E coli O157

J Clin Microbiol, 1991 May, 29(5), 1016 - 9
Enzyme-linked immunosorbent assay for products of the 60-megadalton plasmid of Escherichia coli serotype O157:H7; Toth I et al.; Eighty strains of pathogenic Escherichia coli, representing each of the major diarrheal disease-causing groups, were examined by direct enzyme-linked immunosorbent assay (ELISA) for the presence of proteins associated with a 60-MDa plasmid from E . coli serotype O157:H7 . Antiserum specific for plasmid-encoded proteins was prepared by immunizing a rabbit with a wild-type E . coli O157:H7 strain (strain 7785) and absorbing the serum with a plasmid-cured derivative (strain 2-45) . Use of this antiserum in Western immunoblot analysis detected two proteins of 82 and 92 kDa in strain 7785 but not in strain 2-45 . All 16 wild-type E . coli O157:H7 strains and all 10 Shiga-like toxin (SLT)-producing E . coli strains of serotypes other than O157 were ELISA positive . Thirteen of 14 enterotoxigenic and all of 24 enteroinvasive E . coli strains were ELISA negative, as were all of 16 E . coli strains isolated from healthy persons . Of 16 traditional enteropathogenic E . coli (EPEC) serotypes, 10 were ELISA positive, including 10 of 12 strains carrying the EPEC adherence factor gene . Absorption of the serum with an EPEC adherence factor-positive EPEC eliminated EPEC reactivity . This study demonstrates that two plasmid-mediated proteins are common to E . coli O157:H7 strains and to SLT-producing strains of other serotypes . Detection of these proteins by ELISA provides a sensitive and specific screening test for identifying SLT-producing E . coli of both O157 and non-O157 serotypes . Identification of the cross-reactive proteins found in EPEC could provide the basis for a single assay to detect both EPEC and SLT-producing E . coli.

Int J Food Microbiol, 1991 May, 13(1), 31 - 9
DNA hybridization and latex agglutination for detection of heat-labile- and shiga-like toxin-producing Escherichia coli in meat; Notermans S et al.; DNA-hybridization and latex-agglutination tests were used for screening of a group of Escherichia coli isolates for heat-labile enterotoxin (LT)- and shiga-like toxin (SLT1 or VT1) -producing strains, respectively . Strains tested originated from 162 meat samples (poultry, pigs and beef) chosen at random . Additionally LT- and SLT1-producing reference strains were tested . The DNA-hybridization technique allowed screening of large numbers of strains, whereas large scale testing of strains by latex agglutination was laborious . Of 800 E . coli strains tested by DNA hybridization none contained the gene encoding LT . Production of LT as tested by latex agglutination was not found . The gene encoding SLT1 was detected in 10 of the 800 isolates tested . None of these strains, however, showed cytotoxicity on Vero cells . Serotyping was done with sorbitol-negative E . coli strains, first by using the latex-agglutination test for O157 followed by complete serotyping . No E . coli of serogroup O157 were found . Therefore the results obtained also indicate that routine screening of E . coli isolated randomly from food for toxin production is not useful and should be limited to food-borne disease outbreaks with an etiology resembling an E . coli infection.

MMWR Morb Mortal Wkly Rep, 1991 Apr 26, 40(16), 265 - 7
Foodborne outbreak of gastroenteritis caused by Escherichia coli O157:H7--North Dakota, 1990; Surveillance of Escherichia coli O157 isolation and confirmation et al.; Enteric Diseases Branch, Division of Bacterial and Mycotic Diseases, Center for Infectious DiseasesIn 1989, to examine patterns of testing for Escherichia coli O157:H7 in state public health laboratories (SPHLs), CDC conducted a survey to determine the availability and type of Escherichia coli O157:H7 testing in SPHLs during 1988 and the number of isolates confirmed at SPHLs if such testing was available . The results were compared with information on isolates submitted for confirmatory testing at CDC in 1988 . Thirty-nine (78%) of the 51 SPHLs were testing for E . coli O157:H7 in 1988; 26 confirmed at least one E . coli O157 isolate in that year . CDC confirmed isolates from three additional states . A total of 489 E . coli O157:H7 or E . coli O157:NM isolates were identified, with the largest numbers being reported from Washington (156), Oregon (64), Minnesota (63), and Massachusetts (36) . These results show that E . coli O157 has been detected in most areas of the United States . Infections are apparently concentrated in northern states; however, improved surveillance data are needed to determine regional incidence and trends.

J Clin Microbiol, 1991 Apr, 29(4), 745 - 52
Detection of genes for fimbrial antigens and enterotoxins associated with Escherichia coli serogroups isolated from pigs with diarrhea; Harel J et al.; A total of 1,226 Escherichia coli strains isolated from 1979 to 1989 from pigs with diarrhea were examined for serogroup and fimbrial antigen F4 (K88) production . Four main patterns of isolation of the various serogroups were observed, depending on the ages of the pigs from which isolates were obtained and the production of F4 . In pattern I, serogroups O8:K"S16", O9:K35, O9/O101:K30, O9/O101:K103, O9 (group), O20:K101, and O64:K"V142" were predominant in pigs aged 0 to 6 days (41.9% of isolates) and were less frequent in pigs aged 7 to 27 days (24.6% of isolates) but were rarely found in pigs aged 28 to 60 days (4.0% of isolates) . In pattern II, the F4-associated serogroups O8:K"4627", O157:K"V17", O149:K91, and O147:K89 were predominant in pigs aged 7 to 27 days (29.8% of isolates) and in pigs aged 28 to 60 days (35.0% of isolates) . In pattern III, serogroups O8 (group), O115:K"V165", and O147:K89 were rarely isolated from pigs aged 0 to 6 days but were equally distributed in pigs aged 7 to 27 days (10.1% of isolates) and in pigs aged 28 to 60 days (10.9% of isolates) . In pattern IV, serogroups O138:K81, O139:K82, O141:K85ac, O45:K"E65", and O26:K60 were most frequently isolated in pigs aged 28 to 60 days (19.3% isolates) . Over the period from 1979 to 1989, the proportion of isolates belonging to serogroups of pattern II and the proportion of F4 isolates within the serogroup O157:K"V17" declined, whereas the proportion of isolates of serogroups O147:K89, O8:K"S16", and O9:K35 increased . For 228 isolates selected from the most important serogroups, good agreement was observed between the results of gene probes and immunofluorescence for the detection of fimbrial antigens F4 (K88), F5 (K99), F6 (987P), and F41 and between the results of gene probes and biological assays for the detection of heat-labile enterotoxin (LT) and heat-stable enterotoxins a and b (STa and STb) . The STa gene was mostly associated with isolates of pattern I serogroups, which had the F5, F6, and F41 genes alone or in various combinations . The LT and/or STb genes, with the F4 gene, mostly were observed in isolates of pattern II serogroups . The STb gene alone was observed mostly in isolates of pattern III serogroups, although isolates were negative for all fimbrial antigen genes . Similarly, isolates of pattern IV serogroups were negative for all fimbrial antigen genes and rarely positive for the enterotoxin genes . However, verotoxin production was associated with isolates of serogroups O138:K81 and O139:K82 . The most important pathotypes among enterotoxigenic isolates in this study were F4:LT:STb, F5:STa, STb, F5:F41:STa, F4:STb, F6, STa, and LT.

Infect Immun, 1991 Mar, 59(3), 1065 - 73
Two copies of Shiga-like toxin II-related genes common in enterohemorrhagic Escherichia coli strains are responsible for the antigenic heterogeneity of the O157:H- strain E32511; Schmitt CK et al.; Thirty-two clinical isolates of Shiga-like toxin (SLT)-producing Escherichia coli associated with single cases or outbreaks of bloody diarrhea, hemorrhagic colitis, the hemolytic uremic syndrome, or edema disease of swine were examined for multiple copies of genes belonging to the slt-I or slt-II toxin families . Five of 19 strains that were known to produce SLT-II or to hybridize to slt-II-specific probes by colony blot were found by Southern hybridization to contain two copies of toxin genes related to slt-II . The genes for two toxins closely related to slt-II were cloned from one of the isolates, Escherichia coli O157:H- strain E32511 . One copy of the operon was found to be essentially identical to slt-II; it differed from slt-II by only one nucleotide base . This single nucleotide difference did not affect the predicted amino acid sequence . The predicted amino acid sequence of the A subunit of the second operon was identical to that of SLT-II, but the predicted amino acid sequence of the B subunit was identical to that of the B2F1 toxin VT2ha . We designated this second operon slt-IIc . Neutralization assays using several monoclonal antibodies and polyclonal antiserum prepared against SLT-II showed that SLT-IIc was antigenically related to but distinct from SLT-II.

Infect Immun, 1991 Mar, 59(3), 890 - 9
Outer membranes are competitive inhibitors of Escherichia coli O157:H7 adherence to epithelial cells; Sherman P et al.; Escherichia coli of serotype O157:H7 are Vero cytotoxin-producing enteric pathogens that have been associated recently with sporadic cases and outbreaks of hemorrhagic colitis and with the hemolytic-uremic syndrome . Adherence of many enteropathogenic bacteria to mucosal surfaces is a critical step in the pathogenesis of diarrheal disease . We showed previously that adherence of E . coli O157:H7 strain CL-56 to epithelial cells in vitro is inhibited by outer membranes . In this study we examined whether outer membranes from a series of E . coli O157:H7 strains mediated competitive inhibition of bacterial binding to epithelial cells grown in tissue culture . We also determined which constituents of the outer membrane mediated inhibition of CL-56 adherence . Binding of six O157:H7 strains to HEp-2 cells was determined by quantitating the number of adherent bacteria in the presence and absence of outer membranes which were extracted from each strain with N-lauroyl sarcosinate (1.7%, wt/vol) . After separation of outer membranes by gel electrophoresis, four bands (94, 40, 36, and 30 kDa) were collected by electroelution . Immune sera were raised in rabbits to each of the four eluted bands . Outer membrane extracts from each of the six O157:H7 strains inhibited binding of homologous organisms to the HEp-2 cells . At dilutions which did not cause bacterial agglutination, antiserum raised against the 94-kDa outer membrane protein showed maximal inhibition of bacterial adherence (17.0 +/- 7.3% adherence of control levels) . Growth of bacteria in iron-depleted broth did not affect their binding to HEp-2 cells, suggesting that iron-regulated outer membranes were not involved . Fluid accumulation in ileal ligated loops of rabbits in response to E . coli O157:H7 challenge was diminished following both parenteral immunization with outer membranes extracted from the homologous strain and coincubation of organisms with immune serum which contained antibodies to outer membrane extracts . These data indicate that outer membranes are competitive inhibitors of E . coli O157:H7 adherence . Specific constituents of the outer membrane may function as bacterial attachment factors (i.e., adhesins) for E . coli O157:H7 adherence to epithelial cell surfaces.

Appl Environ Microbiol, 1991 Jan, 57(1), 320 - 3
Identification of uidA gene sequences in beta-D-glucuronidase-negative Escherichia coli; Feng P et al.; A probe specific for the uidA gene of Escherichia coli hybridized with 112 of 116 E . coli isolates examined, including 31 beta-D-glucuronidase-negative and 12 enterohemorrhagic E . coli serotype O157:H7 isolates . Southern hybridizations confirmed the presence of a 900-bp HinfI fragment from the uidA gene in all isolates examined, suggesting that uidA gene sequences are present in most E . coli.

Pediatr Res, 1991 Jan, 29(1), 14 - 9
The effect of postnatal age on the adherence of enterohemorrhagic Escherichia coli to rabbit intestinal cells; Ashkenazi S et al.; Enterohemorrhagic Escherichia coli (EHEC) are associated with hemorrhagic colitis and hemolytic uremic syndrome . These illnesses are typically seen in young children, but are rare before 6 mo of age . The cause of this age restriction is unclear . Because bacterial adherence to intestinal mucosa is considered a critical initial event in pathogenesis, we studied the ontogeny of the adherence of EHEC (O157:H7 and other serotypes) isolated from children with diarrhea, hemorrhagic colitis, or hemolytic uremic syndrome . Adherence was quantitatively determined by incubating radiolabeled bacteria with viable rabbit intestinal cells, which were prepared by treating loops of distal ileum and proximal colon with EDTA, DTT, and citrate . Cells obtained from animals of different ages were studied simultaneously . The adherence of the various EHEC strains varied significantly . A non-O157:H7 E . coli strain 43-12 bound best (35 and 32 bacteria/cell to ileal and colonic cells, respectively) with 48-60% inhibition by D-mannose and alpha-methyl mannoside (p less than 0.01) and 20-28% inhibition by L-fucose (p less than 0.05), but no significant inhibition by other carbohydrates . Analysis of variance and polynomial regression showed that postnatal age significantly affected the adherence to ileal and colonic cells . Adherence during the 1st wk of life was 13-19% of that in the adult animal; it increased gradually, reaching the adult level at about 4 wk of age . Our study shows that postnatal age affects the adherence of EHEC to intestinal cells . These findings are compatible with postnatal development of gut receptors and may be relevant to the age-related risk of EHEC disease in children.

Zentralbl Bakteriol, 1991 Jan, 274(4), 496 - 506
Clinical and genetic aspects of Shiga-like toxin production in traditional enteropathogenic Escherichia coli; Bitzan M et al.; Cell culture tests, DNA colony blot hybridization and polymerase chain reaction were used to examine classical enteropathogenic Escherichia coli (EPEC) for the presence of Shiga-like toxin (SLT) . Fifteen of 155 strains from West Germany, originally identified as EPEC on the basis of serotyping, were shown to harbor either SLT-I or SLT-II genes . All strains that hybridized with the 20-base oligonucleotide probes which are complementary to slt-IA or slt-IIA sequences derived from the genomic DNA of enterohemorrhagic E . coli O157:H7 strain 933 produced moderate or high levels of cytotoxin in Vero and HeLa cell assays . Four additional strains of low to moderate cytotoxicity did not hybridize with either probe . Five different serogroups producing SLTs were identified: O26, O55, O111, O119 and O128 . All three SLT-positive E . coli O26:H11 and four of five E . coli O111:H- isolates hybridized with a 3.4 kilobase fragment (CVD 419 probe) derived from the 60-megadalton plasmid of EHEC O157:H7 . Seven of the 15 SLT-gene positive strains were associated with bloody diarrhea, six isolates were from patients with hemolytic uremic syndrome (HUS) . Based on their clinical, epidemiological, pathogenic and genetic features SLT-producing E . coli among classical EPEC mimic enterohemorrhagic E . coli O157:H7 and might be considered as EHEC.

Microbiol Immunol, 1991, 35(7), 515 - 24
Experimental infection of specific-pathogen-free mice with enterohemorrhagic Escherichia coli O157:H7; Lai XH et al.; By subcutaneous inoculation of 10(8) CFU of enterohemorrhagic E . coli O157:H7, specific-pathogen-free mice revealed most of the symptoms and histological changes observed in patients . The histological changes in intestine were mainly seen in the distal parts of small intestine and the cecum . Vacuolation of villi in the cecum was also observed . The histological changes in the kidneys of the infected mice were featured as the swollen epithelial cells of glomeruli and the marked thickening of glomerular capillaries with barely visible lumens . Unexpected findings in the bronchiole were characterized by sloughing of the epithelial cells of bronchiolar wall, leading to partial or complete obstruction of the lumens . Histological changes in the spleen, liver and lymphnodes were also observed . The bacteria were recovered from the feces, contents of small intestine, and samples taken from kidney, liver, heart, spleen, different parts of small intestine, cecum, and colon . By using peroxidase-antiperoxidase (PAP) assay with polyclonal antibodies against "O" antigen of E . coli O157:H7, it was observed that the samples taken from the brain, kidney, ileum, cecum, spleen, and liver gave positive reactions . Feces and contents of small intestine obtained from all of the infected animals were positive by occult blood test . These results show that the experimental infection of E . coli O157:H7 in this model is systemic in nature.

Epidemiol Infect, 1990 Dec, 105(3), 511 - 20
Extended phage-typing scheme for Escherichia coli O157:H7; Khakhria R et al.; In Canada, the number of human isolates of verotoxigenic (VT + ve) Escherichia coli O157:H7 from diarrhoeal cases and haemolytic uraemic syndrome and haemorrhagic colitis has increased from 25 in 1982 to 2384 in 1989 . A total of 3273 VT + ve E . coli O157:H7 strains (3255 strains isolated in Canada and 18 isolates from other countries) were phage typed . The phage typing scheme has been extended from 14 to 62 phage types . Of these, five types occurred exclusively in other countries (type 47 in Japan; and types 49, 50, 51 and 52 in the U.K.) . Thirty-five different phage types were identified in Canada; only nine of these (1, 2, 4, 8, 14, 21, 23, 31 and 32), each accounted for more than 1% of the cases from human sources . The same nine types were the only ones observed among the isolates from non-human sources (meat and slaughter houses) suggesting a food-borne transmission in most of the human cases . Phage types 1 (30.5%); 4 (21%); 8 (13.5%); 31 (8.9%) and 14 (8%) were encountered in varying frequencies in most of the provinces; infrequently occurring phage types also showed regional variation . Thirteen different phage types were identified among 151 outbreaks representing 556 isolates of E . coli O157:H7 . More than one phage type were encountered in 12 outbreaks whereas in 141 outbreaks, all strains in each, had the same phage type.

Infection, 1990 Nov-Dec, 18(6), 352 - 6
Verotoxigenic (enterohaemorrhagic) Escherichia coli in infants and toddlers in Czechoslovakia; Bielaszewska M et al.; The results of the investigation indicate that verotoxigenic Escherichia coli (VTEC) belonging to enteropathogenic and other serogroups including Escherichia coli O157:H7 or H- are important enteropathogens in infants and toddlers in Czechoslovakia . As to enteropathogenic serotypes, verotoxin (VT) production was proved most frequently in strains of serogroup O26, and also O111 and O128 . Diseases caused by them were as a rule manifested by febrile watery diarrhoea with mucus in the stool . In two of five infants with Escherichia coli O26 :H11 with VT1 production in titres of greater than or equal to 1:512 (blood was present) in the stool and one suffered from marked abdominal pain . In one infant haemorrhagic colitis due to Escherichia coli O157:H- was found . Haemolytic uraemic syndrome associated with VTEC of serogroups O157, O26, O18, O5 and O1 with VT1 and/or VT2 was observed in six children including five who contracted the disease during an outbreak in a small town, and the source of infection was probably contaminated water . Five children recovered and one died; the postmortem examination revealed haemorrhagic colitis and necrosis of the renal cortex . Haemorrhagic colitis caused by Escherichia coli O157 in infants and toddlers differed from the course hitherto described in older subjects by fever and the presence of mucus in the stools.

N Engl J Med, 1990 Oct 25, 323(17), 1161 - 7
The epidemiology and clinical aspects of the hemolytic uremic syndrome in Minnesota; Martin DL et al.; BACKGROUND . The frequency of the hemolytic uremic syndrome, characterized by microangiopathic hemolytic anemia, thrombocytopenia, and renal failure, is increasing . Although Escherichia coli serotype O157:H7 has been implicated as a causative agent, more information is needed about the basic epidemiology and clinical aspects of this syndrome . METHODS . We conducted a retrospective population-based study of hemolytic uremic syndrome in Minnesota residents less than 18 years of age from 1979 through 1988 to assess trends in disease occurrence, describe the clinical illness, and identify predictors of disease severity and outcome . We also conducted a case-control study of patients with onsets of illness from 1986 through 1988 to examine risk factors . RESULTS . One hundred seventeen patients were identified . The mean annual incidence increased from 0.5 case per 100,000 child-years among children less than 18 in 1979 (6 cases) to 2.0 cases per 100,000 in 1988 (26 cases) (P = 0.000004) . E . coli O157:H7 was isolated from 13 of 28 patients (46 percent) who had stool specimens submitted for testing . For those who presented with typical hemolytic uremic syndrome, an elevated polymorphonuclear-leukocyte count on hospital admission, a shorter duration of prodrome, and the presence of bloody diarrhea were predictive of severe disease . In the case-control study, the patients were more likely to attend large daycare centers (more than 50 children) than were the controls (odds ratio, 10.2; P = 0.03), suggesting that day-care attendance may be a risk factor . On the basis of the population-attributable risk, however, this factor could account for no more than 16 percent of the cases . CONCLUSIONS . This study provides evidence for an increase in the incidence of hemolytic uremic syndrome, which is probably related to an increased incidence of E . coli O157:H7 infections . Hemolytic uremic syndrome has become an important pediatric and public health problem.

J Clin Microbiol, 1990 Oct, 28(10), 2165 - 8
Rapid biochemical test to identify verocytotoxin-positive strains of Escherichia coli serotype O157; Thompson JS et al.; Fluorogenic procedures were used with the substrate 4-methylumbelliferyl-beta-D-glucuronide (MUG) to identify Escherichia coli . Most strains produced beta-glucuronidase and, thus, were MUG positive . A 20-min procedure was developed to detect glucuronidase activity in 1,295 bacterial cultures, representing 23 genera, of strains that were isolated from clinical specimens . Very few organisms other than E . coli were MUG positive . Of 682 E . coli strains that were isolated, 630 (92.4%) were MUG positive . When an additional 188 E . coli serotype O157 isolates were examined, 155 E . coli O157:H7, 10 E . coli O157:H-, and 1 E . coli O157:H (rough) isolate were MUG negative . All 166 cultures were verocytotoxin positive . Of the remaining 22 E . coli O157 isolates, 2 isolates were O157:H-, 1 isolate was O157:H (rough), and 19 isolates were other H types (H6, H16, H19, H25, H42, and H45); these 22 isolates were MUG positive . All 22 cultures were verocytotoxin negative . The rapid MUG procedure can be used to predict verocytotoxin-positive isolates of E . coli O157; that is, there is a very good likelihood that MUG-negative E . coli O157 isolates are verocytotoxin positive.

Postgrad Med, 1990 Oct, 88(5), 135 - 6, 139-42
Hemolytic-uremic syndrome in children . A serious hazard of undercooked beef; Robson WL et al.; Hemolytic-uremic syndrome is the leading cause of acute renal failure in childhood . Its incidence in North America is increasing . Escherichia coli O157:H7 is the most common infectious trigger and is spread by contaminated beef products as well as from person to person . Antibiotics or antidiarrheal medications should not be used in the treatment of E coli hemorrhagic colitis or hemolytic-uremic syndrome . Mortality in children with the syndrome has fallen to less than 10% in North America, largely because of careful attention to nutrition, maintenance of a normal fluid and electrolyte balance, and careful monitoring . Education and emotional support of the family are important aspects of the treatment program.

Am J Epidemiol, 1990 Aug, 132(2), 239 - 47
A statewide outbreak of Escherichia coli O157:H7 infections in Washington State; Ostroff SM et al.; In November 1986, a statewide outbreak of Escherichia coli O157:H7 infections in Washington State was identified after a physician in an eastern Washington community hospitalized three patients with hemorrhagic colitis which progressed to thrombotic thrombocytopenic purpura . Epidemiologic investigation identified 37 cases in this community and linked the illnesses to a local restaurant which had served ground beef that was the suspected initial vehicle of transmission . The plasmid profile and toxin production pattern (Shiga-like toxin II alone) of the outbreak strain provided a unique strain marker . E . coli O157:H7 infections caused by this strain were simultaneously seen in other parts of the state among nursing home residents and in patients with the hemolytic-uremic syndrome, and an increase in sporadic cases of hemorrhagic colitis was noted at a Seattle health maintenance organization . It is suspected that a contaminated product, probably ground beef distributed statewide, was the common source . Tracing of this meat led to farms where rectal swabs from six (1%) of 539 cattle tested yielded E . coli O157:H7, although the plasmids and toxin production patterns of these isolates differed from the human outbreak strain . Introduction of a single strain of E . coli O157:H7 has the potential to cause widespread concurrent outbreaks . Such outbreaks are likely to escape recognition until heightened screening and surveillance for E . coli O157:H7 is established.

Infection, 1990 Jul-Aug, 18(4), 204 - 9
Vero cytotoxin-producing strains of Escherichia coli in children with haemolytic uraemic syndrome and diarrhoea in Czechoslovakia; Sramkova L et al.; The presence of verotoxin-producing strains of Escherichia coli (VTEC) was examined in six children with haemolytic uraemic syndrome and one child with haemorrhagic colitis . Stools were screened for strains of serogroup O157 on sorbitol-MacConkey agar for VTEC of other serogroups by serotyping . Verotoxin (VT) was tested on Vero cell monolayers: the antigenic variant of VT was assessed by neutralization experiments . Strains producing verotoxin 1 or verotoxin 2 or both were detected in the stools of all seven children . Three strains belonged to serogroup O157 (two of them to serotype O157:H7, one was non-motile) and another five belonged to serogroups O26 (two strains), O1, O5 and O18 . The faeces of five children available for testing contained free VT . Production of VT was also examined retrospectively in 32 E . coli strains of serotype O26:H11 isolated from children with diarrhoea; eight (25%) of them produced moderate to high levels of verotoxin 1 despite several years storage in vitro . In conclusion, VTEC including strains of serogroup O157 seem to be an important cause of haemolytic uraemic syndrome, haemorrhagic colitis and diarrhoea in children in Czechoslovakia.

Infect Immun, 1990 May, 58(5), 1223 - 31
Influence of the 60-megadalton plasmid on adherence of Escherichia coli O157:H7 and genetic derivatives; Toth I et al.; The adherence of enterohemorrhagic Escherichia coli serotype O157:H7 and various genetic derivatives to Henle 407 intestinal and HEp-2 epithelial cell lines was examined by light and electron microscopy . The parent outbreak strain, 7785, harbors a 60-megadalton serotype-specific plasmid designated pO157 and adhered to both cell lines, as determined by light microscopy . A plasmidless derivative, 2-45, showed reduced adherence to both cell lines . After being labeled with Tn801, pO157 was transformed into E . coli C600, E . coli HB101, and E . coli GH42, and back into 2-45 . Both E . coli C600 and HB101 transformants adhered weakly; full adherence was restored to the 2-45(pO157::Tn801) transformant . Transmission electron microscopy (EM) demonstrated the intimate attachment of HB101(pO157::Tn801) to Henle 407 cells which formed cuplike structures and areas of possible actin polymerization adjacent to adhering bacterial cells; scanning EM further extended these observations . EM studies of E . coli O157:H7 strains were hampered by extensive intestinal cell damage, presumably due to the action of Shiga-like toxins . EM also demonstrated that 7785 and its plasmidless derivative 2-45 were piliated and that no pili were apparent on HB101(pO157::Tn801) or GH42//(pO157::Tn801) . The plasmid pO157 appears to modify the eucaryotic cell adherence of E . coli O157:H7 and to confer that adherence on E . coli HB101 through surface structures other than pili . These findings, when compared with other published reports, also suggest similarities between enterohemorrhagic and enteropathogenic E . coli adherence properties.

Infect Immun, 1990 May, 58(5), 1391 - 5
Antigenic relationships of the lipopolysaccharides of Escherichia hermannii strains with those of Escherichia coli O157:H7, Brucella melitensis, and Brucella abortus; Perry MB et al.; Clinical isolates of Escherichia hermannii which showed serological cross-reaction with polyclonal antisera to the O-polysaccharide portion of the lipopolysaccharide of E . coli O157 strains and with antisera to the O antigens of Brucella abortus and B . melitensis were found by chemical and nuclear magnetic resonance analyses to have lipopolysaccharide O chains composed of linear polymers containing 1,2- and 1,3-linked 4-acetamido-4,6-dideoxy-alpha-D-mannopyranosyl (alpha-D-Rhap4NAc) residues . Two O-antigen structures were identified; each had an unbranched pentasaccharide repeating unit, and one was composed of three 1,2- and two 1,3-linked alpha-D-Rhap4NAc residues and the other had two 1,2- and three 1,3-linked alpha-D-Rhap4NAc residues . The above-described cross-serological reactivities, which have led to false-positive identifications, are related to the common occurrence of epitopes involving the presence of N-acyl derivatives of 4-amino-4,6-dideoxy-D-mannopyranosyl residues in the O-polysaccharide portions of the respective lipopolysaccharides of the organisms . Strains of E . hermannii which did not show serological cross-reactions with E . coli O157 and Brucella antisera were found to have unique lipopolysaccharide O chains devoid of D-Rhap4NAc residues, demonstrating the existence of serotypes of E . hermannii that are distinct on the basis of their lipopolysaccharide components.

J Gen Microbiol, 1990 Apr, 136 ( Pt 4), 779 - 86
Attaching and effacing lesions in vivo and adhesion to tissue culture cells of Vero-cytotoxin-producing Escherichia coli belonging to serogroups O5 and O103; Hall GA et al.; Certain isolates of Escherichia coli from humans and animals with enteric disease attach to enterocytes and cause 'attaching and effacing' (AE) lesions . E . coli strain S22-1, serotype O103:H2, isolated from a child with diarrhoea, contained two plasmids; one of these (pDEP12) hybridized with the CVD419 DNA probe derived from a plasmid found in E . coli O157:H7 and associated with expression of fimbriae and ability to adhere to Intestine 407 cells . Strain S102-9, serotype O5:H-, isolated from a calf with dysentery, contained six plasmids, one of which also hybridized with the CVD419 probe . Loss of pDEP12 coincided with reduced adhesion to HEp-2 or Intestine 407 cells cultured in vitro; reintroduction of this plasmid restored adhesiveness . Loss of the plasmid in strain S102-9 that hybridized with the CVD419 probe did not cause a decrease in adhesion . Accumulations of actin were seen in vitro in the fluorescence actin staining (FAS) test of strains S22-1, S102-9 and their derivatives, irrespective of the plasmid content of these strains or the prevalence of attached bacteria . Strain S22-1 and its plasmidless derivative caused AE lesions of equal severity in experimentally infected gnotobiotic piglets; piglets inoculated with an isolate from a healthy human or pig did not develop these lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

J Clin Microbiol, 1990 Apr, 28(4), 651 - 3
Phenotype and genotype of Escherichia coli isolated from pigs with postweaning diarrhea in Hungary; Nagy B et al.; A total of 205 Escherichia coli isolates from 88 diarrheal weanling (4- to 10-week-old) pigs from 59 farms were tested by slide agglutination for K88, K99, F41, and 987P antigens . K88 antigen was detected in 61% of the isolates representing 60% of the pigs and 56% of the farms . K88 antigen was associated with serogroup O149 and 91% of the K88+ isolates . K99, F41, and 987P were not detected . Of the K88- isolates, 70 were additionally tested by colony hybridization with DNA probes for adherence factors K88, K99, 987P, and F41 and for enterotoxin genes STaP, STaH, STb, and LT and by Vero cell assay for verotoxins (VT) . The 70 K88- isolates could be divided into three categories: LT-, VT-, STaP+, and/or STb+ (34 isolates); LT-, STaP+, STb+, and/or VT+ (17 isolates); and nontoxigenic (19 isolates) . Only one of the K88- isolates carried a known adherence factor (987P) detectable with DNA probes . Most of the STaP+ and STb+ isolates belonged to O groups O141, O147, and O157 . All but 1 of the 17 VT+ isolates belonged to O groups O138, O139, O141, and O149 . Only three of the VT+ strains were isolated from pigs with edema disease . We concluded that 73% of the K88- isolates had the capability to produce enterotoxins or VT that could have contributed to weanling pig diarrhea.

Infect Immun, 1990 Apr, 58(4), 860 - 7
Characteristics of binding of Escherichia coli serotype O157:H7 strain CL-49 to purified intestinal mucin; Sajjan SU et al.; Purified rat intestinal mucin was used as a model mucin to study the binding of Escherichia coli serotype O157:H7, a human pathogen associated with outbreaks of hemorrhagic colitis and hemolytic uremic syndrome . Of six O157:H7 strains, only one strain (designated CL-49) bound to rat (and other) intestinal mucins by a specific and saturable process . Binding was observed only after the bacteria were serially passaged to promote the expression of type 1 pili (fimbriae) . Several other type 1-piliated E . coli strains, however, did not bind to mucin . Binding of E . coli CL-49 was inhibited by D-mannose and short oligomannosyl derivatives, particularly Man-alpha-1,3-Man, Man-alpha-1,2-Man, and Man-alpha-1,3-Man-beta-1,4-N-acetylglucosamine . Other inhibitors of binding included p-nitrophenol (10(-4) M), heating at 60 degrees C (to remove pili), an antibody to type 1 pili, and purified type 1 pili of E . coli CL-49 used as hapten inhibitors . A comparison of the hydrophobicity of piliated E . coli CL-49 with other type 1-piliated E . coli strains indicated that the former strain was much more hydrophobic than the others . These findings indicate that highly purified intestinal mucins possess specific mannosyl receptor sites for bacterial type 1 pili on E . coli CL-49, but that strong hydrophobic interactions between the mucin and the pili stabilize the mannose-dependent binding process . We speculate that the mucin receptors for type 1 pili reside in oligosaccharides of the 118-kilodalton "link" glycopeptide, since this is the only mucin component known to contain mannose.

Eur J Epidemiol, 1990 Mar, 6(1), 102 - 4
Isolation in Italy of a verotoxin-producing strain of Escherichia coli O157:H7 from a child with hemolytic-uraemic syndrome; Caprioli A et al.; Verotoxin-producing Escherichia coli O157:H7 was isolated for the first time in Italy from a child with hemolytic-uremic syndrome and his asymptomatic sister . Both parents remained asymptomatic, and neither had evidence of this infection . The source of the infection was not identified, but the children had eaten ground beef during the 15 days prior to the onset of symptoms.

S Afr J Surg, 1990 Mar, 28(1), 28 - 9
Escherichia coli O157:H7 haemorrhagic colitis . Report of the first South African case; Browning NG et al.; Escherichia coli O157:H7, although recognised 15 years ago, has only become a significant pathogen since 1982 when two outbreaks of haemorrhagic colitis due to this organism were described in the USA . Since then, numerous such outbreaks have been reported . Recent experience with a patient presenting with E . coli O157:H7-induced haemorrhagic colitis is described . The main features, pathological findings and investigations are described and the principles of management outlined.

J Dairy Sci, 1990 Feb, 73(2), 333 - 41
Effect of severity of systemic signs during the acute phase of experimentally induced Escherichia coli mastitis on milk production losses; Lohuis JA et al.; The objectives were to describe the systemic signs during the acute phase of experimental Escherichia coli mastitis and to relate these with losses in milk production during the reconvalescent period . Eleven cows, 20 to 30 d postpartum, were inoculated with 10(4) cfu of E . coli O157 in rear quarters . Heart rate, rectal temperature, frequency and amplitude of rumen contractions, plasma Zn and Fe concentrations, and counts of E . coli were used to monitor severity of disease during the acute phase . Areas under curves of clinical parameters, plasma Zn and Fe concentrations, and counts of E . coli were calculated during 36, 120, and 125 h postinoculation, respectively . Areas under curves of milk production were calculated during 21 d postinoculation . Losses in total daily milk production were related positively with areas under curves of heart rate, rumen amplitude, counts of E . coli in secreta from inoculated quarters, and plasma Zn and Fe concentrations . These parameters may prove suitable to establish an accurate prognosis for returning to milk production cows suffering from acute or peracute E . coli mastitis and to evaluate efficacy of drugs in experimental mastitis.

Eur J Pediatr, 1990 Jan, 149(4), 259 - 60
Escherichia coli O157:H7 infections associated with perforated appendicitis and chronic diarrhoea; Cimolai N et al.; Two unique associations of disease with Escherichia coli O157:H7 are presented . These cases broaden the spectrum of disease associated with this organism which currently includes bloody and non-bloody diarrhoea, haemolytic-uraemic syndrome, and thrombotic thrombocytopenic purpura.

J Infect Dis, 1989 Dec, 160(6), 994 - 8
Toxin genotypes and plasmid profiles as determinants of systemic sequelae in Escherichia coli O157:H7 infections; Ostroff SM et al.; In 1987, 93 Escherichia coli O157:H7 isolates were collected during routine surveillance for this pathogen in the state of Washington . Toxin genotypes and plasmid profiles were correlated with the clinical sequelae of illness in 88 of the 93 patients from whom these strains were isolated . Thirteen plasmid patterns were observed among the 88 tested isolates; four patterns accounted for 82% of the isolates . Genetic probing for Shiga-like toxins (SLT) I and II demonstrated the presence of both genes in 67 (76%), SLT I alone in three (3%), and SLT II alone in 18 (20%) . The hemolytic uremic syndrome or thrombotic thrombocytopenic purpura developed in seven (39%) of 18 patients infected with isolates having only the SLT II gene, while these complications occurred in only four (6%) of 70 patients infected with isolates having the other two genotypes (relative risk, 6.8; 95% confidence interval, 1.9, 26.4) . This study shows that E . coli O157:H7 isolates systematically collected from a single geographic region over a defined time period exhibit considerable diversity in plasmid content and toxin genotype and that the toxin genotype of the infecting strain may influence the risk of developing microangiopathic sequelae.

J Infect Dis, 1989 Nov, 160(5), 858 - 64
Risk factors for Escherichia coli O157:H7 infection in an urban community; Bryant HE et al.; Outbreaks of Escherichia coli O157:H7 have been attributed to meat or meat products, particularly ground meat, and to unpasteurized dairy products . However, the risk factors for sporadic cases have not been clearly delineated . Study data were collected by using a self-administered dietary and historical questionnaire on all patients whose history included bloody diarrhea and who attended one of the participating emergency departments . Designation as "case" or "control" occurred after stool culture results were known, eliminating the possibility for recall bias common to this type of study . Cases (E . coli O157:H7-positive) were further matched with one diarrheal and one healthy community control, and more detailed information on food preparation practices and other data were then taken . Of 266 presentations of bloody diarrhea, 103 (38.7%) were due to E . coli O157:H7 . Unmatched analyses with bloody diarrheal controls revealed a seemingly lower risk for E . coli O157:H7 infection in fast food restaurant patrons . No increased risk could be detected for ground meat consumption despite adequate study power, although an association between ingestion of undercooked meat and infection (odds ratio = 3.5, P less than .05) was found when community controls were used . Proper food cooking (and handling) rather than the avoidance of particular food products is the preventive measure of choice.

J Clin Microbiol, 1989 Nov, 27(11), 2559 - 64
Close association of verotoxin (Shiga-like toxin) production with enterohemolysin production in strains of Escherichia coli; Beutin L et al.; Sixty-four verotoxin-producing (VT+) Escherichia coli strains were analyzed for VT1- and VT2-specific DNA sequences and for production of hemolysin . Strains of human origin were of the following serotypes: O157:H7 or H-, O111:H8 or H-, O26:H11, O114:H4, and rough:H7 . Strains of serotypes O157:H7, O113:H21, O116:H21, and rough:H- were from cattle, while those of serotype O139:K12:H1 were from pigs . All 64 isolates carried either VT1 or VT2 or both genes . Sixty of the strains (93.8%) were hemolytic (Hly+) . The three O139:K12:H1 strains examined produced alpha-hemolysin, as shown by their reaction with the alpha-hemolysin-specific monoclonal antibody h2A and by DNA hybridization with an alpha-hly gene probe . The remaining 57 Hly+ strains (95%) produced a different type of hemolysin (enterohemolysin), which is genetically and serologically unrelated to alpha-hemolysin . The two types of hemolysin are further distinguished by the appearance of the lysis zone on blood agar and by the time interval for the detection of hemolysis . In contrast to alpha-hemolysin, enterohemolysin can be detected only on blood plates containing washed erythrocytes . The frequent association of enterohemolysin with verotoxin production (89%) makes it useful as an epidemiological marker for rapid and simple detection of potential VT+ E . coli.

J Med Microbiol, 1989 Nov, 30(3), 219 - 26
Production and characterisation of monoclonal antibodies to Verotoxins 1 and 2 from Escherichia coli of serotype O 157:H7; Padhye VV et al.; Fourteen hybridoma cell lines were isolated that produced monoclonal antibodies (MAbs) to purified Verotoxins 1 and 2 (VT1, VT2) of Escherichia coli of serotype O157:H7 . Of these MAbs, eight were obtained by immunisation of BALB/c mice with purified VT1, and six were obtained from BALB/c mice immunised with purified VT2 . With the exception of MAb 1C5, with a heavy chain of IgG2b class, antibodies produced from mice immunised with heat-treated toxin were of IgM class . MAbs produced from mice immunised with heat-treated VT1 or VT2 reacted with both verotoxins in ELISA, and Western-blot analysis revealed that they reacted with subunit A and the A1 fragment of nicked subunit A of both toxins, but not with subunit B; furthermore, none of them neutralised Vero cytotoxicity or mouse lethality of either toxin . In contrast, MAbs produced from mice immunised with heat-treated and formalin-treated VT1 reacted in Western blots with subunits A and B of VT1 and subunit A, but not subunit B, of VT2, reacted in ELISA with VT1 only, and neutralised Vero cytotoxicity and mouse lethality of VT1 but not of VT2 . Results indicate the existence of a common epitope on subunit A of VT1 and VT2 that is not responsible for the biological activity of these toxins, and that subunit B is essential for the biological activity of VT1 . MAbs capable of reacting with both verotoxins from E . coli of serotype O157:H7 may be useful reagents for screening bacterial isolates capable of producing one or both of these toxins.

J Clin Microbiol, 1989 Sep, 27(9), 1973 - 8
Purification of an Escherichia coli serogroup O157:H7 verotoxin and its detection in North American hemorrhagic colitis isolates; Dickie N et al.; Verotoxin (VT), which is immunologically unrelated to VT1 (Shiga-like toxin I), was purified from the culture filtrate of Escherichia coli hemorrhagic colitis serogroup O157:H7 strain 3657 by copper ion chelate affinity chromatography followed by anion-exchange chromatography . The isoelectric point by sucrose density gradient isoelectric focusing was 5.0, the molecular weight by gel filtration on Superose 12 was about 60,000, and the 50% cytopathic dose for Vero cells was about 1 pg . This toxin was found by immunological methods to be the predominant VT in E . coli O157 isolates associated with illness in North America, with 38 of 42 strains tested producing this toxin, 20 in combination with VT1 . VT from strain 3657 is immunologically identical to the described Shiga-like toxin II (VT2) of E . coli strains (from the United States) K-12(pEB1) and C600(933W) but only partially related to VT of strain E32511 (from the United Kingdom), the first to be named VT2.

J Gen Microbiol, 1989 Aug, 135 ( Pt 8), 2307 - 18
Comparison of Vero-cytotoxin-encoding phages from Escherichia coli of human and bovine origin; Rietra PJ et al.; Phages encoding production of Vero cytotoxins VT1 or VT2 were isolated from strains of Escherichia coli of human and bovine origin . Two human strains of serotype O157: H7 produced both VT1 and VT2 and each carried two separate phages encoding either VT1 or VT2 . The phages were morphologically similar to each other and to a VT2 phage previously isolated from a strain of serotype O157: H-; all had regular hexagonal heads and short tails . The phages had similar genome sizes and DNA hybridization and restriction enzyme digestion showed that the DNAs were very closely related . This contrasts with another report that one of the strains tested (933) released two clearly distinguishable phages separately encoding VT1 and VT2 . The O157 phages differed from a VT1 phage isolated from a bovine E . coli strain belonging to serotype O26: H11 and from the reference VT1 phage isolated previously from a human strain, H19, of serotype O26: H11 . The two O26 phages were morphologically similar with elongated heads and long tails . They had similar genome sizes and DNA hybridization indicated a high level of homology between them . Hybridization of an O157 phage DNA probe to DNA of the O26 phages, and vice versa, showed there was some cross-hybridization between the two types of phage . A phage from a bovine strain of serotype O29: H34 had a regular hexagonal head and short tail resembling those of the O157 phages . The DNA was distinguishable from that of all the other phages tested in restriction digest patterns but hybridized significantly to that of an O157 phage . Hybridization of the phage genomes with VT1 and VT2 gene probes showed that sequences encoding these toxins were highly conserved in the different phages from strains belonging to the three serogroups.

Epidemiol Infect, 1989 Aug, 103(1), 83 - 95
Properties of Vero cytotoxin-producing Escherichia coli of human and animal origin belonging to serotypes other than O157:H7; Dorn CR et al.; Eight non-O157:H7 Vero cytotoxin (VT)-producing Escherichia coli (VTEC) strains isolated from ill persons and nine bovine and lamb strains of serogroups matching the human strains, were characterized for various properties known to be associated with E . coli virulence . Five different serogroups were represented: O5, O55, O103, O111 and O153 . The bovine and lamb strains produced VT1, while 3 human strains produced VT1, 3 produced VT2 and 2 were positive for both VT1 and VT2 . The strains were non-haemolytic on horse blood agar, did not produce either heat stable toxin A (STA) or heat labile toxin (LT), and were noninvasive . The CVD419 probe which has been proposed to identify enterohaemorrhagic E . coli (EHEC) hybridized with all of the O5 and O103 strains, none of the O55 and O153 strains, and 3 of the 4 O111 strains . The strains carried several different sized plasmids and hybridization of Southern blots with the CVD419 probe identified plasmids ranging in size from 42 x 10(6) to 90 x 10(6) . The strains did not hybridize with the enteroadherence factor (EAF) probe derived from an enteropathogenic strain and associated with the ability to give localized adherence to HEp-2 cells . Nevertheless five of the strains adhered in a localized pattern to HEp-2 cells and Intestine 407 cells . Adhesion to either HEp-2 or Intestine 407 cells did not correlate with hybridization with the CVD419 probe or haemagglutinating properties.

Epidemiol Infect, 1989 Aug, 103(1), 73 - 81
Phage-typing of Vero-cytotoxin (VT) producing Escherichia coli O157 isolated in the United Kingdom; Frost JA et al.; Vero-cytotoxin (VT) producing Escherichia coli serogroup O157 have been isolated from patients with diarrhoea, haemorrhagic colitis (HC) and haemolytic uraemic syndrome (HUS) . A phage-typing scheme developed in Canada has been used to type 155 VT+ E . coli O157 serogroup isolated from sporadic infections in the UK since 1983, and 48 strains from HC or HUS outbreaks . Twelve phage types were identified of which three, types 49, 51 and 52, have not been found in North America . All strains carried a 60 x 10(6) plasmid and most VT1+VT2+ strains also had a 5 x 10(6) plasmid coding for colicin D production . The majority of strains producing both VT1 and VT2 belonged to phage type 1, or the related types 4, 8 and 14 . Most strains producing only VT2 belonged to types 2 or 49 . Four outbreaks were included in the survey . Three had strains of a single phage type while strains from the fourth outbreak were more variable . The distribution of phage types throughout the UK showed no marked geographical variations.

J Clin Microbiol, 1989 Jun, 27(6), 1180 - 6
Evaluation of oligonucleotide probes for identification of shiga-like-toxin-producing Escherichia coli; Karch H et al.; Four synthetic oligonucleotide probes representing different regions of the Shiga-like toxin I (SLT-I) structural genes and one oligonucleotide derived from the SLT-II gene of Escherichia coli serotype O157:H7 strain 933 were examined for the identification of E . coli strains that produce cytotoxins for Vero or HeLa cells . E . coli strains that synthesize SLT-I alone or O157:H7 isolates that coexpress SLT-I and SLT-II hybridized with all four probes that were complementary to the SLT-I genes, suggesting that they have toxin genes with great homology in all the regions examined . In colony hybridization tests, these oligonucleotide probes did not react with E . coli strains that were nontoxigenic for Vero cells or that produced cytotoxins belonging to the SLT-II family . The probe derived from the slt-IIA gene distinguished E . coli strains that produced SLT-II alone from SLT-I-producing strains and hybridized to all E . coli O157:H7 strains that produced both SLT-I and SLT-II . Using two of these oligonucleotide probes that were complementary to slt-IA or slt-IIA sequences, we identified 50 of 52 cytotoxin-producing strains, whereas none of 416 nontoxigenic E . coli strains was reactive . The colony blot hybridization with the oligonucleotide probes described here can serve as a specific and sensitive test with potential diagnostic value.

Clin Invest Med, 1989 Jun, 12(3), 194 - 200
Adherence of vero cytotoxin-producing Escherichia coli serotype O157:H7 to isolated epithelial cells and brush border membranes in vitro: role of type 1 fimbriae (pili) as a bacterial adhesin expressed by strain CL-49; Durno C et al.; Vero cytotoxin-producing Escherichia coli of the serotype O157-:H7 have recently been associated with sporadic cases and outbreaks of hemorrhagic colitis and with the hemolytic-uremic syndrome . E . coli O157:H7 strains adhere to human epithelial cells in tissue culture and to the intestine of orally infected rabbits . To determine whether E . coli O157:H7 adhere to normal post-natal human epithelial cells, we isolated buccal epithelial cells from healthy adult volunteers and isolated ileal enterocytes and colonocytes from histologically normal margins of surgical resection specimens . Apical brush border membranes from the distal ileum and colonocytes of the proximal colon were also prepared from post-weaning rabbits . Binding of five E . coli O157:H7 strains to epithelial cells and brush border membranes was determined by two complementary methods: firstly, under phase contrast microscopy and secondly, by quantitating adherence of radiolabelled bacteria to substrates that were bound to polystyrene microtiter wells . Under incubation conditions used previously to document in vitro adherence of other diarrheagenic E . coli, only the one type-1 fimbriated E . coli O157:H7 strain, designated CL-49, adhered to isolated human and rabbit epithelial cells . In contrast, binding of 4 non-type-1 fimbriated O157:H7 strains could not be demonstrated . Adherence of the fimbriated E . coli O157:H7 strain was saturable and varied with pH and temperature of the incubation medium . Adherence of bacteria to rabbit ileal brush borders was mediated by binding of bacteria to alpha-linked mannosyl residues present on surface glycoproteins.(ABSTRACT TRUNCATED AT 250 WORDS)

Infect Immun, 1989 Apr, 57(4), 1339 - 42
Edema disease-like brain lesions in gnotobiotic piglets infected with Escherichia coli serotype O157:H7; Francis DH et al.; Gnotobiotic piglets inoculated with Escherichia coli serotype O157:H7 strains that produced Shiga-like toxin II developed brain lesions similar to those observed in edema disease of swine, including arteriolar necrosis and malacia . Loss of ability to produce Shiga-like toxin II resulted in loss of ability to cause brain lesions.

J Clin Microbiol, 1989 Feb, 27(2), 285 - 90
Serum antibodies to Escherichia coli serotype O157:H7 in patients with hemolytic uremic syndrome; Chart H et al.; Sera from 13 patients with hemolytic uremic syndrome (HUS) and 8 healthy control subjects were examined for antibodies specific for bacterial antigens of Eschericia coli serotype O157:H7 . Bacterial components, including outer membrane proteins (OMPs), lipopolysaccharide (LPS), and flagella, were reacted with sera by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by immunoblotting and by enzyme-linked immunosorbent assay . All 13 serum samples from HUS patients contained high-titered antibodies of the immunoglobulin M class against O157 LPS and some OMPs . These same sera reacted weakly with some of the major OMPs, but not the LPS, of non-O157 strains of E . coli . Sera from patients did not contain antibodies to non-O157 LPS or H7 flagella . The possibility of using E . coli serotype O157 LPS in an enzyme-linked immunosorbent assay for the routine diagnostic testing of sera from HUS patients for evidence of O157:H7 infection is discussed.

Gastrointest Radiol, 1989 Fall, 14(4), 341 - 4
Radiologic findings in hemorrhagic colitis due to Escherichia coli O157:H7; Shortsleeve MJ et al.; Hemorrhagic colitis due to Escherichia coli O157:H7 is a distinct clinical entity characterized by abdominal pain, watery diarrhea progressing to bloody diarrhea, and little or no fever . It has been reported to have a mortality as high as 31% . This form of colitis is not described in the radiologic literature . This paper describes the radiographic findings, and stresses the need for radiologists to be familiar with the disease in order to assist in early diagnosis . Key clinical and epidemiological features are reviewed.

Vet Microbiol, 1988 Dec, 18(3-4), 297 - 311
Production of toxins by Escherichia coli strains isolated from calves with diarrhoea in galicia (north-western Spain); Blanco J et al.; A total of 289 Escherichia coli colonies isolated from 78 diarrhoeic calves were studied for production of heat-labile (LT) and heat-stable (STa) enterotoxins, verotoxin (VT), cytotoxic necrotizing factor (CNF) and K99 antigen, and they were serotyped . Production of STa was detected in a single strain possessing both K99 and F41 antigens; the serotype was 09:K (A) 35 . LT-producing strains were not detected . From 16 (20.5%) calves, 51 VT-producing colonies of E . coli were isolated . Production of the necrotic factor was detected in 33 E . coli colonies isolated from 14 (17.9%) calves . Serotype was a useful marker for production of VT and CNF . Among the 51 VT-producing colonies, 24 were untypable and the remainder belonged to serotypes O2:K?, O103:K--, O104:K?, O128:K?, O153:K-- and O157:K--:H7 . Four of the 33 CNF-producing colonies were untypable and the majority of the remaining colonies belonged to serotypes O15:K14, O78:(K80), O123:K-- and O139:K-- . Both VT and CNF were lethal for mice, but only CNF showed necrotizing reaction in rabbit skin . Our results indicate that VT-producing and CNF-producing E . coli strains are frequently isolated from diarrhoeic calves and that according to the serotypes exhibited, some of them might be considered potential pathogens for humans . The role of VT-producing and CNF-producing strains in calf diarhoea remains to be established.

J Clin Microbiol, 1988 Nov, 26(11), 2248 - 9
Inhibition of Escherichia coli serotype O157:H7 by bromthymol blue; Gubash SM et al.; Bromthymol blue, at a concentration of 0.1% in tryptose-glucose broth, inhibited growth of 98.4% of Escherichia coli serotype O157:H7 isolates but only 0.8% of E . coli non-O157:H7 isolates after an overnight incubation at 44.5 degrees C, but not 35 degrees C . The inhibition was dependent on temperature, density of inoculum, bromthymol blue concentration, time of incubation, and composition of the medium . Compared with serologic typing, the inhibition had sensitivity, specificity, predictive values of the positive and negative tests, and overall agreement between the two tests of 98.4, 99.2, 98.4, 99.2, and 98.9%, respectively . The inhibition could be useful as a presumptive test to identify E . coli isolates of serotype O157:H7, especially in laboratories that do not have serotyping capabilities.

Pediatr Nephrol, 1988 Oct, 2(4), 409 - 14
A family outbreak of hemolytic-uremic syndrome associated with verotoxin-producing Escherichia coli serotype O157:H7; Karmali MA et al.; All five siblings (three boys and two girls, aged 1.5-9 years) in a family developed hemolytic-uremic syndrome associated with verotoxin-producing Escherichia coli O157:H7 at a lakeside vacation cottage during the fall of 1985 . All five were hospitalized and made a full recovery . Both parents remained asymptomatic, and neither had evidence of this infection . In four children who were investigated prospectively, free verotoxin was still detectable in the stools for between 3 and 7 weeks . The prodromal diarrheal illness in the children occurred over a 10-day period . The epidemic curve was consistent with a point-source outbreak, but continuous exposure or person-to-person transmission could not be ruled out . The source of the infection was not identified.

Appl Environ Microbiol, 1988 Oct, 54(10), 2536 - 40
Rapid hydrophobic grid membrane filter-enzyme-labeled antibody procedure for identification and enumeration of Escherichia coli O157 in foods; Todd EC et al.; An O-antigen-specific monoclonal antibody, labeled by horseradish peroxidase-protein A, was used in a hydrophobic grid membrane filter-enzyme-labeled antibody method for rapid detection of Escherichia coli O157 in foods . The method yielded presumptive identification within 24 h and recovered, on average, 95% of E . coli O157:H7 artificially inoculated into comminuted beef, veal, pork, chicken giblets, and chicken carcass washings . In food samples from two outbreaks involving E . coli O157:H7, the organism was isolated at levels of up to 10(3)/g . The lower limit of sensitivity was 10 E . coli O157 per g of meat . Specific typing for E . coli O157:H7 can be achieved through staining with labeled H7 antiserum or tube agglutination.

J Clin Pathol, 1988 Oct, 41(10), 1099 - 103
Cerebral infection with Escherichia coli O157:H7 in humans and gnotobiotic piglets; Tzipori S et al.; Escherichia coli O157:H7 was isolated from a fatal case of haemorrhagic colitis with haemolytic uraemic syndrome and neurological symptoms . This strain induced diarrhoea and neurological symptoms including incoordination, ataxia, and convulsions in piglets after oral inoculation . Similar neurological signs were seen in piglets inoculated intraperitoneally with bacterial extracts containing a shiga-like toxin that is elaborated by the bacteria . Histological examination of the brains from these piglets showed vascular damage and small infarcts confined to the cerebellum . Comparable lesions were also seen in the brain of the child from whom E coli O157:H7 was isolated . We suggest that the cerebral changes in the piglets and in the patient were caused by the shiga-like toxin elaborated by E coli O157:H7 . The shiga-like toxin is thought to cause neurological abnormalities by damage to cerebral blood vessels rather than by a direct effect on the neurones.

Microb Pathog, 1988 Sep, 5(3), 215 - 21
Purified verotoxins of Escherichia coli O157:H7 decrease prostacyclin synthesis by endothelial cells; Karch H et al.; Two immunologically distinct verotoxins purified from Escherichia coli C600, lysogenized with distinct temperate phages from E . coli strain 933 of serotype O157:H7, were compared by SDS-PAGE and different biological assays . The two toxins termed verotoxin 1 (VT1) and verotoxin 2 (VT2) differing in molecular weight exhibited similar biological activities . Both preparations were toxic for HeLa cells and lethal for mice . Epidemiological evidence of verotoxinogenesis in some cases of hemolytic-uremic syndrome (HUS) and the recent observations of inadequate prostacyclin production by endothelial cells associated with HUS prompted us to study the effect of purified verotoxins on prostacyclin synthesis in rat aortic tissue . Our results demonstrate a significant reduction of prostacyclin by both toxins at picomolar levels . The suppression of prostacyclin release by a lower concentration of VT2 as compared with VT1 reflects the relative potencies of these toxins in HeLa cell toxicity and mouse lethality . The results suggest an effect of verotoxins on endothelial cells and support the concept of these toxins as virulence factors in E . coli.

Microb Pathog, 1988 Sep, 5(3), 189 - 95
Isolation and some properties of A and B subunits of Vero toxin 2 and in vitro formation of hybrid toxins between subunits of Vero toxin 1 and Vero toxin 2 from Escherichia coli O157:H7; Ito H et al.; Purified Vero toxin 2 (VT2) was separated into A and B subunits by treatment with 6 M urea in 0.1 M propionic acid (pH 4.0) . The isoelectric points of the isolated A and B subunits were determined to be 8.1 and 4.1, respectively . The A subunit of the purified VT2 was not nicked, but could be nicked in vitro by trypsin . Biologically active toxin was reconstituted from the isolated A and B subunits of VT2 . Hybrid toxins with biological activity were obtained in vitro from the A subunit of Vero toxin 1 (VT1) and the B subunit of VT2, and from the A subunit of VT2 and the B subunit of VT1 . The hybrid toxins showed similar cytotoxicity to native VT1 and VT2 on Vero cells . The in vitro formations of hybrid toxins were confirmed by polyacrylamide disc gel electrophoresis.

Pediatr Clin North Am, 1988 Jun, 35(3), 485 - 501
Cytotoxin-producing Escherichia coli and the hemolytic uremic syndrome; Cleary TG; Recently, a new class of diarrhea-associated Escherichia coli has been linked to the hemolytic uremic syndrome . The organisms included in this group produce cell-damaging toxins (cytotoxins) related to Shigatoxin made by S . dysenteriae 1 . The most common pathogen in this group is E . coli O157:H7.

J Infect Dis, 1988 Jun, 157(6), 1124 - 33
Genetic evidence of clonal descent of Escherichia coli O157:H7 associated with hemorrhagic colitis and hemolytic uremic syndrome; Whittam TS et al.; Genetic relatedness of 100 strains of Escherichia coli, isolated mostly from patients with hemorrhagic colitis or hemolytic uremic syndrome, was determined for chromosomal genotypes on the basis of allelic variation at 17 enzyme-encoding loci detected by multilocus enzyme electrophoresis . Fifteen of the 17 loci were polymorphic, with an average of 3.5 alleles per locus . Comparison of the observed combinations of alleles among strains revealed 25 distinct multilocus genotypes, which were used to define naturally occurring cell lineages or clones . Cluster analysis of the genotypic data revealed that isolates of serotype O157:H7 fall into a well-defined group of clonal genotypes that share alleles, on average, at 90% of their enzyme loci . The O157:H7 clonal group is only distantly related to other Verotoxin-producing strains belonging to other serotypes of E . coli . The results strongly support the hypothesis that isolates of E . coli O157:H7 obtained from geographically separate outbreaks and sporadic cases of hemorrhagic colitis and hemolytic uremic syndrome belong to a pathogenic clone that occurs throughout North America.

J Med Microbiol, 1988 May, 26(1), 11 - 7
Adherence of Vero cytotoxin-producing Escherichia coli of serotype O157:H7 to human epithelial cells in tissue culture: role of outer membranes as bacterial adhesins; Sherman PM et al.; Escherichia coli of serotype O157:H7 are Vero cytotoxin-producing enteric pathogens that have recently been associated with outbreaks of haemorrhagic colitis, sporadic cases of haemorrhagic colitis and with the haemolytic uraemic syndrome . The organisms demonstrate attaching and effacing binding to the caecum and colon of orally infected gnotobiotic piglets, chickens and infant rabbits . E . coli O157:H7 cells adhere to the surface but do not invade the cytoplasm of human epithelial cell lines in tissue culture . Since outer membranes, lipopolysaccharides and flagella have been identified as bacterial adhesins on other enteric pathogens, we evaluated their roles in the binding of non-fimbriated E . coli O157:H7 to HEp-2 cells . Hyperimmune rabbit antisera were prepared to whole cells, outer membranes and flagella of E . coli O157:H7 . The presence of antibody to homologous antigen was confirmed by dot blot immunoassays . Both antisera and purified outer membrane and flagellar antigens were co-incubated with bacteria and HEp-2 cells to quantitate inhibition of bacterial attachment . Adherence of E . coli O157:H7 to tissue culture cells was inhibited by rabbit antisera raised to whole cells (76.0 +/- 5.6% inhibition compared with bacterial adherence in the presence of pre-immune rabbit serum) and outer membranes (69.2 +/- 3.4% inhibition) . In contrast, inhibition of bacterial attachment to tissue-culture cells was significantly less when two antisera to H7 flagella were co-incubated with E . coli O157:H7 and HEp-2 cells (12.4 +/- 7.6%; 6.0 +/- 3.5% inhibition) . Outer-membrane extracts inhibited adherence to E . coli O157:H7 to HEp-2 cells in a concentration dependent manner whereas isolated flagella and lipopolysaccharide antigens did not inhibit bacterial attachment.(ABSTRACT TRUNCATED AT 250 WORDS)

Ann Inst Pasteur Microbiol, 1988 Mar-Apr, 139(2), 189 - 202
Detection of enteric pathotypes of Escherichia coli by hybridization using six DNA probes; Bohnert MG et al.; A set of 6 DNA probes was tested to evaluate the incidence of various Escherichia coli pathotypes among 540 strains isolated in France from diarrhoeal stools of infants, children and adults . Enterotoxigenic E . coli were detected using 3 gene probes for enterotoxins LT, STaH and STaP . Enteroinvasive E . coli were detected using one DNA probe which specifically hybridizes with bacteria expressing the cell invasion phenotype "INV" . They represented 1.5% and 1.1% of the total, respectively . An SLTI probe which contains the structural gene for the A subunit of Shiga-like toxin I was constructed to detect enterohaemorrhagic E . coli . Among the 5 strains detected, only 1 belonged to serotype O157:H7 . An attempt was made to detect enteropathogenic E . coli (EPEC) using both an EPEC-adherence factor and the above mentioned SLTI probes . Under the experimental conditions, they did not appear to be efficient at detecting this pathotype.

Microb Pathog, 1988 Feb, 4(2), 127 - 35
Inhibition of protein synthesis by a Vero toxin (VT2 or Shiga-like toxin II) produced by Escherichia coli O157:H7 at the level of elongation factor 1-dependent aminoacyl-tRNA binding to ribosomes; Ogasawara T et al.; A Vero toxin (VT2 or Shiga-like toxin II) from Escherichia coli O157:H7 was shown to inhibit protein synthesis in a rabbit reticulocyte lysate, but not in wheat germ or Ercherichia coli lysates . The toxin, VT2, inactivated 60S ribosomal subunits of rabbit reticulocytes . The site of inhibition of protein synthesis by VT2 was shown to be elongation factor 1-dependent aminoacyl-tRNA binding to ribosomes . VT2 did not affect Met-tRNAf binding to ribosomes, non-enzymatic binding of aminoacyl-tRNA to ribosomes, peptide bond formation or translocation.

Appl Environ Microbiol, 1987 Oct, 53(10), 2394 - 6
Isolation of Escherichia coli O157:H7 from retail fresh meats and poultry; Doyle MP et al.; A total of 896 samples of retail fresh meats and poultry was assayed for Escherichia coli serogroup O157:H7 by a hydrophobic grid membrane filter-immunoblot procedure developed specifically to isolate the organism from foods . The procedure involves several steps, including selective enrichment, filtration of enrichment culture through hydrophobic grid membrane filters, incubation of each filter on nitrocellulose paper on selective agar, preparation of an immunoblot (by using antiserum to E . coli O157:H7 culture filtrate) of each nitrocellulose paper, selection from the filters of colonies which corresponded to immunopositive sites on blots, screening of isolates by a Biken test for precipitin lines from metabolites and antiserum to E . coli O157:H7 culture filtrate, and confirmation of isolates as Vero cell cytotoxic E . coli O157:H7 by biochemical, serological, and Vero cell cytotoxicity tests . E . coli O157:H7 was isolated from 6 (3.7%) of 164 beef, 4 (1.5%) of 264 pork, 4 (1.5%) of 263 poultry, and 4 (2.0%) of 205 lamb samples . One of 14 pork samples and 5 of 17 beef samples contaminated with the organism were from Calgary, Alberta, Canada, grocery stores, whereas all other contaminated samples were from Madison, Wis., retail outlets . This is the first report of the isolation of E . coli O157:H7 from food other than ground beef, and results indicate that the organism is not a rare contaminant of fresh meats and poultry.

Microb Pathog, 1987 Jul, 3(1), 21 - 30
Purification and some properties of a Vero toxin from Escherichia coli O157:H7 that is immunologically unrelated to Shiga toxin; Yutsudo T et al.; A cytotoxin to Vero cells (Vero toxin) was purified from Escherichia coli O157:H7 isolated from a patient with hemorrhagic colitis by ammonium sulfate fractionation, DEAE-cellulose column chromatography, repeated chromatofocusing column chromatography and repeated high performance liquid chromatography . About 440 micrograms of purified Vero toxin was obtained from 12 liters of culture with a yield of about 22% . The purified Vero toxin showed similar cytotoxic activity to that of Shiga toxin to Vero cells and killed about 50% of the Vero cells at 1 pg . The activity was lost on heating the toxin at 80 degrees C for 10 minutes, but not at 60 degrees C for 10 minutes . The toxin also showed lethal toxicity to mice when injected intraperitoneally, the LD50 being 1 ng per mouse . The purified Vero toxin consisted of A and B subunits with molecular weights of about 35,000 and 10,700, respectively, which were slightly larger than those of Shiga toxin . On polyacrylamide gel disc electrophoresis, the mobility of the purified Vero toxin differed from that of Shiga toxin . The isoelectric point of the toxin was 4.1, which was also different from that of Shiga toxin (pI = 7.0) . Furthermore, Vero toxin and Shiga toxin were found to be immunologically unrelated; anti-Vero toxin did not react with Shiga toxin, and similarly anti-Shiga toxin did not react with the Vero toxin in either the Ouchterlony double gel diffusion test or enzyme-linked immunosorbent assay . The Vero toxin purified in this work was found to be immunologically identical to VT2 and Shiga-like toxin II reported previously.

J Infect Dis, 1987 Jun, 155(6), 1249 - 53
Colonic hemorrhage produced in mice by a unique vero cell cytotoxin from an Escherichia coli strain that causes hemorrhagic colitis; Padhye VV et al.; A Vero cell cytotoxin that produces colonic lesions and subsequent colonic hemorrhage in mice has been purified from a strain of Escherichia coli O157:H7 that causes hemorrhagic colitis in humans . This toxin is different in physicochemical properties from the Shiga-like toxin previously associated with this organism and may be responsible for the unique diffuse mucosal hemorrhage in the colon of individuals with E . coli O157:H7 infections.

J Gen Microbiol, 1987 May, 133 ( Pt 5), 1309 - 17
Heterogeneity of Escherichia coli phages encoding Vero cytotoxins: comparison of cloned sequences determining VT1 and VT2 and development of specific gene probes; Willshaw GA et al.; Phages coding for production of Vero cytotoxins VT1 or VT2 in strains of Escherichia coli serotype O157.H7 or O157.H- were morphologically indistinguishable . Their genome size and restriction enzyme digests of the phage DNA were similar . These phages were clearly different in these respects from a VT1-encoding phage isolated from a strain of E . coli O26.H11 (H19) . However the VT1 region cloned from the phage originating in the E . coli O157.H7 strain was identical to the VT1 region previously cloned from the phage carried by H19 . Sequences encoding VT2 that were cloned from the phage in E . coli O157.H- have been mapped and the VT2 region identified by transposon insertion . The cloned regions coding for VT1 or VT2 production had no similarities in the presence of restriction enzyme sites over a distance of about 2 kb, and two VT1-specific probes spanning a region of about 1.4 kb did not hybridize under stringent conditions with cloned VT2 DNA . A 2 kb HincII fragment contained the VT2 genes but hybridized to VT1-encoding phages and recombinant plasmids via flanking phage DNA . A 0.85 kb AvaI-PstI fragment was a specific probe for VT2 sequences and did not hybridize under stringent conditions to phages or plasmid recombinants encoding VT1.

Can J Microbiol, 1987 May, 33(5), 452 - 8
Alterations in lipopolysaccharide produced by chemostat-grown Escherichia coli O157:H7 as a function of growth rate and growth-limiting nutrient; Dodds KL et al.; Escherichia coli O157:H7 was grown in chemostats as continuous cultures at different controlled growth rates and under different nutrient limitations to determine the effects on lipopolysaccharide (LPS) structure . LPS from whole cells and extracted using the hot aqueous phenol method was examined by sodium dodecyl sulfate--polyacrylamide gel electrophoresis (SDS-PAGE) and by gel filtration after hydrolysis with acetic acid . At low growth rates under glucose limitation (D = 0.1 h-1, doubling time (td), approx . 416 min; or D = 0.4 h-1, td, approx . 104 min), E . coli O157 produced high molecular weight LPS identical to that previously characterized from cells grown in batch culture . At a high growth rate (D = 0.8 h-1, td, approx . 52 min), the ratio of high molecular weight LPS to low molecular weight LPS produced greatly decreased . A small amount of high molecular weight LPS, containing O-polysaccharide which lacked amino sugars, and which thus was chemically different from that previously characterized, was produced by the cells at high growth rates . The predominant form of LPS from these cells was of slightly higher molecular weight than rough LPS, probably S-R LPS, and it consistently formed aggregates on SDS-PAGE . This form of LPS was also predominant when E . coli O157 was grown under Mg2+ limitation at an intermediate growth rate (D = 0.4 h-1, td, approx . 104 min).

Vet Microbiol, 1987 Apr, 13(4), 291 - 300
Virulence factors in Escherichia coli isolated from piglets with neonatal and post-weaning diarrhea in Japan; Nakazawa M et al.; A total of 567 strains of Escherichia coli were isolated from piglets with neonatal diarrhea (ND) or post-weaning diarrhea (PWD) in Japan . They were investigated for enterotoxigenicity and possession of adhesins and O antigens . There were clear differences between the strains of ND origin and those of PWD origin in the occurrence of enterotoxigenic E . coli (ETEC) strains, type of enterotoxin and frequency of adhesins: ETEC was found in 77 (25.7%) of 300 strains of ND origin and in 137 (51.3%) of 267 strains of PWD origin . ETEC strains producing heat-labile enterotoxin (LT) or heat-stable enterotoxin (STa), alone or in combination were evenly distributed among the strains of PWD origin . In contrast most of the ETEC strains of ND origin produced LT alone . Adhesins appeared in 42 (54.5%) of 77 ETEC strains of ND origin and in 36 (26.3%) of 137 ETEC strains of PWD origin . Adhesins were less common in ETEC strains of PWD origin than in those of ND origin . Some K99-positive ETEC strains of PWD origin produced both LT and STa . There was a similarity in the distribution of O antigens, particularly O149 and O157, between the strains of ND origin and those of PWD origin.

Infect Immun, 1987 Feb, 55(2), 455 - 61
A plasmid of enterohemorrhagic Escherichia coli O157:H7 is required for expression of a new fimbrial antigen and for adhesion to epithelial cells; Karch H et al.; Of 14 strains of Escherichia coli O157:H7 isolated from patients with hemorrhagic colitis or hemolytic uremic syndrome that were examined for fimbriae, the presence of plasmids, and the ability to adhere to intestinal cells, 13 possessed a 60-megadalton plasmid and were fimbriated as assessed by electron microscopy . These strains adhered to Henle 407 intestinal cells but not to HEp-2 cells or erythrocytes . Three strains were cured of the plasmid and thereafter failed to express fimbriae and lost the ability to adhere to intestinal cells . Conversely, E . coli K-12 transformed with the 60-megadalton plasmid from each of the three strains produced fimbriae and was able to adhere to intestinal cells . A single fimbrial subunit of 16 kilodaltons was observed when purified fimbriae from the transformants and from the 60-megadalton plasmid-containing E . coli O157:H7 strains were disaggregated and subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis . Antisera raised against one preparation of the purified fimbriae reacted strongly with 12 of 14 O157:H7 isolates in an agglutination assay and with purified fimbrial preparations from five E . coli O157:H7 strains in an enzyme-linked immunosorbent assay.

Biochem Biophys Res Commun, 1986 Sep 14, 139(2), 424 - 30
Purification and physicochemical properties of a unique Vero cell cytotoxin from Escherichia coli O157:H7; Padhye VV et al.; A unique Vero cell cytotoxin has been purified to homogeneity from a strain of Escherichia coli O157:H7, using ultrafiltration with Pellicon membrane cassettes and chromatography with QAE Sephadex A-50 . SDS-PAGE showed the molecular weight of the toxin to be 64,000 and the absence of subunits . Based on analytical isoelectric focusing, the toxin had pI of 5.2 . This Vero cell toxin was lethal to mice and showed pathological abnormalities of the mouse colonic mucosa when administered intraperitoneally . Vero cell cytotoxicity of this toxin was not neutralizable with rabbit antiserum to Shiga toxin . Based on physicochemical and immunological properties, this toxin is different from the Shiga-like toxin previously found in this organism.

J Pediatr, 1986 Aug, 109(2), 287 - 91
Hemolytic uremic syndrome and diarrhea associated with Escherichia coli O157:H7 in a day care center; Spika JS et al.; Three cases of hemolytic uremic syndrome with bloody diarrhea occurred during an outbreak of diarrheal illness in children aged 4 months to 9 years who attended a day care center . Thirty-six (34%) of 107 had diarrhea (three or more loose or watery stools in 24 hours) lasting greater than or equal to 3 days . Thirty-one (48%) of 64 children younger than 4 years of age but only (12%) of 43 in the older classes became ill (relative risk 4.0, P less than 0.001) . Eleven (31%) of the 36 children with diarrhea had blood in their stools . Sequential movement of illness from class to class was consistent with person-to-person spread . Ten (18%) of 56 family members of ill children but only one of 45 family members of well children younger than 4 years of age developed a diarrheal illness (P less than 0.05) . Escherichia coli O157:H7 was detected in two of eight stool specimens from children who had bloody diarrhea (one with hemolytic uremic syndrome), two of seven with nonbloody diarrhea, and none of nine who remained well . All three stool specimens obtained at less than or equal to 6 days compared with one of nine obtained at greater than 6 days after onset yielded this organism (P less than 0.02) . E . coli O157:H7 can cause hemolytic uremic syndrome and both nonbloody and bloody diarrhea, and can spread within families and through modes other than foodborne transmission.

Am J Clin Pathol, 1986 Jul, 86(1), 108 - 12
Colonic biopsy in verotoxin-induced hemorrhagic colitis and thrombotic thrombocytopenic purpura (TTP); Morrison DM et al.; Sporadic cases and occasional outbreaks of hemorrhagic colitis recently have been associated with the rare Escherichia coli serotype O157:H7, which is now recognized as an important identifiable cause of bloody diarrhea in patients in whom more common gut pathogens cannot be detected . The authors report such a case in a 49-year-old woman who developed thrombotic thrombocytopenic purpura (TTP) and hemorrhagic transverse and descending colitis with a lesion having many of the features of pseudomembranous colitis . While pseudomembrane formation has been described in the hemolytic uremic syndrome (HUS), these features have not, to the authors' knowledge, been described in a patient with hemorrhagic colitis and TTP secondary to a verotoxin-producing serotype of E . coli.

Zentralbl Bakteriol Mikrobiol Hyg {A}, 1986 Jul, 261(4), 417 - 24
Non-haemagglutinating fimbriae of enteropathogenic Escherichia coli (EPEC); Wadstrom T et al.; Two hundred and thirteen Escherichia coli strains originating in 12 countries were included in the study . Of these, 157 were classical enteropathogenic E . coli (EPEC) serotypes, 54 belonged to O138, O139 and O141 serogroups i.e . porcine edema disease strains and two strains were of serogroup O157 associated with haemorrhagic colitis . Surface hydrophobicity was determined by the salt aggregation test (SAT) . Haemagglutination was assayed against erythrocytes of six animal species with strains grown under conditions known to promote expression of haemagglutinins . Sixty three EPEC strains were hydrophobic i.e . SAT value less than or equal to 0.1-1.6, and of these 15 did not haemagglutinate . Fimbriae were abundant on non-haemagglutinating strain 2178/58 (O26) when grown in nutrient broth . Fewer fimbriae per cell were present after growth on nutrient agar . Heat- and protease treatment reduces the surface hydrophobicity of EPEC strains . We propose that EPEC strains may carry a number of different surface proteins which determine binding to intestinal cells in a similar way as hydrophobic non-haemagglutinating fimbriae determine binding to rabbit intestinal brush borders, cf rabbit EPEC strain RDEC 1.

Br Med J (Clin Res Ed), 1986 Jun 7, 292(6534), 1513 - 6
Haemolytic-uraemic syndrome: clinical experience of an outbreak in the West Midlands; Taylor CM et al.; In 1982-3, 35 children from the West Midlands developed the haemolytic-uraemic syndrome . This was a higher incidence than expected and included an epidemic localised to the Wolverhampton area in July 1983 which comprised 11 cases in two weeks . Twenty three children were treated with dialysis, of whom three died . Six patients developed chronic renal failure, four of them from Wolverhampton . Extrarenal manifestations included neurological sequelae in four, two of whom also developed insulin dependent diabetes mellitus and chronic renal failure . Cardiomyopathy occurred in one child, who also had chronic renal failure . The outcome of these 35 patients was not predictable from prognostic criteria derived from previous experience in Britain . This, together with the high prevalence of extrarenal disease and the geographical localisation of the 1983 outbreak, suggested an aetiological agent new to the region . Faeces from 10 patients were examined for verotoxin producing Escherichia coli, and positive strains of serotype O157.H7 were found in three patients during the Wolverhampton outbreak.

Infect Immun, 1986 Mar, 51(3), 953 - 6
Infection of gnotobiotic pigs with an Escherichia coli O157:H7 strain associated with an outbreak of hemorrhagic colitis; Francis DH et al.; Gnotobiotic pigs inoculated with an Escherichia coli O157:H7 strain isolated from a human with hemorrhagic colitis developed anorexia, lethargy, and watery diarrhea . Bacteria diffusely colonized the cecum and colon surfaces and the crypt epithelium . At bacterial attachment sites, microvilli were effaced, and epithelial cells were irregularly shaped, rounded, or detached . Submucosa, lamina propria, and mesentery were markedly edematous and contained many inflammatory cells.

Am J Vet Res, 1986 Feb, 47(2), 213 - 7
Fimbriae and enterotoxins associated with Escherichia coli serogroups isolated from pigs with colibacillosis; Wilson RA et al.; A comprehensive study of 223 Escherichia coli isolates from pigs with colibacillosis included determination of O serogroups, detection of heat-labile enterotoxin, heat-stable enterotoxin (STa and STb), and identification of K88, K99, 987-P, F-41, and type 1 fimbriae . The incidence of the various E coli types among isolates of pigs of different ages was also determined . Escherichia coli bearing K88 fimbriae accounted for 48% of all isolates studied, were most often of serogroup O157, O149, or O8, and usually produced labile toxin alone or in combination with STa or STb . These E coli were commonly isolated from pigs in each age group studied (0 to 5 days, 6 to 10 days, 11 to 24 days, and greater than 24 days) . Escherichia coli bearing 987-P accounted for 30% of the isolates, were most often of serogroup O141 or O20, and usually produced STa . Escherichia coli bearing K99 accounted for 13% of the isolates, usually were of serogroup O101 or O8, and almost always produced STa . Escherichia coli bearing 987-P or K99 were most often isolated from pigs less than 6 days of age . Fimbriae F-41, when identified, were usually on E coli of serotype O101:K99 . Although infrequently found, type 1 fimbriae were on E coli of most of the serogroups identified in this study.

Infect Immun, 1986 Jan, 51(1), 16 - 23
Experimental infection of infant rabbits with verotoxin-producing Escherichia coli; Pai CH et al.; To study the pathogenesis of diarrheal disease due to verotoxin (VT)-producing Escherichia coli, 3-day-old rabbits were inoculated intragastrically with live E . coli O157:H7 (high VT producer), E . coli O113:K75:H21 (low VT producer), or O157:H45 (VT negative) and were examined for clinical symptoms, bacterial colonization, presence of detectable free VT in the intestines, and histological changes . Diarrhea developed consistently with 10(8) bacteria of E . coli O157:H7 but was observed only infrequently with even a higher dose of E . coli O113:K75:H21 . VT-negative strains failed to cause diarrhea under the same experimental conditions . E . coli O157:H7 was recovered from the colon of infected animals in a significantly higher concentration than from the small intestine, and the clinical symptoms correlated with the presence of detectable free VT in the colon . Histological changes were seen mainly in the mid- and distal colon; these changes were characterized by a vast increase in apoptosis in the surface epithelium, increased mitotic activity in the crypts, mucin depletion, and a mild to moderate infiltration of neutrophils in the lamina propria and epithelium . Multiple foci of attached bacteria were seen on the surface epithelium of the gut-associated lymphoid tissue, cecum, and colon . Bacteria were never seen in epithelial cells or the lamina propria . These mucosal abnormalities as well as clinical symptoms were reproduced in infant rabbits by the intragastric administration of VT alone . These results are consistent with the hypothesis that VT plays a major role in the pathogenesis of diarrhea caused by E . coli O157:H7 and other VT-producing E . coli.

Ann Intern Med, 1984 Nov, 101(5), 624 - 6
Sporadic cases of hemorrhagic colitis associated with Escherichia coli O157:H7; Remis RS et al.; After two outbreaks of hemorrhagic colitis associated with a previously unrecognized pathogen, Escherichia coli O157:H7, a surveillance system was established to identify and study sporadic cases of this distinct clinical illness in the United States . Between August 1982 and April 1984, we identified 28 persons from 11 states who met our case definition and whose stool specimens yielded E . coli O157:H7 . Patients ranged in age from 1 to 80 years . Seventeen patients required hospitalization . All patients recovered, although one developed hemolytic-uremic syndrome 7 days after the onset of bloody diarrhea . Detection of E . coli O157:H7 in stools from persons with hemorrhagic colitis was highly associated with collection of stool specimens within the first 6 days after onset of illness . All E . coli O157:H7 isolates produced a Vero cytotoxin . Hemorrhagic colitis caused by E . coli O157:H7 is widely distributed in the United States as a sporadic illness; clinicians should be aware of its distinctive clinical presentation, and should collect specimens promptly when the diagnosis is suspected.

J Clin Microbiol, 1983 Sep, 18(3), 512 - 20
Laboratory investigation of hemorrhagic colitis outbreaks associated with a rare Escherichia coli serotype; Wells JG et al.; Two outbreaks of hemorrhagic colitis, a newly recognized syndrome characterized by bloody diarrhea, severe abdominal pain, and little or no fever, occurred in 1982 . No previously recognized pathogens were recovered from stool specimens from persons in either outbreak . However, a rare E . coli serotype, O157:H7, was isolated from 9 of 20 cases and from no controls . It was also recovered from a meat patty from the implicated lot eaten by persons in one outbreak . No recovery of this organism was made from stools collected 7 or more days after onset of illness; whereas 9 of 12 culture-positive stools had been collected within 4 days of onset of illness . The isolate was not invasive or toxigenic by standard tests, and all strains has a unique biotype . Plasmid profile analysis indicates that all outbreak-associated E . coli O157:H7 isolates are closely related . These results suggest that E . coli O157:H7 was the causative agent of illness in the two outbreaks.

N Engl J Med, 1983 Mar 24, 308(12), 681 - 5
Hemorrhagic colitis associated with a rare Escherichia coli serotype; Riley LW et al.; We investigated two outbreaks of an unusual gastrointestinal illness that affected at least 47 people in Oregon and Michigan in February through March and May through June 1982 . The illness was characterized by severe crampy abdominal pain, initially watery diarrhea followed by grossly bloody diarrhea, and little or no fever . It was associated with eating at restaurants belonging to the same fast-food restaurant chain in Oregon (P less than 0.005) and Michigan (P = 0.0005) and with eating any of three sandwiches containing three ingredients in common (beef patty, rehydrated onions, and pickles) . Stool cultures did not yield previously recognized pathogens . However, a rare Escherichia coli serotype, O157:H7, that was not invasive or toxigenic by standard tests was isolated from 9 of 12 stools collected within four days of onset of illness in both outbreaks combined, and from a beef patty from a suspected lot of meat in Michigan . The only known previous isolation of this serotype was from a sporadic case of hemorrhagic colitis in 1975 . This report describes a clinically distinctive gastrointestinal illness associated with E . coli O157:H7, apparently transmitted by undercooked meat.

J Hyg (Lond), 1983 Feb, 90(1), 99 - 106
Studies on enterotoxigenic Escherichia coli isolated from persons without diarrhoea in Western Australia; Berry RJ et al.; The epidemiology of enterotoxigenic Escherichia coli (ETEC) was studied in children without diarrhoea in two remote Aboriginal communities in tropical north-western Australia . Serial surveys of the same individuals during different seasons showed that isolations were much more frequent in the wet monsoonal summer than in the dry winter . All E . coli were isolated from symptomless children aged 5 years or less; in addition, clearance of ETEC carriage without treatment was observed in all individuals within 3 months of isolation . Of the 58 ETEC strains isolated, 40 had either an H32 or an O126 antigen . Five O antigens which have never been associated with ETEC (O2, O41, O71, O77 and O157) were found . A recently proposed system to detect ETEC, using groups of polyvalent antisera, would have detected only 3 out of these 58 ETEC strains.

Comp Immunol Microbiol Infect Dis, 1982, 5(4), 405 - 12
Serotypes of Escherichia coli strains isolated from piglets with diarrhea in swine industrial farms; Ciosek D et al.; Serotypes of E . coli strains isolated from piglets, which died with symptoms of diarrhea in 9 swine industrial farms, were determined . Large numbers of serotypes (from 16 to 27) in individual farms were detected . The sets of serotypes from 9 investigated farms differed among each other significantly, depending on the farm and time of examination . It was found that more than one serotype of E . coli may exist in the pig body and contribute to the development of disease . The predominant serotypes, i.e . those comprising more than 10% of serologically determined strains, were found to exist in 6 of the investigated farms and not in the remaining ones . Among the predominant serotypes, particularly important seem to be strains with K88 antigen . For prophylaxis of piglet colibacteriosis in industrial farms in Poland two vaccines for sows are recommended: one containing the K88 antigen only and the other the following serotypes: 0149:K91,K88; 020:K57; 020:K83; O157:K88; 01:K1; 0136:K78; 024:K?; 078:K80 and 0118:K? Strains belonging to these serotypes were the most prevalent in our strain collection.

Infect Immun, 1977 Feb, 15(2), 549 - 55
Serological identification of pig enterotoxigenic Escherichia coli strains not belonging to the classical serotypes; Guinee PA et al.; Escherichia coli strains isolated from pigs suspected to have succumbed to E . coli enterotoxicosis and not belonging to the commonly incriminated (classical) serotypes (O8:K87:K88, O45:K88, O138:K81:K88, O141:K85:K88, O147:K89:K88, O149:K91;K88, and O157:K88) were tested for enterotoxigenicity in the ligated gut test (LGT) using pig intestine . Of 202 strains tested, 54 strains belonging to 13 different O groups were positive in the LGT . Four of these strains had K88 antigen and one possessed K99 antigen . The majority of the strains was not agglutinated by any of the standard OK antisera . Four new K antigens ("K200", "K442", "K2346" and "K2347") were provisionally designated . K200 was found in pig enterotoxigenic strains belonging to O group 8 and carrying flagellar antigen H31 and in non-enterotoxigenic non-motile strains of O group 8, as well as in O group 20 strains isolated from calves succumbing to E . coli septicemia in two countries . The provisional antigen K2346 was encountered in 18 enterotoxigenic strains with various O antigens from two countries . It is proposed to include these two K antigens into the international E . coli antigens scheme . Attempts to demonstrate a common antigen in the nonclassical enterotoxigenic strains lacking K88 and K99 antigens failed.

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