R. J. Gross

An adhesive factor found in strains ofEscherichia coli belonging to the traditional infantile enteropathogenic serotypes

Escherichia coli strains isolated from outbreaks of diarrheal disease were tested for the presence of adhesive factors. Fifty-one of these strains belonged to traditional infantile entero-pathogenic serotypes (EPEC) and 17 belonged to other serotypes. None of these strains were enterotoxigenic and none possessed colonization factors CFA/I or CFA/II, which have been described among strains of enterotoxigenicE. coli (ETEC). EnterotoxigenicE. coli strains from patients with diarrhea and strains which were neither EPEC nor ETEC from subjects without diarrhea were also examined. By means of a tissue culture technique using HEp-2 cells, a new adhesive factor was found to occur with greater frequency in EPEC strains. The adhesive factor was found less frequently in the other groups ofE. coli studied. It was distinct from type 1 pili and was not inhibited by the presence ofD-mannose.

Vero cytotoxin-producing strains of Escherichia coli from children with haemolytic uraemic syndrome and their detection by specific DNA probes

Faecal specimens from 66 children with haemolytic uraemic syndrome in the United Kingdom were examined for strains of Escherichia coli producing Vero cytotoxin (VT). Initially, conventional bacteriological methods were used to identify colonies of E. coli which were then tested for VT production. Subsequently, specific DNA probes for VT1 and VT2 were used in hybridisation tests to detect VT-producing E. coli (VTEC). VTEC strains were isolated from 19 cases and in 15 they belonged to serogroup O157. Fourteen of these O157 strains possessed the flagellar antigen H7 and one was non-motile. The VTEC strains from the remaining four cases belonged to serotypes O26:H11, O104:H2, O153:H25, and O163:H19 together with a rough VT+ strain with flagellar antigen H51. The O157 strains hybridised with either the VT2 probe or both VT1 and VT2 probes. The other VTEC strains hybridised with either the VT1 or VT2 probe. Confirmation of the production of VT1 and VT2 in vivo was obtained by the neutralisation of faecal VT with specific antisera raised against these two cytotoxins.

First recognized community outbreak of haemorrhagic colitis due to verotoxin-producing Escherichia coli O 157.H7 in the UK

The first recognized outbreak of haemorrhagic colitis due to Escherichia coli O 157.H7 in the United Kingdom affected at least 24 persons living in East Anglia over a 2-week period. The illnesses were characterized by severe abdominal pain and bloody diarrhoea of short duration. Eleven patients were admitted to hospital and there was one death. Patients were mainly adult women who had not eaten out of the home in the 2 weeks before onset. Unlike previously reported outbreaks hamburgers were not the vehicle of infection, and a case-control study suggested that handling vegetables, and particularly potatoes, was the important risk factor.

HAEMORRHAGIC COLITIS AND VERO-CYTOTOXIN-PRODUCING ESCHERICHIA COLI IN ENGLAND AND WALES

Vero-cytotoxin-producing strains of Escherichia coli (VTEC) were identified by the use of DNA probes in 39% of faecal samples from patients with haemorrhagic colitis in England and Wales. The patients with VTEC were distributed widely and their ages ranged from 2.5 to 86 years (mean 41). 3 patients died, including a child of 2.5 years. 30 of the 32 VTEC strains belonged to serogroup O157. Plating on sorbitol agar for non-fermenters followed by agglutination with a specific O157 antiserum was a useful screening method for O157 VT+ strains. However, it was not as sensitive as the DNA probe technique and did not detect VTEC of other serogroups.

Escherichia coli diarrhoea.

In recent years it has become clear that three types of Escherichia coli-enterotoxigenic, enteropathogenic, and enteroinvasive-play important roles in the etiology of acute diarrhoea. This report reviews the available knowledge on the epidemiology, clinical features, and pathophysiology of acute diarrhoea caused by these three types of E. coli, summarizes information on their laboratory diagnosis, and outlines priorities for further research. Particular attention is paid to important aspects of the relationship between enterotoxigenic E. coli diarrhoea in young animals and in man, and to recent advances in the development of E. coli vaccines for use in animals and their potential relevance to the development of an E. coli vaccine for use in man.

ENTEROTOXIN TESTING OF ESCHERICHIA COLI CAUSING EPIDEMIC INFANTILE ENTERITIS IN THE U.K.

Three test systems were used to study enterotoxin production by epidemic strains of Escherichia coli from cases of infantile enteritis in well-documented outbreaks in the U.K. The tests used were the Y1-mouse-adrenal-cell test and the Chinese-hamster-ovary-cell (C.H.O.) test for the detection of heat-labile enterotoxin and the infant-mouse test for the detection of heat-stable enterotoxin. All 6 outbreaks had been studied using full serotyping techniques and the results had been published. In each outbreak the epidemiological studies clearly implicated a particular serotype of E. Coli as the epidemic strain and cultures of that serotype were tested for enterotoxin production. Although a control strain validated by other workers was positive in all three systems, the epidemic strains from infantile enteritis were negative. It seems that the three enterotoxin tests used in this study are of little value in recognising strains of E. coli causing epidemics of infantile enteritis in the U.K.

A christening party outbreak of haemorrhagic colitis and haemolytic uraemic syndrome associated with Escherichia coli O 157.H7.

A point source outbreak of haemorrhagic colitis due to Escherichia coli O 157.H7 producing verocytotoxin (VT), took place following a christening party in Birmingham in June 1987. Twenty-six people were affected, six were admitted to hospital and one developed haemolytic uraemic syndrome: there were no deaths. VT + E. coli O 157.H7 was isolated from 13 (57%) of 23 faecal specimens from affected people and from 3 (9%) of 33 specimens from asymptomatic people. Free VT was detected in the faeces of one further asymptomatic person. Illness was associated with eating turkey-roll sandwiches (P less than 0.001) suggesting that cold meats might be an important source of infection.

Phage-typing of Vero-cytotoxin (VT) producing Escherichia coli O157 isolated in the United Kingdom

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.

The serological relationship between Yersinia enterocolitica O9 and Escherichia coli O157 using sera from patients with yersiniosis and haemolytic uraemic syndrome

Sera from patients with yersiniosis, shown to contain antibodies to Yersinia enterocolitica O9; and sera from patients with haemolytic uraemic syndrome (HUS) caused by Escherichia coli O157, were used to investigate serological cross-reactions between Y. enterocolitica O9 and E. coli O157. Lipopolysaccharide (LPS) was isolated from strains of Y. enterocolitica O9 and E. coli O157 and reacted with sera by immunoblotting and ELISA. Sera from patients with HUS contained antibodies to the LPS of E. coli O157 only; 80% of sera from patients with yersiniosis contained antibodies to the LPS of Y. enterocolitica O9 and E. coli O157. This one-way cross-reaction was also detected using hyperimmune rabbit antisera.

Adhesion to cells in culture and plasmid profiles of enteropathogenic Escherichia coli isolated from outbreaks and sporadic cases of infant diarrhoea

Enteropathogenic strains of Escherichia coli (EPEC) that caused 10 outbreaks of infant diarrhoea in the U.K. between 1968 and 1986 were studied. All gave localised adherence (LA) to HEp-2 cells, HeLa cells and Intestine 407 cells in culture. All hybridised with the EPEC adherence factor (EAF) probe. The hybridising sequences were carried on plasmids ranging in size from 26 to 76 MDa. EPEC from sporadic cases of infant diarrhoea occurring between 1979 and 1986 that belonged to the same serotypes as the outbreak strains were also studied. All strains of serotypes O111ab.H2, O114.H2, O119.H6, O127.H6 and O142.H6 gave LA and were EAF-positive. In other serotypes, non-adhering strains or strains giving diffuse adherence were found also. In addition, strains of serotype O128.H2 which gave LA but did not hybridise with the EAF probe were identified. The strains isolated from sporadic cases of diarrhoea in the U.K. were similar, with respect to adhesion and hybridisation, to those isolated from sporadic cases of diarrhoea in developing countries.