisone plus plasma exchange, for patients with rapid clinical deterioration who did not improve after 48 hours of prednisone alone and for patients presenting with central nervous system symptoms and rapidly declining hematocrit values and platelet counts . RESULTS . A total of 108 patients were treated, and 91 percent survived . Prednisone alone was judged to be effective in 30 patients with mild TTP-HUS (two relapses and two deaths) . Plasma exchange plus prednisone was given to 78 patients with complicated TTP-HUS, resulting in 67 relapses and 8 deaths . Relapses occurred in 22 of 36 patients given maintenance plasma infusions . Neither splenectomy nor treatment with aspirin and dipyridamole was effective in those with a poor response to plasma exchange . None of the 71 patients tested had positive cultures for O157:H7 Escherichia coli . Nine percent of the patients were pregnant, and none gave birth to infants with TTP-HUS . CONCLUSIONS . Effective treatment with 91 percent survival is available for patients with TTP-HUS.

J Pediatr, 1991 Aug, 119(2), 218 - 24
Epidemiology of hemolytic-uremic syndrome in Canadian children from 1986 to 1988 . The Canadian Pediatric Kidney Disease Reference Centre; Rowe PC et al.; OBJECTIVE: To define the epidemiologic features of childhood hemolytic-uremic syndrome (HUS) on a national level in Canada, to determine the proportion of patients in whom Escherichia coli O157:H7 was isolated from stools, and to examine risk factors for more severe HUS . DESIGN: From January 1986 to December 1988, patients with HUS were reported prospectively to the Canadian Pediatric Kidney Disease Reference Centre, a national registry for pediatric renal disorders, or were identified retrospectively through a medical records search at participating institutions . SETTING: All children's hospitals in Canada and the children's wards of general hospitals in Canadian cities with populations greater than 350,000 . PATIENTS: Two hundred twenty-six children, including 126 girls . MEASUREMENTS AND MAIN RESULTS: The average annual incidence of HUS in children younger than 15 years was 1.44 per 100,000; the peak age-specific incidence was 3.11 per 100,000 younger than 5 years . The incidence of HUS varied by region; the risk of HUS in Alberta was 2.9 times that in Ontario (p less than 0.0001) . Of the 169 patients whose stools were screened, E . coli O157:H7 was isolated in 87 (51%) . Risk factors for prolonged dialysis or death included young age, seizures, elevated white blood cell count at admission to hospital, and shorter, more severe prodromal illness . The rate of dialysis was higher in female patients (55% vs 39%; p = 0.02) . CONCLUSIONS: HUS is relatively common in Canadian children younger than 5 years, and is strongly associated with E . coli O157:H7 infection . Reasons for the striking regional variation in the incidence of HUS and for the increased rate of dialysis in female patients are unexplained and deserve further investigation.

J Infect Dis, 1991 Aug, 164(2), 338 - 43
An outbreak of Escherichia coli O157:H7 colitis associated with consumption of precooked meat patties; Belongia EA et al.; An outbreak of Escherichia coli O157:H7 hemorrhagic colitis at a Minnesota junior high school in October 1988 comprised 32 cases among 1562 students (attack rate, 2.0%) . Four children were hospitalized; none developed hemolytic-uremic syndrome . Case children were more likely than controls to have eaten heat-processed meat patties (odds ratio, 6.2; 95% confidence interval, 2.0-20.1; P less than .001) in the school cafeteria on a specific day . The minimum estimated attack rate among students who ate these patties was 8% . The patties should have been sufficiently cooked by the manufacturer to destroy enteric pathogens before they were frozen and distributed . E . coli were cultured from frozen patties that were manufactured at the same plant on the same dates as the implicated patties, but serotype O157:H7 was not isolated . Heat-processed meat patties may serve as vehicles for E . coli O157:H7 infection, and currently there are no federal or state regulatory standards to ensure the safety of these products.

Appl Environ Microbiol, 1991 Jul, 57(7), 2091 - 3
Examination of retail chickens and sausages in Britain for vero cytotoxin-producing Escherichia coli; Smith HR et al.; Samples from chickens and pork sausages were examined for the presence of Vero cytotoxin-producing Escherichia coli by using DNA probes for the Vero cytotoxin genes . Hybridization was detected in 25% of the 184 sausage samples, but none of the chickens was positive . No E . coli O157:H7 strains were isolated, and serotyping showed that the Vero cytotoxin-producing E . coli strains belonged to eight different O serogroups and that six strains had an unidentifiable O antigen.

Am J Vet Res, 1991 Jul, 52(7), 1051 - 5
Evaluation of a live avirulent Escherichia coli vaccine for K88+, LT+ enterotoxigenic colibacillosis in weaned pigs; Francis DH et al.; Live, avirulent Escherichia coli vaccine strains were constructed and tested for efficacy in preventing colibacillosis in 4-week-old pigs . Either or both of 2 plasmids were inserted into avirulent E coli strain G58-1 (0101:NM) . These plasmids were pPMC4, which encodes for LTb subunits of heat-labile enterotoxin, and pDHF1, which encodes for K88ac fimbriae . Litter- and weight-matched pigs were removed from sows when they were 10 days old and vaccinated orally with the constructed strains or with G58-1 (negative control vaccine) when they were 2 weeks old and 5 days later . All pigs were challenge-inoculated with virulent E coli strain 3030-2 (O157:K88, LT+, STb+) 2 weeks after the first vaccination . Only 1 pig vaccinated with G58-1/pPMC4/pDHF1 developed diarrhea and none died following challenge inoculation . Seventeen of 31 control pigs developed diarrhea and 11 died . Of 18 pigs vaccinated with G58-1/pDHF1 then challenge-inoculated with the virulent strain, 5 developed diarrhea and 2 died . Fifteen of 18 litter- and weight-matched controls developed diarrhea and 8 died . When compared with G58-1 (negative control), G58-1/pPMC4 afforded no protection to pigs challenge-inoculated with 3030-2.

J Clin Microbiol, 1991 Jun, 29(6), 1225 - 31
Serotype O157:H7 Escherichia coli from bovine and meat sources; Dorn CR et al.; Serotype O157:H7 Escherichia coli strains from several different bovine and meat (beef) sources were studied to determine the diversity of their virulence properties and to compare their plasmid characteristics . Eighteen strains from cattle feces, 2 from water buffalo feces, 3 from beef samples, and 2 from feces of human hemolytic uremic syndrome cases were examined . All of these strains hybridized with the CVD419 DNA probe which identifies serotype O157:H7 and many other serotypes of verocytotoxin-producing E . coli . Of 15 bovine strains that hybridized with two verocytotoxin DNA probes, 8 hybridized with both verocytotoxin 1 (VT1) and VT2 probes, 5 hybridized with only the VT2 probe, and 2 hybridized with only the VT1 probe . This distribution was similar to that reported for O157:H7 E . coli isolated from humans . All three beef isolates hybridized with both VT1 and VT2 probes . All strains that hybridized with the VT probes were positive in the verocytotoxin assay, and all probe-negative strains were negative in the assay . All the strains possessed large plasmids with molecular sizes ranging from 53 to 64 MDa . Fifteen of the 20 cattle and water buffalo strains had one or more additional small plasmids . Restriction patterns resulting from HindIII, SmaI, and BamHI digestions of the large plasmids were used to compare all possible pairs of five different single plasmid-bearing strains from different countries (Egypt, England, and the United States) . The restriction patterns of these strains were distinct, and the mean coefficients of similarity for these comparisons ranged from 71 to 91%, indicating a moderate degree of genetic diversity . This diversity and the presence of multiple plasmids in many bovine and human O157:H7 strains reinforce the usefulness of plasmid analysis in future studies . Only four of the 20 bovine strains and 1 of the 3 beef strains possessed the capability for adherence to HEp-2 and Intestine 407 cells in the presence of mannose, indicating that in vitro expression of localized adherence is not a universal property of O157:H7 strains of bovine origin.

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