Prospective study of verocytotoxin-producing, enteroaggregative and diffusely adherent Escherichia coli in different diarrhoeal states.

One hundred and eighty-one stool specimens from patients with various types of diarrhoea (135 patients) or from non-diarrhoeal controls (23 acute medical patients, 23 inflammatory bowel disease in remission) were investigated using a colony-blot DNA hybridization assay for the presence of Verocytotoxin-producing (VTEC), enteroaggregative (EAggEC) and diffusely adherent (DAEC) Escherichia coli. Twelve patients had probe-positive EAggEC in the stool and 8 of these had diarrhoea, 6 following recent travel. Eight patients had DAEC, 7 of whom had travellers'' diarrhoea. Six of 10 (60%) travellers with gastroenteritis, but without a recognized enteric pathogen, were positive for EAggEC (4) or DAEC (2). Five of 10 (50%) travellers with gastroenteritis related to a recognized enteric pathogen also had DAEC identified in their stool. Of the 23 acute medical control patients 11 had been abroad, 4 of these were immigrants and had EAggEC. VTEC were not found and, with one exception, immunoassays for antibodies to E. coli O 157 and O 2 lipopolysaccharides were negative.     

Enterotoxigenic enteric bacteria in foods and outbreaks of food-borne diseases in Sweden.

All of 86 food routinely examined for potentially pathogenic enteric bacteria were found to harbour one or more coliform species. None of the strains isolated produced heat-labile enterotoxin (LT) or showed invasive properties. The suckling mouse test indicated that one strain of Escherichia coli produced heat-stable enterotoxin (ST). Twelve incidents of suspected food poisoning were also investigated. In two of them the foods examined contained LT-producing strains of E. coli and in two there were LT-producing strains of Klebsiella pneumoniae. The counts of viable enterotoxigenic micro-organisms in these foods were 3000-30,000 E. coli/g and 50,000 to 1 million K. pneumoniae/g. The dominant symptom in all the incidents was watery diarrhoea. These seem to be the first reported cases of foodborne enterotoxigenic enteric bacteria in Europe. Though enterotoxigenic E. coli and related gram-negative enterotoxin-producing species are rare in correctly handled food in Sweden, these micro-organisms should be searched for when outbreaks of food poisoning are investigated.     

Infection with bacterial enteropathogens in Swedish travellers to South-East Asia--a prospective study

Infection with potential bacterial enteropathogens was studied prospectively in 94 Swedish travellers. Three faecal samples were collected, regardless of diarrhoeal symptoms, after each of three 1-week stays in Singapore, Hong Kong and Japan. The specimens were analyzed for salmonella, shigella, yersinia, campylobacter and different enterotoxin-producing bacteria. A potential enteropathogen was identified in 30% (28/94) of the participants, i.e. in 26% of the healthy and in 39% of the travellers with diarrhoea. The most common isolates were enterotoxigenic bacteria of different species (14%), salmonella (11%) and campylobacter (7%). By performing enterotoxin-tests on six different colonies from the primary culture of each specimen enterotoxigenic Escherichia coli (ETEC) as well as enterotoxin-producing Klebsiella sp., Citrobacter sp. and Morganella morganii were identified. The latter strains were as prevalent as ETEC. In the 33 participants with diarrhoea enterotoxigenic bacteria (18%) and campylobacter (18%) were the most common isolates. Campylobacter-infected travellers developed symptomatic disease (6/7) significantly (P less than 0.02) more often than those infected with salmonella (3/10) or enterotoxigenic bacteria (6/13; 2 ETEC, 4 other species).     

Acute diarrhoeal diseases in infants aged below six months in hospital in Calcutta, India: an aetiological study.

In a prospective 2-year study, 218 infants aged less than 6 months admitted to a children's hospital in Calcutta with acute diarrhoea and 102 infants (control group) from the out-patient department of the same hospital with similar age, sex and socio-economic composition as the diarrhoea patients, were concurrently investigated for enteropathogenic agents in the faeces. Enteropathogenic Escherichia coli, enterotoxigenic E. coli, and enteroadherent E. coli constituted the 3 types of diarrhoeagenic E. coli most frequently (57.4%) detected in the faeces of diarrhoeic infants either as a sole pathogen or in association with other microorganisms. Other enteropathogens detected were rotavirus, Campylobacter jejuni, Salmonella typhimurium and Aeromonas hydrophila. The frequency of detection of various aetiological agents was 72%; in the remaining 28% an infectious aetiology could not be determined. The study suggests that diarrhoeagenic E. coli plays a major role in the causation of acute diarrhoea in infants aged under 6 months in Calcutta.     

Diarrhoeal disease in children less than one year of age at a children's hospital in Guangzhou, People's Republic of China.

We performed a case-control study of diarrhoea to determine its causes in children less than 1 year old in Guangzhou, People's Republic of China, in April to September 1989. Stools were cultured for Salmonella, Shigella, Campylobacter and vibrios by standard techniques; rotavirus (RV) was identified by polyacrylamide gel electrophoresis; and specific deoxyribonucleic acid probes were used to identify Escherichia coli containing genes coding for Shiga-like toxin I and II, enteropathogenic E. coli adherence factor, and enteroinvasive E. coli (EIEC). E. coli isolates were tested for heat-labile toxin (LT) and heat-stable toxin (ST) production and mannose-resistant adherence to HeLa cells. Rotavirus was identified in 13 of 174 children with diarrhoea (cases) and in 2% of 174 age-matched children without diarrhoea (controls), P less than 0.001. C. jejuni was identified in 10% of cases and 2% of controls, P = 0.003. Giardia lamblia was identified in 4 cases, LT and ST enterotoxigenic E. coli (ETEC) in 2, and S. flexneri in 1 case; they were not found in controls. ETEC that produced LT only was isolated from 5 cases and 3 controls, P = 0.721; E. coli that adhered to HeLa cells in a diffuse pattern was isolated from 30 cases and 40 controls, P = 0.229; and E. coli that adhered in an aggregative pattern was isolated from 20 cases and 18 controls, P = 0.863. EIEC was not isolated from cases or controls. Nine cases (5%) developed persistent diarrhoea (greater than 14 d duration). C. jejuni and aggregative E. coli were isolated from different children with persistent diarrhoea.(ABSTRACT TRUNCATED AT 250 WORDS)     

Diarrhoeagenic bacterial pathogens in HIV-positive patients with diarrhoea in rural communities of Limpopo Province,South Africa

Potential enteric bacterial pathogens in 60 HIV-positive patients with chronic diarrhoea in rural communities of the Limpopo Province, South Africa, were identified using standard microbiological methods. The Kirby-Bauer disk-diffusion method was employed to determine antibiograms of isolated bacteria. Results revealed that diarrhoeagenic bacterial agents were isolated from 48 (80%) of the 60 HIV-positive patients with diarrhoea. Forty-four (73.3%) and 16 (26.7%) of the 60 patients were female and male respectively in the age range of 17-55 years with a mean of 34 years. Bacterial pathogens isolated comprised Campylobacter species (20.0%), Plesiomonas shigelloides (16.6%), Aeromonas species (13.3%), and Escherichia coli, Shigella and Salmonella species (10.0% each). No attempts were made to isolate parasites, fungi, or viruses. Antibiotic susceptibility profiles revealed resistance of the isolates to ampicillin, cephalothin, chloramphenicol, erythromycin, and streptomycin. However, all (100%) of P. shigelloides and Salmonella species were sensitive to nalidixic acid and ciprofloxacin. Most isolates were susceptible to nalidixic acid, ciprofloxacin, and gentamicin, indicating the usefulness of these drugs, although antibiograms may not always correlate with clinical usefulness.     

Detection of diarrhea-causing Escherichia coli using DNA-probes]

To assess the role of enterovirulent Escherichia coli at home and abroad, faeces samples of patients with diarrhoea and of healthy controls in Tunisia, Seville (southern Spain) and the Netherlands were investigated. Enterovirulent E. coli were identified by hybridization with five different non-radioactively labelled DNA probes specific for enterotoxigenic E. coli (ETEC), enteropathogenic E. coli (EPEC) and verocytotoxin producing E. coli (VTEC). ETEC was the main causative agent of travellers' diarrhoea in Tunisia. The isolation of ETEC in the Netherlands was shown to be related to travel in endemic areas. EPEC probe positive strains were isolated in children and in adults, but were not in all cases associated with intestinal disease. During this study no VTEC were detected. From an immunocompromised kidney transplantation patient with sepsis and diarrhoea ETEC were isolated from blood.     

烟台市食品行业从业人员肠道致病菌的检测及意义

目的:对烟台市从事食品行业人员的肠道致病菌进行检测,为当地食品安全的危险性评估提供依据。方法:检测2009年-2011年烟台市25600名从事食品行业的服务人员的肠道致病菌;检测方法按照国家标准GB/T4789-2003《食品卫生检验方法微生物学部分》的规定;检测菌群范围包括:沙门菌、志贺菌、豚鼠气单胞菌、致泻性大肠杆菌、溶藻弧菌、嗜水气单胞菌、霍利斯弧菌、非O1群霍乱弧菌、副溶血弧菌。结果:(1)根据生化鉴定结果表明其生化谱线符合率为93.8%～99.9%;(2)检出肠道细菌254份,阳性率为0.99%,其中弧菌科细菌为144株(含117株副溶血弧菌,12株溶藻弧菌,6株温和气单胞菌,5株非O1群霍乱弧菌,2株豚鼠气单胞菌,1株嗜水气单胞菌,1株霍利斯弧菌),占检出肠道细菌的56.69%;肠道杆菌细菌为110株(含76株沙门菌6,株志贺菌,9株致病性大肠杆菌,14株侵袭性大肠杆菌,5株产毒性大肠杆菌,占检出肠道细菌的43.30%。肠道致病菌的阳性率呈现出逐年下降的趋势,差异有显著的统计学意义;(3)检出的肠道致病菌中,以副溶血弧菌(46.06%)和沙门菌(29.90%)阳性率为最高。结论:食品行业服务人员病原菌携带的肠道致病菌以肠道弧菌为主要的病原菌。对该人群进行健康携带病原细菌调查,有利于找出微生物引起食源性疾病的关键控制点,从而采取针对性措施来规范相关人员健康检查的工作以保障食品卫生安全。     

Travellers' diarrhoea: does it occur in the United Kingdom?

Of 485 persons who replied to a questionnaire after attending a European Congress in September 1974, diarrhoea was experienced by 4 of 143 British residents and 2 of 342 visitors to the United Kingdom. This extremely low incidence of travellers'' diarrhoea contrasts with the high incidence reported in travellers from countries with cool climates and north European standards of hygiene to countries where these conditions do not hold.     

Infectious aetiologies of travelers' diarrhoea

Traveler's diarrhoea (TD) occurs in 20 to 60% of European or North-American travelers in intertropical areas. Following return from endemic zone, malaria must always be evocated in front of febrile diarrhoea. Many causative infectious agents are involved in TD and their frequency may vary according to destination and seasons. The main agents involved in TD are Escherichia coli pathovars (especially enterotoxigenic and enteroaggregative E. coli) followed by enteroinvasive bacteria (Campylobacter spp., Shigella spp., Salmonella enterica), enteric viruses (norovirus, rotavirus) and protozoa (Gardia intestinalis, Cryptosporidium parvum et Entamoeba histolytica). The development of molecular biology methods as PCR may allow us to evaluate the relative frequency of these agents and especially of viral agents in TD. Protozoa and microsporidia are more frequently isolated in persistent and chronic TD, especially in compromised patients. A complete etiological research in routine microbiology laboratories is difficult and time-consuming, related to the high diversity of causative agents and the need for specific methods. Implementation of laboratory diagnosis is highly recommended when diarrhoea is associated with fever or presence of blood in stools, immunosuppression, antibiotic treatment (Clostridium difficile toxins) or in case of persistent/chronic diarrhoea. According to the high frequency of acquired antibiotic-resistance in enteric bacteria, an antibiogram must be performed for all causative bacterial agents.     

Aetiology of diarrhoea in a birth cohort of children aged 0-2 year(s) in rural Mirzapur, Bangladesh

The incidence of aetiology-specific diarrhoea and the pathogenicity of infectious agents in a birth cohort (n=252) in rural Bangladesh were determined. Stool specimens or rectal swabs were collected from diarrhoeal cases over two years and routinely on a monthly basis. Stool samples from children with diarrhoea were compared with stool samples from children without diarrhoea to calculate rates of isolation and pathogenicity of agents. In total, 1750 stool specimens from diarrhoea patients and 5679 stool specimens from children without diarrhoea were tested. An infectious agent was identified in 58% of the stool specimens from diarrhoea patients and 21.6% of the stool specimens from children without diarrhoea. The most commonly-isolated pathogens from all specimens were enterotoxigenic Escherichia coli (ETEC), enteroadherent E. coli, Shigella, Campylobacter jejuni, Giardia, and rotavirus. ETEC (ST and LT-ST toxin), enterotoxigenic Bacteroides fragilis, Shigella, and rotavirus were associated more with disease than with asymptomatic infections. Aetiology-specific infections were associated with acute episodes. The isolated enteropathogens were essentially the same as those found in other tropical rural settings. Enterotoxigenic B. fragilis was also identified as a pathogen. Ongoing vaccine efforts focusing on Shigella, rotavirus, and ETEC would be useful.     

A two-year study of enteric infections associated with diarrhoeal diseases in children in urban Somalia

A hospital-based systematic sample of 1667 children with severe diarrhoeal disease was studied in Mogadishu, Somalia, throughout 1983 and 1984. One or more enteric pathogens were found in 61% of the patients. Rotavirus (25%), enterotoxigenic Escherichia coli (11%), Shigella spp. (9%), Aeromonas hydrophila (9%), Giardia lamblia trophozoites (8%), Campylobacter jejuni (8%), and Vibrio cholerae non-O1 (6%) were the most frequently identified pathogens. Age-specific detection rates of enteric pathogens and helminths, seasonal patterns, and relationship of some specific infections with feeding status and main clinical features have been defined for all the sample examined.     

Role of Escherichia coli in acute diarrhoea in tribal preschool children of central India

Five hundred and eighty preschool children belonging to tribal areas of Madhya Pradesh were followed up daily for the presence of diarrhoea for a period of 1 year. In all, 1236 episodes of diarrhoea were recorded with an average of 2.13 episodes per child per year. Stool samples were collected during 780 episodes. They were cultured to isolate Escherichia coli as well as non-E. coli enteropathogens. Ten different genes were detected to identify all diarrhoeagenic E. coli using multiplex polymerase chain reaction. Enteroaggregative E. coli was the commonest diarrhoeagenic E. coli and was isolated from 64 children, followed by enteropathogenic E. coli (27), enterotoxigenic E. coli (10) and enterohaemorrhagic E. coli (2). Other enteropathogens detected were bacteria such as Shigella sp, Vibrio cholerae and Salmonella sp, parasites such as Giardia lamblia and Entameba histolytica, and rotavirus. Most of the bacterial pathogens were multi-drug resistant. The study shows that diarrhoeagenic E. coli contribute significantly to the burden of acute diarrhoea in tribal preschool children.     

The association of enterotoxigenic and enteropathogenic Escherichia coli and other enteric pathogens with childhood diarrhoea in Yugoslavia

The presence of enterotoxigenic and enteropathogenic Escherichia coli (ETEC and EPEC, respectively) was investigated in stool specimens of 1082 preschool children with diarrhoea and in stools of 335 healthy controls in localities in southern Yugoslavia, as well as in 566 children with diarrhoea and in 231 controls living in northern part of the country, during the seasonal peak (August-November) of enteric diseases in 1986. ETEC were found in 114 (10.5%) children with diarrhoea and in 14 (4.2%) controls (P less than 0.001) in the southern part, and in 26 (4.6%) ill children and one (0.4%) well child (P less than 0.005) in the northern part of Yugoslavia. EPEC were isolated from stools of 85 (7.9%) children with diarrhoea and of 14 (4.2%) well children (P less than 0.05) in localities of southern Yugoslavia, and from 22 (3.9%) ill children and from 10 (4.3%) controls in northern Yugoslavia. Nineteen EPEC strains expressed localized adherence to HEp-2 tissue culture cells; all were isolated from stools of ill children. In southern Yugoslavia, where other enteropathogens were sought, the most commonly found agents in ill children were shigellae (17.5%), rotavirus (11.8%), ETEC, and EPEC. Potential pathogens were detected in 44.5% cases of sporadic diarrhoea and in 15.8% controls. This study revealed that ETEC were associated with acute diarrhoeal disease in Yugoslav preschool children. On the other hand, the diagnosis of EPEC-diarrhoea by routine determination of serogroup established the association of these agents with sporadic diarrhoea only in the 0-2 years age categories in all investigated localities. In the less developed southern part of Yugoslavia bacteria were the predominant causative agents of enteric illness during the seasonal peak of this disease.     

Randomised, double-blind, safety and efficacy of a killed oral vaccine for enterotoxigenic E. Coli diarrhoea of travellers to Guatemala and Mexico

We tested the efficacy of a killed oral vaccine for enterotoxigenic Escherichia coli (ETEC) diarrhoea to determine if two doses of vaccine with colonization factor antigens (CF) and cholera B subunit would protect against ETEC diarrhoea of travellers. Six hundred seventy-two healthy travellers going to Mexico or Guatemala were studied in a prospective, randomised, placebo-controlled trial. The primary outcome was a vaccine preventable outcome (VPO), defined as an episode of ETEC diarrhoea with an ETEC organism producing heat labile toxin (LT) or CF homologous with the vaccine, without other known causes. The vaccine was safe and stimulated anti-heat labile toxin antibodies. There was a significant decrease in more severe VPO episodes (PE=77%, p=0.039) as defined by symptoms that interfered with daily activities or more than five loose stools in a day, although the total number of VPO events did not differ significantly in the vaccine and placebo groups. We conclude that the new oral ETEC vaccine reduces the rate of more severe episodes of traveller's diarrhoea (TD) due to VPO-ETEC, but it did not reduce the overall rate of ETEC diarrhoea or of travellers' diarrhoea due to other causes.     

Etiology of acute diarrhoea among children in developing countries: a multicentre study in five countries.

A 2-year etiological survey of acute diarrhoea in children aged 0-35 months who were attending treatment facilities was carried out using a standardized protocol in five hospitals in China, India, Mexico, Myanmar, and Pakistan. A total of 3640 cases of diarrhoea and 3279 age- and sex-matched controls were studied; about 60% of the patients were aged less than 1 year and 60% were male. An enteric pathogen was detected in 68% of the cases and in 30% of the controls. In all the study centres, the pathogens most strongly associated with disease were rotavirus (16% of cases, 2% of controls), Shigella spp. (11% of cases, 1% of controls) and enterotoxigenic Escherichia coli (16% of cases, 5% of controls). Rotavirus was commonest among 6-11-month-olds, accounting for 20% of all cases in this age group; 71% of all rotavirus episodes occurred during the first year of life. Shigella spp. were commonest among those aged 12-23 months and 24-35 months, accounting for 22% and 27% of the cases, respectively. The proportion of cases that yielded no pathogen was inversely related to age, being highest (41%) among infants below 6 months of age and lowest (19%) among those aged 24-35 months. These results suggest that microbe-specific intervention strategies for the control of childhood diarrhoeal diseases in developing countries should focus on rotavirus, Shigella spp. and enterotoxigenic E. coli.     

A modified infant mouse assay for bacterial enterotoxins

The reproducibility of the infant mouse assay for Escherichia coli ST and heat-labile enterotoxins of Aeromonas spp. is improved if both intestinal weight to remaining body weight ratio (IW/RBW) and the amount of diarrhoea produced are considered as criteria for classifying enterotoxigenic strains. Animals with profuse diarrhoea may have IW/RBW ratios below the widely accepted critical value for a positive test. Using pools of supernatants from broth cultures of three different strains of E. coli, 15% of ST producers would have been regarded as negative using IW/RBW ratio as the only criterion of a positive test. In testing single supernatants, 25% of ST producing E. coli would not have been correctly classified using IW/RBW alone. A scoring system which incorporates IW/RBW ratios and the amount of diarrhoea produced improves the usefulness of the test by allowing clear separation of positive and negative strains. The scoring system is also applicable to older mice for assay of E. coli ST so that a wider age range of mice can be used allowing increased use of animal facilities.     

Increasing the viscosity of the intestinal contents stimulates proliferation of enterotoxigenic Escherichia coli and Brachyspira pilosicoli in weaner pigs

The present study was designed to evaluate the effect of increased viscosity of the intestinal digesta on proliferation of enterotoxigenic Escherichia coli and the intestinal spirochaete Brachyspira pilosicoli in weaned pigs. Pigs were fed an experimental diet based on cooked white rice (R), which was supplemented with carboxymethylcellulose (CMC; 40 g/kg diet) to increase digesta viscosity. Thirty-six piglets weaned at 21 d of age were divided into six groups, three of which were fed R and three Addition of CMC increased digesta viscosity in the ileum (P=0.01), caecum (P=0.0007) and colon (P=0.0035), without increasing indices of large intestinal fermentation. Pigs fed developed a natural infection with enterotoxigenic E. coli after weaning and had more (P<0.0001) diarrhoea than pigs fed R. Subsequent experimental infection of two groups of pigs with B. pilosicoli resulted in more (P<0.0001) colonisation in pigs fed than R. At this time, all pigs fed had wetter (P<0.0001) faeces than those fed R, irrespective of whether they were infected with B. pilosicoli, but infected pigs also had an increased (P=0.025) number of days with diarrhoea post-infection irrespective of diet. In pigs fed it was not clear to what extent the increased viscosity associated with CMC, or the concurrent infection with enterotoxigenic E. coli, was responsible for the increased proliferation of B. pilosicoli. In a second experiment, five pigs that were weaned onto an R diet were transferred onto 3 weeks later. These pigs did not develop a natural infection with enterotoxigenic E. coli after the diet change, confirming the particular susceptibility of pigs to enterotoxigenic E. coli proliferation immediately post-weaning.     

Oral cholera vaccines containing B-subunit-killed whole cells and killed whole cells only. II. Field evaluation of cross-protection against other members of the Vibrionaceae family

Because of demonstrable cross-reactivity of cellular antigens contained in B subunit-killed whole-cell (BS-WC) and killed whole-cell-only (WC) oral cholera vaccines with antigens of various non-cholera species of the family Vibrionaceae (NCV), the protection conferred by the vaccines against diarrhoea associated with NCV was evaluated during a randomized, double-blind field trial in Bangladesh. Children aged 2-15 years and women aged greater than 15 years (62,285 in number) received three doses of BS-WC vaccine, WC-only vaccine, or a placebo consisting of Escherichia coli K12 strain (K12). During 1 year of follow-up, the incidence of treated episodes of diarrhoea associated with non-cholera vibrios known to be enteric pathogens (non-01 Vibrio cholerae, V. fluvialis, V. parahaemolyticus, V. mimicus) in the placebo group was low (1.9 cases per 10,000 recipients) and identical to that for the two vaccine groups combined. The incidence (per 10,000 recipients) of treated diarrhoeal episodes associated with Aeromonas species was considerably higher, but nearly identical in the three groups (26.1 cases for BS-WC, 26.0 cases for WC; 25.9 cases for K12). Pleisiomonas shigelloides was not isolated from any participant. It is concluded that NCV other than Aeromonas were rarely isolated from diarrhoeal patients in our study population and that killed oral vaccines which were effective against cholera exhibited no detectable cross-protection against diarrhoea associated with NCV organisms.     

Toxin production and haemagglutination in strains of Escherichia coli from diarrhoea in Brescia, Italy.

Two hundred and ninety-nine different strains of Escherichia coli, isolated from 172 patients with diarrhoea and 113 healthy subjects, were examined for enterotoxin, cytotoxin and haemolysin (Hly) production and for mannose-resistant haemagglutination (MRHA) and invasive properties. Three strains proved enterotoxigenic, none enteroinvasive; cytotoxin and Hly production was shown in 25 strains from patients and in 3 from controls. Ten strains produced the cytotoxic necrotizing factor (CNF), 6 released other factors which kill cell cultures. Hly production was shown in 21 strains, 9 of which were also positive for CNF. MRHA was detected in 26% of strains from diarrhoea compared with 14% of strains from healthy people. A strong association between toxin production and MRHA was demonstrated. Serotyping results showed that the strains exhibiting virulence traits mostly belonged to serogroups commonly involved in extra-intestinal infections. The possible role of strains of E. coli showing one or more virulence factors as opportunistic pathogens in diarrhoeal diseases is discussed.