Infection with verocytotoxin-producing Escherichia coli O157 during a visit to an inner city open farm

Two cases of Escherichia coli O157 infection occurred in children after visiting an inner city open farm. Subsequently faecal samples collected from animal pens and samples of composted mixed animal manure and vegetable waste were examined for E. coli O157 by enrichment culture, immunomagnetic separation and culture of magnetic beads to cefixime tellurite sorbitol MacConkey agar. Strains of E. coli O157 were characterized by hybridization with DNA probes for VT1, VT2 and eaeA, plasmid profile analysis, phage typing and pulsed field gel electrophoresis (PFGE). Verocytotoxin-producing E. coli O157 strains were isolated from faecal samples from a cow, a horse, 3 breeds of pigs, 2 breeds of sheep and 2 breeds of goats and from 2 samples of compost which had been processed for 3 months. All strains were phage type 21, hybridized with probes for VT2 and eaeA but not with one for VT1, harboured 92 and 2 kb plasmids and gave indistinguishable banding patterns with PFGE. Although only two culture-confirmed cases of infection had been identified, the farm had over 100,000 visitors per year and so it was closed as a precaution both to allow a thorough investigation and to prevent further cases. The investigation identified many factors which may have contributed to transmission of E. coli O157 infection. Most of these were readily resolved by appropriate corrective measures and as there were no further cases associated with the farm during the ensuing 4 weeks it then re-opened. These cases highlight the risk, especially to young children, of acquiring zoonotic infections during visits to open farms and emphasize the need for adequate guidance and supervision before and during such visits.     

Large outbreak of verocytotoxin-producing Escherichia coli O157 infection in visitors to a petting farm in South East England, 2009

In the summer of 2009, an outbreak of verocytotoxigenic Escherichia coli O157 (VTEC O157) was identified in visitors to a large petting farm in South East England. The peak attack rate was 6/1000 visitors, and highest in those aged <2 years (16/1000). We conducted a case-control study with associated microbiological investigations, on human, animal and environmental samples. We identified 93 cases; 65 primary, 13 secondary and 15 asymptomatic. Cases were more likely to have visited a specific barn, stayed for prolonged periods and be infrequent farm visitors. The causative organism was identified as VTEC O157 PT21/28 with the same VNTR profile as that isolated in faecal specimens from farm animals and the physical environment, mostly in the same barn. Contact with farm livestock, especially ruminants, should be urgently reviewed at the earliest suspicion of a farm-related VTEC O157 outbreak and appropriate risk management procedures implemented without delay.     

Transmission of Vero cytotoxin producing Escherichia coli O157 infection from farm animals to humans in Cornwall and west Devon

A study of Vero cytotoxin producing Escherichia coli (VTEC) O157 infections in Cornwall and West Devon was conducted to identify associations between human infection and contact with farm animals. In three years from November 1994 to October 1997, 63,000 stool specimens were submitted to four participating microbiology laboratories and screened for E. coli O157. Sixty-nine confirmed cases were interviewed to assess the extent of any direct or indirect contact with farm animals. Nine out of 22 investigations conducted on farms--in which animal rectal swabs, faecal specimens, fore-stream milk samples (first draw-off from teats), and various environmental samples were tested--yielded VTEC O157. In seven incidents one or more isolates from animals were indistinguishable from the isolate(s) from the human case(s) using phenotypic and genotypic subtyping. Cases associated with animal contact included farm visitors, holidaymakers, and members of farming families and farm workers.     

Vero cytotoxin-producing Escherichia coli O157 gastroenteritis in farm visitors,North Wales

An outbreak of Vero cytotoxin-producing Escherichia coli O157 (VTEC O157) gastroenteritis in visitors to an open farm in North Wales resulted in 17 primary and 7 secondary cases of illness. E. coli O157 Vero cytotoxin type 2, phage type 2 was isolated from 23 human cases and environmental animal fecal samples. A case-control study of 16 primary case-patients and 36 controls (all children) showed a significant association with attendance on the 2nd day of a festival, eating ice cream or cotton candy (candy floss), and contact with cows or goats. On multivariable analysis, only the association between illness and ice cream (odds ratio [OR]=11.99, 95% confidence interval [CI] 1.04 to 137.76) and cotton candy (OR=51.90, 95% CI 2.77 to 970.67) remained significant. In addition to supervised handwashing, we recommend that foods on open farms only be eaten in dedicated clean areas and that sticky foods be discouraged.     

Swimming-associated outbreak of Escherichia coli O157:H7

In 1997 the first outbreak of Escherichia coli O157:H7 infections involving 14 cases occurred in Finland. A case was defined as a resident of Alavus with an episode of diarrhoea between 5 and 17 July 1997, and from whom E. coli O157:H7 was isolated from stool. The investigation included case searching and a population-based case control study. Five primary and eight symptomatic secondary cases of E. coli O157:H7 illness were detected. In the 10 days before the outbreak, all 5 primary patients (aged 3-8 years), but only 6 of 32 population controls from the same age range (Fisher's test, P < 0.001) and 4 of 10 sibling controls (P < 0.05) had visited (but had not necessarily bathed in) a shallow beach popular among young children. Four out of 5 primary cases had remained within 5 m of the beach while swimming and had swallowed lake water compared to 1 of 5 population controls. These analytical epidemiologic findings incriminated fresh lake water as the vehicle of E. coli O157:H7 transmission.     

Epidemiology of infection due to Escherichia coli O157: a 3-year prospective study.

A 3-year study of Escherichia coli infections in Grampian Region was conducted to ascertain the incidence, document clinical sequelae and identify at-risk groups. Approximately 30,000 stools from patients with acute diarrhoea were screened for E. coli O157, and an epidemiological questionnaire filled in for each patient whose stool was positive. Eighty-three patients were studied. The annual incidence was 6 per 100, 000. Proportionately more infections occurred in people involved in agriculture. Evidence was seen of case-to-case transmission, and contamination of a water supply. Eight cases developed haemolytic uraemic syndrome (HUS). There were 2 deaths due to HUS and 2 due to haemorrhagic colitis (HC). Symptomatic E. coli infection is relatively common in the Grampian Region, more common in the agricultural community, and is the main cause of HUS in this Region.     

Shiga toxin-producing Escherichia coli infections associated with hemolytic uremic syndrome,Italy, 1988-2000

The mean annual incidence of hemolytic uremic syndrome in persons 相似文献   

A waterborne outbreak of Escherichia coli O157:H7 infections and hemolytic uremic syndrome: implications for rural water systems

In the summer of 1998, a large outbreak of Escherichia coli O157:H7 infections occurred in Alpine, Wyoming. We identified 157 ill persons; stool from 71 (45%) yielded E. coli O157:H7. In two cohort studies, illness was significantly associated with drinking municipal water (town residents: adjusted odds ratio=10.1, 95% confidence intervals [CI]=1.8-56.4; visitors attending family reunion: relative risk=9.0, 95% CI=1.3-63.3). The unchlorinated water supply had microbiologic evidence of fecal organisms and the potential for chronic contamination with surface water. Among persons exposed to water, the attack rate was significantly lower in town residents than in visitors (23% vs. 50%, p<0.01) and decreased with increasing age. The lower attack rate among exposed residents, especially adults, is consistent with the acquisition of partial immunity following long-term exposure. Serologic data, although limited, may support this finding. Contamination of small, unprotected water systems may be an increasing public health risk.     

Shiga-toxigenic Escherichia coli O157 in agricultural fair livestock, United States

Agricultural fairs exhibiting livestock are increasingly implicated in human Shiga-toxigenic Escherichia coli O157:H7 (STEC O157:H7) outbreaks. To estimate livestock STEC O157:H7 prevalence at US fairs, we collected 2,919 fecal specimens at 29 county fairs in 2 states and at 3 state fairs in 2002. Fly pools were also collected. STEC O157:H7 was isolated from livestock at 31 (96.9%) of 32 fairs, including 11.4% of 1,407 cattle, 1.2% of 1,102 swine, 3.6% of 364 sheep and goats, and 5.2% of 154 fly pools. Cattle, swine, and flies at some fairs shared indistinguishable STEC O157:H7 isolate subtypes. In 2003, a total of 689 ambient environmental samples were collected at 20 fairgrounds 10-11 months after 2002 livestock sampling while fairgrounds were livestock-free. Four beef barn environmental samples at 3 fairgrounds yielded STEC O157:H7. These data suggest that STEC O157 is common and transmissible among livestock displayed at agricultural fairs and persists in the environment after the fair.     

The surveillance of vero cytotoxin-producing Escherichia coli O157 in Wales, 1990 to 1998.

Population-based surveillance for Vero cytotoxin-producing Escherichia coli (VTEC) O157 has been carried out in Wales since 1990. The annual incidence has remained stable during the 9-year period (mean: 1.6 cases per 100,000 population); the rate is highest in children younger than 5 years of age. Blood in the stool is reported in fewer than half the cases, indicating the importance of screening all fecal specimens for VTEC O157.     

东台市肠出血性大肠埃希菌O157感染监测

目的为掌握肠出血性大肠埃希菌O157在东台市家禽、家畜中的带菌,腹泻病人中的感染和自来水厂水源水中的污染情况.方法2000-2002年,分别在流行季节采集家禽、家畜和腹泻病人粪便及自来水厂水源水,应用免疫磁珠浓集、山梨醇麦康凯平板分离、生化和血清学反应进行鉴定.结果3年间东台市采集的6种动物粪便有4种中检出肠出血性大肠埃希菌O157,其阳性率牛为11.32%、羊为10.58%、猪为9.35%、鸡为7.73%.腹泻病人的阳性率为1.57%.采集的178份自来水厂水源水、60只苍蝇标本中均未分离出肠出血性大肠埃希菌O157.3株自动物粪便分离株具有至少2种混合型毒力基因.75株肠出血性大肠埃希菌O157菌株对15种抗生素存在不同的耐药率.结论东台市家禽、家畜和腹泻病人中存在肠出血性大肠埃希菌O157感染,且存在流行的潜在危险.     

呼和浩特市食品中大肠埃希氏菌O157∶H7污染状况调查

目的 本次研究旨在通过对呼市居民主要的消费食品进行大肠埃希氏菌O157∶H7的污染调查,从而掌握该菌对食品的污染情况.方法 随机抽取超市、农贸市场、酒店、食品店出售的食品共计15种307份,采用国标法进行检测.结果 349份食品中,检测出2株大肠埃希氏菌O157∶H7,检出率为0.57％.其中生畜肉检出1株,检出率1.32％;米粉、盒饭类食品检出1株,检出率3.57％;其余食品均未检出.结论 生畜肉,米粉、盒饭类食品中均检出大肠埃希氏菌O157∶H7.提示存在发生食源性大肠埃希氏菌O157∶H7病的潜在危险.     

Risk factors for sporadic cases of Escherichia coli O157 infection: the importance of contact with animal excreta.

To determine environmental risk factors for sporadic E. coli O157 infection in Scotland we undertook a prospective, matched case-control study between 1 October 1996 and 31 March 1999. One hundred and eighty-three cases and 545 matched controls were recruited. Contact with animal faeces (OR = 3.65; 95% CI 1.81, 7.34: P < 0.0005) and likely contact with animal faeces (OR = 4.8; 95% CI 2.42, 9.48; P < 0.0005) emerged as strong risk factors for infection. Certain exposures (mainly food-related) were inversely associated with infection i.e. were statistically protective. Most striking was the consumption of bottled water (OR = 0.28; 95% CI 0.15, 0.52; P < 0.0005). Transmission of E. coli O157 does not occur simply through contaminated food. Members of the public need to be aware of the potential for acquiring E. coli O157 through contamination of the environment with animal faeces so that they may take measures to mitigate their risk.     

Persistence of Escherichia coli O157:H7 in dairy cattle and the dairy farm environment.

The persistence of Escherichia coli O157:H7 in cattle and the farm environment was investigated on eight Ontario dairy farms positive for E. coli O157:H7 in a longitudinal study commenced one year previously. Faecal samples from cows, calves, humans, cats, rodents, wild birds, a composite fly sample and numerous composite and individual environmental samples were cultured and tested for verotoxin-producing E. coli (VTEC). VTEC isolates were serotyped and E. coli O157:H7 isolates were phage typed. E. coli O157:H7 phage type 34 was isolated from one calf on each of two farms. The same phage type had been isolated on one of these farms 12 months earlier. Most E. coli O157:H7-positive animals and farms became culture-negative within 2 and 3 months, respectively. E. coli O157:H7 was not isolated from any environmental samples, although evidence of VTEC was found in composite samples from calf feeders (19.1%), calf barn surfaces (18%), cow feeders (14.9%), flies (12.5%), cow barn surfaces (11.3%), and individual milk filters (12.5%). VTEC belonging to 21 non-O157 serotypes were isolated from 24 cows (8.2%), 21 calves (18.3%), 2 cow feeder samples (3.0%), and 1 calf feeder sample (4.8%). Shedding of E. coli O157:H7 by infected dairy cattle appears to be transient and persistence of E. coli O157:H7 was not demonstrated from the farm environment sites tested.     

致泻性大肠埃希菌在腹泻患者及家禽畜中的分布状况研究

目的：了解致泻性大肠埃希菌在我市腹泻病人及家禽、家畜，肉制品中的带菌状况及血清型分布，通过耐药性试验及相关因素分析，找出防制措施。方法：用改良EC肉汤进行增菌，用EMB和O157：117专用培养基进行致泻性大肠埃希菌的分离、培养，用生物梅里埃E生化及血清学进行鉴定，用KB法作药敏试验。结果：从198例腹泻病人中检P20出78株致泻性大肠埃希菌(45．90％)、从312个家禽中检出95株(30．45％)、从248例家畜中检出50株(20．16％)、从171例肉制品中检出20株(11．69％)。检出的致泻性大肠埃希菌共有10个血清型且存在不同程度的耐药性。结论：在腹泻病人中，致泻大肠埃希菌的感染率高达45．90％，家禽、家畜及肉制品中的带菌率也高达22．56％，且人、畜、禽的带染菌型基本一致。90％的分离菌株具有广泛的耐药性。     

Surveillance of Escherichia coli O157 isolation and confirmation, United States, 1988

In 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.     

Vero cytotoxin-producing Escherichia coli, particularly serogroup O 157, associated with human infections in the United Kingdom: 1989-91.

This survey reports the results of investigations performed by the Laboratory of Enteric Pathogens (LEP), to identify evidence of human infection with Vero cytotoxin-producing Escherichia coli (VTEC) in the UK during the period 1989-91. Bacterial isolates, faecal specimens and serum samples were received from patients suffering from diarrhoea, bloody diarrhoea and haemolytic uraemic syndrome. Using serotyping, Vero cytotoxin gene probing and an ELISA for serum antibodies to E. coli O 157, evidence of infection was detected in 232, 428 and 615 individuals in 1989, 1990 and 1991 respectively. Of these individuals, 15% were reported as having HUS. Vero cytotoxin-producing E. coli O 157 was the most frequently encountered serogroup, with isolations from a total of 1092 individuals over the 3-year period. The incidence of VTEC infection increased from 0.41/100,000 in 1989 to 1.07/100,000 in 1991. The area with the highest rate of infection in each year was Scotland, increasing from 1.37/100,000 in 1989 to 3.97/100,000 in 1991.     

河南省睢县一起腹泻后并发急性肾功能衰竭爆发的调查

目的 调查大肠埃希菌O157：H7感染性腹泻的分布特征，临床特点及家畜、家禽的带菌状况和外环境污染程度，方法 用现患调查方法，描述大肠埃希菌O157：H7感染性腹泻的发病情况，分析引起流行的原因，用O157特异性筛查方法进行病原体分离培养，应用分子生物学，微生物学，细胞学技术进行病人，家畜、家禽的病原学分离，培养，毒素因子测定。结果 睢县是河南省首先发现的疫区，从3月17日至7月6日共发生病人35例，合并急性肾功能衰竭32例，死亡28例，病死率87.50%，60岁以上发病占91%；从家畜，家禽分离出107株O157：H7菌株，从腹泻病人中分离出48株；微生物学，分子生物学及细胞学技术鉴定67株具有毒素基因；显示有5个毒素因子组合型。结论 大肠埃希菌O157：H7感染性腹泻并发急性肾功能衰竭是病人死亡的主要原因，家畜、家禽的高速 菌率可通过污染水，食物传染给人，亦可通过蝇和日常生活接触感染，睢县疫情是一起大肠埃希菌O157：H7感染引起的溶血性尿毒综合征的爆发。     

Outbreaks of Escherichia coli O157:H7 associated with petting zoos--North Carolina, Florida, and Arizona, 2004 and 2005

During 2004-2005, three outbreaks of Escherichia coli O157:H7 infections occurred among agricultural fair, festival, and petting zoo visitors in North Carolina, Florida, and Arizona. One hundred eight cases, including 15 cases of hemolytic uremic syndrome (HUS), were reported in the North Carolina outbreak; 63 cases, including seven HUS cases, were reported in the Florida outbreak; and two cases were reported in Arizona. No fatalities occurred. Illnesses primarily affected children who visited petting zoos at these events. This report summarizes findings from these outbreak investigations, which indicated the need for adequate control measures to reduce zoonotic transmission of E. coli O157:H7.     

A cluster of Escherichia coli O157: nonmotile infections associated with recreational exposure to lake water

OBJECTIVES: To identify cases and determine risk factors for an outbreak of Escherichia coli (E. coli) O157: nonmotile (NM) infections in children attending a summer day care program in California. METHODS: The authors conducted a retrospective cohort study; the cohort comprised first and second graders who attended the day care program during the last week in August 1999. Shiga toxin testing and molecular subtyping using pulsed-field gel electrophoresis were performed on isolates. Lake water, lake bottom sediment samples, and waterfowl feces from the lake environs were cultured for E. coli O157. RESULTS: Three cases of Shiga toxin-producing E. coli O157: NM infections with matching pulsed-field gel electrophoresis patterns and four probable cases were found. Children who swallowed more than a mouthful of water had a higher attack rate than those who swallowed less than a mouthful or none at all (43% vs. 10%, relative risk = 4.43, 95% confidence interval 1.12, 17.50). CONCLUSIONS: E. coli O157: NM infections were associated with swallowing water from a freshwater lake. Potential sources of contamination include feces from humans, cattle, or deer. This outbreak illustrates the value in screening patients with diarrhea for E. coli O157, submitting isolates to public health laboratories, and using molecular techniques to identify related cases. Outbreaks associated with contaminated freshwater could be averted by prevention and early detection of contamination.