Fibronectin binding and cell-surface hydrophobicity of attaching effacing enteropathogenic Escherichia coli strains isolated from newborn and weanling rabbits with diarrhoea

Abstract 32 different strains of Escherichia coli isolated from rabbits with diarrhoea were studied for cell-surface properties which may be involved in intestinal colonisation. Strains isolated from diarrhoeic suckling (6 strains) and weaning (26 strains) rabbits which were shown to attach to brush borders in vivo, showed high relative cell-surface hydrophobicity as determined by the Salt Aggregation Test (SAT) when grown on Colonisation Factor Antigen (CFA) agar at 33°C. Cells of these strains grown to express surface hydrophobicity were also defined as high, moderate or low binders of ¹²⁵I-fibronectin or its ¹²⁵I-29-kDa fragment in a standard binding assay. Based on these findings, we propose that binding to intestinal cell surface (mucus)-associated fibronectin may be an early important step in intestinal colonisation of the small bowel in enteropathogenic E. coli (EPEC) diarrhoea in rabbits and other animal species.     

Immune response to Escherichia coli antigens entrapped in liposomes. I. Immunopathological studies

In this study, we have searched for an effective mucosal delivery system for a purified E. coli antigen which elicits anticolonization and anti-toxic immunity. E. coli colonization factor antigen (CFA/I) and heat-labile enterotoxin (LT) were encapsulated in liposomes. To determine the efficacies of soluble and liposome-encapsulated E. coli antigens young rabbits were mucosally treated with three oral doses of E. coli antigens given 7 days apart. Ten days after the last booster, rabbits were orally challenged with 5 x 10(9) bacterial cells (O78:H11 serotype). The experimental results allow of making some remarks which can be correlated with the protection obtained in vaccinated animals: (a) immunization with E. coli antigens entrapped in liposomes ensured protection against ETEC strains; (b) lower protection against homologous and heterologous CFA/I +(LT- ST+) strains were noticed; (c) adhesion of labelled -3H-leucine-bacteria to the intestinal mucosa revealed a maximum distribution in duodenum-jejunum and minimum in the colonic mucosa; (d) it contributed to the release of inoculated virulent bacteria from intestinal tract; (e) humoral, cellular and histopathological findings confirm the afore mentioned observation. Summing up, these results suggest that liposomes are very good carriers for E. coli antigens and these findings highlight the potential use of LT and CFA/I antigens entrapped in liposomes as mucosal and humoral induction of immune response and make them a candidate for future use in prophylaxis of diarrhoea in man.     

Effectiveness of phages in treating experimental Escherichia coli diarrhoea in calves, piglets and lambs

A mixture of two phages, B44/1 and B44/2, protected calves against a potentially lethal oral infection with an O9:K30,99 enteropathogenic strain of Escherichia coli, called B44, when given before, but not after, the onset of diarrhoea; a mixture in which phage B44/3 was replaced by phage B44/3 was effective after the onset of diarrhoea. Calves that responded to phage treatment had much lower numbers of E. coli B44 in their alimentary tract than untreated calves. Usually, high numbers of phage B44/1 and rather lower numbers of phage B44/2 or B44/3 were present in the alimentary tract of these animals. At death, most calves that had not responded to treatment with phages B44/1 and B44/2 had high numbers of mutants of E. coli B44 resistant to phage B44/1 in their small intestine. Phage-treated calves that survived E. coli infection continued to excrete phage in their faeces, at least until the numbers of E. coli B44 also excreted were low. The phages survived longer than E. coli B44 in faecal samples taken from phage-treated calves and exposed to the atmosphere in an unheated animal house. Calves inoculated orally with faecal samples from phage-treated calves that contained sufficient E. coli B44 to cause a lethal infection remained healthy. A mixture of two phages, P433/1 and P433/2, and phage P433/1 alone cured diarrhoea in piglets caused by an O20:K101,987P strain of E. coli called P433. The numbers of the infecting bacteria and phages in the alimentary tract of the piglets resembled those in the calves. Another phage given to lambs 8 h after they were infected with an O8:K85,99 enteropathogenic strain of E. coli, called S13, reduced the numbers of these organisms in the alimentary tract and had an ameliorating effect on the course of the disease. No phage-resistant mutants of E. coli S13 were isolated from the lambs. The only mutants of E. coli B44 and P433 that emerged in the calves and piglets were K30- or K101- and resistant to phage B44/1 or P433/1 respectively; those tested were much less virulent than their parent strains.     

Group A Rotavirus as a Cause of Neonatal Calf Enteritis in Sweden

Faeces samples were collected during outbreaks of neonatal calf diarrhoea in 14 beef and dairy herds. Samples from 33 calves were taken at the onset of diarrhoea as well as from 30 calves with no signs of enteritis. No vaccines or medical treatment had previously been given. The mean age of the calves was 16.8 days (SD 8.2). The clinical evaluation of faeces consistency corresponded well to the dry matter content of the faeces (p<0.001). The samples were analyzed for rotavirus, Cryptosporidium species and Escherichia coli K99+. Group A rotavirus was detected by ELISA and RNA Polyacrylamide gel electrophoresis (RNA-PAGE) in 14/33 (43.8%) of the samples from scouring calves and 1/30 (3.7%) of the samples from non-scouring calves. The correlation between group A rotavirus and diarrhoea was statistically significant (p<0.001). No non-group A rotaviruses were found by RNA-PAGE. Cryptosporidium species were detected through demonstration of oocysts in smears from 12/63 (19.0%) of the faecal samples, but no statistically significant correlation between diarrhoea and detection of oocysts was demonstrated. Escherichia coli K99+ was not detected in any faeces sample. The clear association between group A rotavirus and diarrhoea is suggested to be due to low pathogenic load in the herds.     

Erratum

Abstract Previous studies have identified enteroadherent Escherichia coli that exhibit localized adherence, diffuse adherence and atypical diffuse adherence as diarrhoeagenic agents associated with infantile diarrhoea in Calcutta, India. In this study, a DNA probe specific for enteroaggregatove adherence was used to determine the etiological significance of enteroaggregative E. coli in the causation of diarrhoea. From a total of 330 strains of E. coli recovered from 159 cases of acute secretory diarrhoea and 174 cases of invasive diarrhoea, 20 strains hybridized with the probe, whereas of the 25 E. coli strains recovered from 25 healthy controls only 1 strain hybridized with the probe. Of the 21 probe positive strains, 19 adhered to HeLa cells in the typical stacked-brick pattern while 2 strains recovered from 2 cases of secretory diarrhoea adhered to the glass surface in a hitherto undescribed formation which we have termed, based on the appearance, as the honey-comb pattern. The enteroaggregative E. coli strains identified in this study did not produce any conventional enterotoxins and were significantly associated with patients with secretory diarrhoea (10.7%) than with invasive diarrhoea (1.7%). The results of this study indicate that enteroaggregative E. coli play a causal role in acute secretory diarrhoea in this part of the world which lends credence to the involvement of a potent toxin in the pathogenesis of EAggEC mediated infections.     

Vero cell toxins in Escherichia coli and related bacteria: transfer by phage and conjugation and toxic action in laboratory animals, chickens and pigs

Sixty-eight of 519 strains of Escherichia coli and six of 10 strains of Pseudomonas aeruginosa produced toxins acting on Vero cells (VT+); all of 63 Salmonella, Shigella, Klebsiella, Enterobacter and Proteus strains were VT-. Most of the VT+ E. coli strains were from weaned pigs suffering from oedema disease and/or diarrhoea and belonged to serogroups O141:K85,88, O141:K85, O138:K81, and O139:K82; six VT+ E. coli strains were from diarrhoeic human babies, four of serogroup O26 and two of serogroup O128. The VT genes in two of the O26 strains and in the O128 strains were located in the genome of the phages with which they were lysogenized. One O141:K85,88 pig E. coli strain transferred its VT genes, probably by conjugation, to E. coli K12. The VTs of the human E. coli strains, the pig E. coli strains and the P. aeruginosa strains were antigenically different from each other; unlike the others, the P. aeruginosa VT was heat-resistant. Cell-free preparations of cultures of E. coli K12 to which the VT genes of the four human E. coli strains had been transferred caused fluid accumulation in ligated segments of rabbit intestine. Inoculated intravenously, they were lethal for mice and rabbits; similar preparations of E. coli K12 to which the VT genes of the pig E. coli strain had been transferred produced a disease in pigs that clinically and pathologically resembled oedema disease.     

Oral rehydration formula containing alanine and glucose for treatment of diarrhoea: a controlled trial.

OBJECTIVE--To determine whether adding L-alanine to the glucose based oral rehydration solution recommended by the World Health Organisation would improve its efficacy in treating acute diarrhoea. DESIGN--Randomised double blind controlled trial of oral rehydration solution containing L-alanine and glucose. SETTING--Inpatient service of a hospital treating diarrhoea. PATIENTS--97 Male patients aged 6-59 years admitted to the hospital with acute and severe dehydration due to diarrhoea associated with Vibrio cholerae or enterotoxigenic Escherichia coli. Forty nine received the standard glucose based oral rehydration solution (control group) and 48 this solution with alanine added (study group). INTERVENTIONS--All of the patients received rapid intravenous acetate solution for the initial four hours after admission, which fully corrected the signs of dehydration. They were then admitted to the study and randomised. Immediately after the intravenous treatment oral rehydration treatment was started. All of the patients received oral tetracycline for 48 hours, starting 24 hours after start of the study. If signs of dehydration reappeared during oral treatment patients were given rapid intravenous acetate solution until they were fully corrected and then continued to take the assigned oral rehydration solution. END POINT--Passage of the last watery stool. MEASUREMENTS and MAIN RESULTS--The median stool output/kg body weight during the initial 24 hours of oral rehydration treatment and until diarrhoea stopped was reduced in the study group compared with the control group from 309 ml to 196 ml and from 393 ml to 236 ml respectively. Intake of oral rehydration solution and intravenous acetate solution was reduced from 455 ml to 308 ml and from 616 ml to 425 ml respectively. Two patients in the study group compared with 18 patients in the control group required unscheduled rapid intravenous acetate solution to correct signs of dehydration during oral rehydration treatment. CONCLUSION--Oral rehydration solution containing L-alanine was considerably better than standard oral rehydration solution at reducing the severity of symptoms and the need for fluid of male patients with diarrhoea associated with V cholerae and enterotoxigenic E coli.     

Role of verocytotoxigenic Escherichia coli in cattle and buffalo calf diarrhoea

Abstract 273 Strains of Escherichia coli isolated from diarrhoeic and healthy control cattle and buffalo calves in Sri Lanka, were tested for Verocytotoxin (VT) and for heat-stable (ST) and heat-labile (LT) enterotoxins. VT and ST toxigenic E. coli were significantly associated with diarrhoea, accounting for 28% and 18% of diarrhoeic episodes, respectively. LT toxigenic E. coli were not significantly associated with diarrhoea.     

Our experiences with isolation of heat-labile enterotoxin from Escherichia coli

From the Escherichia coli strain isolated from a patient suffering from diarrhoea a homogenate and concentrated culture filtrate were prepared. From these materials the heat-labile enterotoxin was isolated after its elution with 0.2 M D-galactose from Sepharose 6B column. The obtained enterotoxin was positive in the rabbit ileal loop test up to a concentration of 1 microgram protein/ml. In the immunodiffusion test it reacted in a concentration up to 5 micrograms protein/ml with anticholeragen and in a concentration up to 30 micrograms protein/ml with its specific antiserum. This antiserum was prepared by intramuscular immunization of rabbits by enterotoxin with complete Freund's adjuvant.     

Adhesive Escherichia coli in inflammatory bowel disease and infective diarrhoea.

The clinical features of ulcerative colitis and Crohn''s disease are similar to those of infections of the bowel, although their cause is uncertain. Many bacteria that cause intestinal diseases adhere to the gut mucosa, and adhesion of pathogenic Escherichia coli is resistant to D-mannose. The adhesive properties of isolates of E coli were assessed by assay of adhesion to buccal epithelial cells with mannose added. The isolates were obtained from patients with inflammatory bowel diseases (50 with a relapse of ulcerative colitis, nine with ulcerative colitis in remission, 13 with Crohn''s disease, and 11 with infectious diarrhoea not due to E coli) and 22 controls. The median index of adhesion to buccal epithelial cells (the proportion of cells with more than 50 adherent bacteria) for E coli from patients with ulcerative colitis in relapse was significantly higher (43%) than that for controls (5%) and patients with infectious diarrhoea (14%). The index was not significantly different among isolates from patients with ulcerative colitis in relapse, Crohn''s disease (53%), and ulcerative colitis in remission (30%). If an index of adhesion of greater than 25% is taken as indicating an adhesive strain 86% of isolates of E coli from patients with inflammatory bowel disease were adhesive compared with 27% from patients with infective diarrhoea and none from controls. The adhesive properties of the isolates from patients with inflammatory bowel disease were similar to those of pathogenic intestinal E coli, raising the possibility that they may have a role in the pathogenesis of the condition; the smaller proportion of adhesive isolates in patients with infective diarrhoea due to other bacteria suggests that the organism may be of primary importance rather than arising secondarily.     

The development of a febrile response to pyrogen in the thyroid-deficient rabbit

The development of the febrile response to E. coli lipopolysaccharide (1.5 micrograms/kg, i.v.) in thyroid-deficient rabbits has been studied. Twenty-eight New Zealand White rabbits weighing 2.1-2.3 kg were used. Hypothyroidism was induced by treatment with propylthiouracil (100 or 200 mg/kg body wt./15 days). Thyroid-deficient animals showed a reduction in the febrile response to lipopolysaccharide, but the effect was significantly different (p less than 0.01) from the control only for rabbits treated with 200 mg/kg of propylthiouracil. Propranolol (2 mg/kg, i.p.) given 30 min before lipopolysaccharide also reduced (p less than 0.01) the fever response in control rabbits. The results of this experiment are consistent with the hypothesis that the reduction in the febrile response of thyroid-deficient rabbits is due to the reduced number of beta-adrenergic receptors, or to a change in the availability of neurotransmitter in thermogenically active tissues, such as brown fat.     

Isolation and characterization of Shiga toxin-producing Escherichia coli (STEC) and enteropathogenic Escherichia coli (EPEC) from calves and lambs with diarrhoea in India

AIMS: To determine the prevalence and molecular characteristics of Shiga toxin-producing Escherichia coli (STEC) and enteropathogenic E. coli (EPEC) in calves and lambs with diarrhoea in India. METHODS AND RESULTS: Faecal samples originating from 391 calves and 101 lambs which had diarrhoea were screened for presence of E. coli. A total number of 309 (249 bovine and 60 ovine) E. coli strains were isolated. A total of 113 bovine and 15 ovine strains were subjected to multiplex polymerase chain reaction (m-PCR) for detection of stx1, stx2, eaeA and EHEC hlyA genes. STEC and EPEC belonging to different serogpoups were detected in 9.73% of calves studied. Six per cent and 26.66% of lambs studied were carrying STEC and EPEC, respectively. Majority of the STEC serogroups isolated in this study did not belong to those which have been identified earlier to be associated mainly with diarrhoea and enteritis in cattle and sheep outside India. The most frequent serogroup among bovine and ovine EPEC was O26 (40%). One of the most important STEC serogroup O157, known for certain life-threatening infections in humans, was isolated from both bovine and ovine faecal samples. CONCLUSIONS: A high percentage of STEC and EPEC belonging to different serogroups are prevalent in calves and lambs with diarrhoea in India and could be the cause of disease in them. SIGNIFICANCE AND IMPACT OF THE STUDY: The study reports, for the first time, the isolation and characterization of STEC and EPEC serogroups associated with diarrhoea in calves and lambs in India. Many STEC and EPEC strains belonged to serogoups known for certain life-threatening diseases in humans.     

Effect of fermented soya beans on diarrhoea and feed efficiency in weaned piglets

AIMS: To evaluate anti-diarrhoeal and growth enhancing properties of fermented soya beans in weaned piglets. METHODS AND RESULTS: In a first phase piglet diet, toasted full-fat soya beans (20%) were replaced with either cooked soya beans or Rhizopus microsporus or Bacillus subtilis fermented soya beans. The effect on the incidence, severity and duration of diarrhoea in enterotoxigenic Escherichia coli (ETEC)-challenged weaned piglets was determined (pen trial, 24 piglets per treatment). Severity of diarrhoea was significantly less on the diet with Rhizopus-fermented soya beans compared with the control diet containing toasted soya beans. Piglets fed fermented soya beans showed increased feed intake (13 and 12%), average daily weight gain (18 and 21%) and feed efficiency (3 and 8%) (for Rhizopus and Bacillus-fermented soya beans, respectively). However, in the treatment groups an unequal mortality and a potential unequal distribution of receptor-positive piglets were observed. CONCLUSIONS: Cooked and fermented soya beans could be beneficial in the control of diarrhoea in ETEC-challenged weaned piglets (particularly Rhizopus fermented) and significantly improved weight gain and feed intake (particularly Bacillus fermented). SIGNIFICANCE AND IMPACT OF THE STUDY: Fermented soya beans could offer benefits with respect to the control of diarrhoea and feed efficiency in piglets.     

occurrence of mannose- resistant adhesins MRHA in E.Coli strains isolated from children with diarrhea]

The study was aimed at determination of the frequency of occurrence of mannose-resistant adhesins in E. coli strains isolated from children with diarrhoea. It was also of interest whether their presence is associated with the serological type or other virulence factors. The material used in this study consisted of 1022 strains of E. coli (EPEC, ETEC and EIEC) and 3431 isolates from sick children and 960 from healthy children (non-EPEC-ETEC-EIEC). Enterotoxigenicity and entero-invasiveness of strains was evaluated by biological tests performed on animals and in tissue culture. Production of MRHA adhesins was determined by the test of mannose-resistant active hemagglutination, and of colonization factors antigens CFA by application of agglutination and agar gel immunodiffusion tests. Most frequently MRHA adhesins were produced by ETEC strains-80% of strains. All of them appeared to be a colonization factor antigen CFA/I. EPEC strains produced various MRHA adhesins only by 12.6% of strains. Production of MRHA adhesins by EIEC strains was not detected. Frequency of occurrence of MRHA adhesins in E. coli strains which were non-EPEC-ETEC-EIEC was dependent from the isolation source. MRHA adhesins were most frequently found in strains isolated from sporadic cases of light diarrhoea in ambulatory treated children (49%), much less among isolates from children hospitalized because of severe diarrhoea (33%), and from healthy children in 9% of isolates only. These results may indicate the potential role of MRHA adhesins in pathogenesis of diarrhoea in children.     

A recombinant Escherichia coli heat-stable enterotoxin b (STb) fusion protein eliciting neutralizing antibodies

Abstract STb is a heat-stable enterotoxin elaborated by enterotoxigenic Escherichia coli strains associated with weaning piglets and is responsible for diarrhoea in those animals. The maltose binding protein (MBP) of E. coli was used as a carrier for STb, a poorly immunogenic molecule. Constructions were produced where the gene coding for mature STb toxin (MBP-STb) and a fragment of the gene spanning the major epitopic region of STb (AA8–AA30)(MBP-STb₂) were fused to malE gene coding for MBP. The fusion proteins accumulated in the periplasm and were detected with a polyclonal antibody raised against the purified toxin. MBP-STb induced secretion in the biological model whereas MBP-STb₂ was non-toxic. Immunization of rabbits evoked an antibody response to STb for these two fusion proteins. However, only MBP-STb elicited antibodies that effectively neutralized the toxicity of pure STb toxin as determined in the rat loop assay.     

Inhibition of biological activities of the aerobactin receptor protein in rough strains of Escherichia coli by polyclonal antiserum raised against native protein

The aerobactin iron-uptake system of plasmid ColV-K30, genetically isolated from other plasmid determinants by molecular cloning, was sufficient to restore full virulence in a mouse peritonitis model to a clinical Escherichia coli isolate, D551 (O78:H-), whose resident aerobactin-encoding ColV plasmid had been lost by curing. Antiserum was raised in rabbits against live E. coli K12 cells expressing the outer-membrane aerobactin receptor protein and absorbed with an isogenic strain lacking the receptor. This antiserum inhibited binding of aerobactin, cloacin DF13 and bacteriophage B74K to the native protein in whole E. coli K12 bacteria expressing the receptor, or in membranes prepared from such organisms. However, it did not react with the native receptor protein in several wild strains unless lipopolysaccharide was first removed by treatment with trichloroacetic acid, nor did it protect mice in experimental infections with strain D551. Antisera raised in rabbits against partially or fully denatured forms of the aerobactin receptor reacted only in assays involving denatured protein; they showed no inhibition of the biological activities of the native receptor.     

Surveillance of patients attending a diarrhoeal disease hospital in Bangladesh

In October 1979 a surveillance system was set up at the International Centre for Diarrhoeal Disease Research, Bangladesh, Hospital at Dacca to study a 4% systematic sample of the 100 000 patients with diarrhoea who come to the hospital for care each year. From December 1979 to November 1980 inclusive, 3550 patients were studied. A recognised pathogenic organism was identified for 66% of patients screened for all pathogens, one-third of whom had a mixed infection with two or more agents. Enterotoxigenic Escherichia coli was the most common enteropathogen detected in all age groups (detection rate 20%), followed by rotavirus (19%), Campylobacter jejuni (14%), and Shigella (12%). Infants and young children (up to 5 years) were most often infected with rotavirus, enterotoxigenic E coli, and C jejuni and older children (5-14 years) had more infections with enterotoxigenic E coli, Shigella, and E histolytica. Surveillance has helped to define the range of disease among patients attending the Dacca Hospital. Sixty-five per cent of patients complained of watery diarrhoea, a presentation that was significantly more common in patients with Vibrio cholerae 0:1 (91%), enterotoxigenic E coli (78%), rotavirus (77%), and C jejuni (71%) than in all patients studied. Dysentery, defined as a history of diarrhoea with blood, was the presenting complaint of 20% of all patients but 55% of those with Shigella. Only patients with V cholerae 0:1 and enterotoxigenic E coli were at increased risk for severe dehydration. In addition surveillance has been used to identify areas where patient care can be improved and to generate new ideas for research.     

Acid-Base and Electrolyte Changes in 1–3 Days Old Piglets Infected with Enteropathogenic Escherichia Coli and in Spontaneous Cases of Piglet Diarrhoea

Infection perorally with enteropathogenic E. coli (ST +LT) bacteria in 57 newborn piglets gave rise to watery diarrhoea in 50 (88%) piglets and was lethal in 17 (34 %) cases. The diarrhoea was associated with a progressing partially compensated metabolic acidosis indicated by significantly decreased pH, pCO2 and RE values. The acidosis (BE-values) was significantly correlated with increased blood LA and serum K+ values. The dehydration during the disease was confirmed by increased Hb, Hct, serum protein and urea values as well as loss of weight. The changes were most pronounced in piglets that died and a BE value of —10 mmol/1 seemed to be a critical limit at which the prognosis could be considered poor. The changes in acid-base status and water balance was confirmed in 64 piglets with spontaneous cases of E. coli diarrhoea.     

Fatal ulcerative colitis in a western lowland gorilla (Gorilla gorilla gorilla)

A captive western lowland gorilla (Gorilla gorilla gorilla) presented with watery diarrhoea that progressed to become profuse and haemorrhagic. Faecal analyses revealed Balantidium (B.) coli trophozoites and salmonella-like bacteria. Despite treatment the gorilla died on the 5th day after onset of symptoms. Post-mortem examination revealed a severe erosive-ulcerative superficial and deep colitis. Histological examination of post-mortem samples of the colon showed plentiful B. coli invading into the mucosa and submucosa, whilst PCR screening of bacterial DNA could not confirm any bacteria species which could be connected to the clinical picture. As B. coli is usually a non-pathogenic gut commensal, and as this animal previously showed evidence of non-symptomatic infection of B. coli, it is possible that the switch in pathogenicity was triggered by an acute bacterial infection. Despite successful treatment of the bacterial infection the secondary deep invasion of B. coli was not reversed, possibly because of the failure of the treatment regimen, and led to the death of the gorilla.     

Value of stool examination in patients with diarrhoea.

Findings of stool examinations in 1593 patients with diarrhoea due to a single enteric pathogen--enterotoxigenic Escherichia coli rotavirus, Shigella, Campylobacter jejuni, Vibrio cholerae 0:1, Entamoeba histolytica, or Giardia lamblia--were reviewed to determine how well they predicted the agent associated with the diarrhoea. Specimens were examined visually for blood and mucus, tested for pH, and examined under a microscope for the presence of red and white blood cells, parasites, and stool fat. Although visible blood was more common in specimens from patients infected with Shigella (51%) and Ent histolytica (39%) than in those from patients infected with other agents (6%; p less than 0.01), patients infected with Shigella were most likely to have numerous faecal leucocytes (greater than 50/high power field: 39% v 8% of all patients and 7% of patients infected with Ent histolytica, p less than 0.01 in both cases). Patients infected with enterotoxigenic E coli, rotavirus, V cholerae 0:1, or C jejuni had loose stools with fewer red or white cells. Patients infected with rotavirus and C jejuni were more likely to have acid stools with 3 to 4+ fat, but these findings were related to young age and breast feeding. Stool examination is most useful in establishing a diagnosis of dysentery and in helping to distinguish between patients infected with Shigella and Ent histolytica; it is of limited usefulness in discriminating between pathogens causing watery diarrhoea.