Evidence of persisting serum antibodies to Escherichia coli O157 lipopolysaccharide and Verocytotoxin in members of rural communities in England

The techniques of enzyme-linked immunosorbent assay (ELISA) and immunoblotting were used to examine a total of 1667 sera, from apparently healthy members of rural communities in England, for antibodies to the lipopolysaccharide (LPS) of Escherichia coli O157 and Verocytotoxins (VT). Twenty-nine sera from 22 individuals were shown to have antibodies specific for E. coli O157 LPS. Some of these lived on livestock farms and had occupational contact with cattle, suggesting that personnel working with farm animals may produce serum antibodies to the O157 LPS antigens. Fifteen people had IgG class antibodies to O157 LPS, suggesting long-term exposure to E. coli O157 and five people had serum antibodies on more than one occasion showing evidence of persistent antibodies to O157 LPS. Thirteen sera from 12 of 22 individuals also contained antibodies to VT1, VT2 or both toxins. Ten sera contained antibodies to VT1 and VT2, three sera contained antibodies to VT2 only.     

浙江省舟山市269例海岛渔民病毒性肝炎型别分析

为探讨海岛渔民病毒性肝炎的病毒种类及其与临床的关系，对269例海岛渔民肝炎患者的型别进行了分析。研究对象为浙江省舟山市人民医院2001年1月至2004年12月住院的269例渔民病毒性肝炎患者，均为男性，年龄18～65岁，平均32．5岁。诊断标准根据2000年9月中华医学会传染病与寄生虫病学分会、肝病学分会联合修订的病毒性肝炎防治方案。患者人院后常规进行甲、乙、丙、丁、戊、庚型肝炎血清标志物检测，采用酶联免疫吸附法，HCV—RNA，HBV—DNA（采用PCR）。     

Antimicrobial resistance patterns and plasmids of enteropathogenic Escherichia coli isolated in Nigeria

In an epidemiological study of enteropathogenic Escherichia coli, 102 strains were isolated from patients seen at the University Teaching Hospital in Lagos. The most common serotype encountered was 055 followed by 026. Antimicrobial susceptibility testing and plasmid profiling of the strains were done. All the strains were sensitive to colistin, nalidixic acid, nitrofurantoin, cefotaxime, amikacin, and augmentin. Of the 102 strains, 47 (46%) were resistant to one or more of the following antimicrobial agents: Co-trimoxazole, tetracycline, ampicillin, streptomycin, sulphonamide and a combination of ampicillin with sulbactam. All the strains that were resistant to any antimicrobial agents were also resistant to tetracycline. Seventy-two strains (70.6%) harbored plasmid whose molecular weights ranged from 0.8 to 120 × 10⁶ daltons. The majority. of the plasmid were smaller than 6 × 10⁶; 90% of strains carrying plasmid ranging in size from 2 to 6 × 10⁶ daltons and 50 to 70 × 10⁶ daltons were resistant to one or more antimicrobial agents. Trasformation and conjugation experiment showed that about 57% of the resistant strains carried R plasmid. Plasmld-determined resistance to tetracycline, ampicillin, streptomycin and sulphonamide was found.     

Emergence of Escherichia coli isolates producing conjugative plasmid-mediated DHA-1 beta-lactamase in a Korean university hospital

Seven isolates of cefoxitin-resistant Escherichia coli with an inducible phenotype were detected between November 2002 and July 2003 in a Korean hospital. Conjugations were tested by the filter mating method using azide-resistant E. coli J53 as the recipient. All isolates and their transconjugants were tested for broth microdilution minimum inhibitory concentrations, isoelectric focusing (IEF), polymerase chain reaction (PCR) for SHV, TEM, CTX-M and DHA-derived beta-lactamases, and DNA sequencing. XbaI-digested genomic DNA bands of the seven isolates were separated by pulsed-field gel electrophoresis (PFGE). IEF, PCR and sequence analysis revealed that all isolates possessed a blaTEM-1-like and a blaDHA-1 gene. Two isolates also carried the blaCTX-M-14 gene. Transfer of the resistance by conjugation experiments of all seven isolates was successful, suggesting that the blaDHA-1-containing plasmids in the E. coli isolates were self-transmissible. The isolates were recovered from patients in wards or an intensive care unit, all of which had been exposed to beta-lactams before isolation of the DHA-1 producers. Five patterns among the seven isolates were demonstrated by PFGE; sporadic infections with E. coli possessing an inducible beta-lactam resistance phenotype were found. DHA-1 encoded by conjugative plasmids conferred the resistance phenotype. The spread of the DHA-1 producers was due to both clonal spread and horizontal transfer of the resistance gene.     

Enterotoxigenic Escherichia coli associated diarrhoea among infants aged less than six months in Calcutta, India

The role of enterotoxigenic Escherichia coli (ETEC) as etiologic agents of diarrhoea in infants aged less than six months was assessed in a hospital based study in Calcutta, India. Of the 218 cases examined, ETEC strains were isolated from 26 (11.9%) cases. Among these, in 17 cases ETEC was the sole infecting pathogen (p = 0.0085). Of the 26 isolates (each isolate representing a case), 24 were distributed among seven different O:K:H serotypes and two different colonization factor antigens (CFAs) I and II. Two of the remaining isolation were untypable, non-haemagglutinating, and were nonhydrophobic as measured by the salt aggregation test (SAT). Of the 26 ETEC strains detected, 15 (57.7%) produced heat-labile toxin (LT) only, 8 (30.8%) liberated heat-stable toxin (ST) only, and the remaining 3 (11.5%) produced both LT and ST. No ETEC strain was isolated from the 102 age-matched controls included in this study. All the ETEC isolates were multiple drug resistant. The study showed that the diarrhoea due to ETEC was of brief duration, mostly within the range of 3 to 7 days.     

Virulence genotypes and serotypes of verotoxigenic Escherichia coli isolated from cattle and foods in Argentina

Virulence factors of Verotoxin-producing Escherichia coli(VTEC) strains isolated from hamburgers and ground beef were studied in Argentina by PCR. Their virulence profiles were correlated with those corresponding to strains isolated from calves and adult cattle. Most virulent profiles (VTs⁺ eae ⁺Mp⁺) were present in E. colifrom healthy and diarrheic calves corresponding to O5:H-, O5:H27, O20:H?, O26:H11, O38:H?, O103:H-, O103:H2, O111:H-, O118:H16, O165:H-serotypes. The presence of the eaegene was significantly more frequent among VTEC strains isolated from calves (20/26; 76%) than from adult cattle (1/39; 2.5%) (p< 0.005). VT2⁺ eae ^? E. coliwas prevalent in foods and adult cattle at slaughterhouse. The prevalence of the eaegene was similar between VTEC strains isolated from meat (0/21) and adult cattle (1/39; 2.5%) which constitutes the main population processed at slaughterhouses in Argentina. Serotyping showed that VTEC strains were distributed among 31 serotypes, some of which (O20:H19, O91:H21, O113:H21, O116:H21, O117:H7, O171:H2, OX3:H21) were shared between bovine and food strains. These O serogroups have been isolated from cases of haemorrhagic colitis (HC) and haemolytic-uraemic syndrome (HUS) in humans in several continental European countries. This study confirms the role of cattle as a reservoir of many VTEC serotypes other than O157:H7 and represents a base for future diagnostic, prevention and control strategies of EHEC in this country. In addition, this study affirms the advantages of PCR-based screening of E. coliisolates given the finding of so many verotoxin-producing strains.     

Prevalence and characteristics of human and bovine verotoxigenic Escherichia coli strains isolated in Galicia (north-western Spain)

An epidemiological study was carried out to determine the incidence and the serotypes of verotoxigenic Escherichia coli (VTEC) that cause infections in Galicia (north-western Spain). Although, VTEC strains were isolated from 55 (14%) of the 387 calves sampled and the majority of bovine VTEC strains belonged to serotypes (026:H11 or H–, 091:H21, 0103:H2, 0105:H18, 0111:H–, 0113:H21, 0126:H–, 0128:H– and 0157:H7 or H–) previously associated with human haemorrhagic colitis (HC) and haemolytic uraemic syndrome (HUS) in other countries, VTEC are not a common cause of human infections in Spain. Thus, VTEC (026:H11 and 086:H10) were isolated from only 3 (0.6%) of the 482 children with diarrhoea investigated. We examined the 69 (3 humans and 66 bovines) VTEC strains that were initially isolated as E. coli producing a toxin cytotoxic to Vero and HeLa cells by polymerase chain reaction (PCR) using specific primers for VT1, VT2 and eae genes. PCR showed that 38 (55%) of VTEC strains carried VT1 genes, 18 (26%) possessed VT2 genes, and 10 (14%) carried both VT1 and VT2 genes. Three (one human and two bovine) strains which were formerly VTEC had lost the ability to produce verotoxins upon subculture and became negative for VT 1 and VT2 by PCR. In total 35 (51%) of 69 VTEC strains, including the two human VT1⁺ strains of serotype 026:H11, were positive for eae sequences when tested by PCR. Presence of the eae gene was significantly more frequent (100%; 21/21) among VTEC strains with serotypes (026:H11, 0111:H–, 0157:H–and 0157:H7) considered as enterohaemorrhagic E. coli (EHEC) than among VTEC strains with non-EHEC serotypes (29%; 14/48) (p < 0.001). Results obtained in this study indicate that cattle may be an important source of VTEC involved in human disease. However, severe clinical syndromes caused by VTEC, such as HC and HUS, are uncommon in Spain, in comparison with North America and the UK. In any case, VTEC disease can appear on the scene very suddenly, as occurred in the UK and North America in the 1980s.     

Characterisation of strains of enteroaggregative Escherichia coli isolated during the infectious intestinal disease study in England

Strains of Escherichia coli, hybridising with a DNA probe for enteroaggregative E. coli (EAggEC), were isolated from patients with infectious intestinal disease (IID) or gastro-enteritis, and healthy controls during the study of IID in England. Of 3506 cases presenting with an IID, 160 (4.6%) had faecal EAgg-EC as compared with 46 (1.7%) of 2772 healthy controls, 53% of EAggEC isolated from each of the case and the control groups adhered in a stacked-brick formation. Strains from cases and controls belonged to over 39 and 14 different serogroups respectively, and approximately half of the strains isolated did not react with antisera in the current somatic antigen serotyping scheme. Forty-nine cases with EAggEC (31%) had a known history of foreign travel. Over 50% of strains isolated from cases and controls were resistant to one or more of eight antimicrobials, and antimicrobial resistance was not statistically significantly more common among cases with a known history of foreign travel (p = 0.57). These data form part of the largest investigation carried out on these organisms in the UK to date and provide the most comprehensive analysis of strains of EAggEC isolated from the general population of England.     

浙江省腹泻患者致泻性大肠埃希菌血清型分布及其鉴定效率的评价

目的 了解浙江省致泻性大肠埃希菌（DEC）血清型分布并探讨其血清学鉴定分类方法的鉴定效率。方法 对2009年7月至2013年6月浙江省腹泻症候群病原谱监测网络菌株库中的696株DEC菌株（通过毒力基因鉴定）开展血清学凝集试验,比较毒力基因和血清学鉴定分类的结果。结果 696株DEC中288株（41.4%）能明确O抗原型别,分属于35种O血清群。171株（24.6%）H血清凝集,分属于21种H型。肠集聚性大肠埃希菌（EAEC）、产肠毒素性大肠埃希菌（ETEC）、肠致病性大肠埃希菌（EPEC）和肠出血性大肠埃希菌（EHEC）凝集率分别为31.9%（130/408）、70.6%（127/180）、31.5%（29/92）和14.3%（2/14）,分属于30、18和15种O血清群,1株EHEC为O157∶H7。EAEC和EPEC血清群相对较多样化,而ETEC则相对集中,不同类型DEC可具有同一血清群/型。根据血清学结果可分类的75株DEC中,42株毒力基因和血清学分类结果一致,33株不一致。结论 浙江省DEC血清群/型种类多样,单纯采用血清学筛查可造成极大的漏检或误分,建议采用毒力基因鉴定分类。     

An epidemiological study on Verotoxin-producing Escherichia coli (VTEC) infection among population of northern region of Iran (Mazandaran and Golestan provinces)

Faecal samples from 3268 randomly selected inhabitants of two provinces in the northern region of Iran were screened to detect Verotoxin-producing Escherichia coli (VTEC) using colony sweep polymyxin-B extraction method. Non-sorbitol fermentation phenotype and slide agglutination with O157 and H7 antisera used to detect this serotype. We found that 0.7% of the population were infected with VTEC, however none of the isolates belonged to O157:H7 serotype. We also found that children < 6 years of age were at highest risk of infection with VTEC (p < 0.05). Moreover, a significant association was found between the VTEC and diarrhoeal cases at the same age group (p < 0.001). Overall distribution of the VTEC isolates in the general population was found to be random, though a kind of clustered distribution could be noticed.     

三对引物同时PCR分型检测产毒素大肠杆菌的方法及在分子流行病学研究中的应用

在产毒素大肠杆菌肠毒素基因内设计合成三对引物，建立了三对引物同时ＰＣＲ检测ＥＴＥＣ的方法，一次ＰＣＲ即可扩增出６２７ｂｐ（ＬＴｈ）、２４０ｂｐ（ＳＴ Ｉａ）和１６９ｂｐ（ＳＴ Ｉｂ）三种肠毒素基因片段，可同时分型检测出ＬＴｈ，ＳＴ Ｉａ、ＳＴ Ｉｂ、ＬＴｈ－ＳＴ Ｉａ、ＬＴｈ－ＳＴ Ｉｂ五种基因型的ＥＴＥＣ，与非ＥＴＥＣ对照菌无交叉反应，最小检出量为１０ｃｆｕ，显示了很高的特异性和敏感性。将建立的     

Verocytotoxin-producing Escherichia coli, Japan, 1999-2004

In 1999, an infectious disease prevention law was enacted in Japan that affected the nationwide infectious surveillance system. A total of 19,304 laboratory-confirmed verocytotoxin-producing Escherichia coli cases were reported through 2004. The annual incidence was 2.74/100,000 population; its fluctuation over time and space was associated with climate, socioeconomic, and population factors.     

Enterotoxigenic and necrotizing Escherichia coli in human diarrhoea in Spain

Enterotoxigenic Escherichia coli (ETEC) strains of serotype 0153: K-:H45 CFA/I⁺ STa⁺ were associated with two outbreaks of neonatal diarrhoea that occurred in two different hospitals of Madrid, in one of which several children died. Two other outbreaks were associated with ETEC strains of serotypes 0159: K-: H21 (LT⁺) and 0159: K-: H4 (LT⁺ STa⁺) without CFA/I and CFA/II colonization factors. Necrotizing E. coli (NTEC) strains of serotype 06: K13, producing the cytotoxic necrotizing factor CNFI and -haemolysin, were also associated with two outbreaks of neonatal diarrhoea that occured in a hospital in Madrid and in a hospital in Talavera de la Reina. The results of the characterization of some ETEC and NTEC strains isolated from sporadic cases of diarrhoea are also discussed.Corresponding author.     

Detection of Escherichia coli O157:H7 and other intestinal pathogens in patients with diarrhoeal disease

Six hundred and six faeces specimens from patients with diarrhoea, aged 0–>60 and living in the area of Fano (Italy), were examined for Escherichia coli 0157:H7, Salmonella, Shigellaand thermophilic Campylobacterspp. E. coli 0157:H7 was not found, confirming the limited circulation of this bacterium in our country. On the other hand, Salmonellae were the most frequent pathogens (5.6%), followed by Campylobacters (2.3%) and Shigellae (0.3%).     

广西首次发现食品中集聚性大肠杆菌

目的：了解食品中肠集聚性大肠杆菌污染状况。方法：对127份食品标本进行EaggEC分离，用EaggEC特异性引物进行分子生物学鉴定，并进行小鼠毒力试验。结果：自田螺及生葱各分离出一株EaggEC，分别引起实验小鼠66.67％和33.33％死亡。结论：研究结果表明食品中存在EaggEC污染，从中分离到的EaggEC有较强的毒力。     

Antimicrobial-resistant invasive Escherichia coli, Spain

Surveillance System. A network of 32 Spanish hospitals, serving approximately 9.6 million persons, submitted antimicrobial-susceptibility data on 7,098 invasive Escherichia coli species (2001-2003). Resistance to ampicillin, cotrimoxazole, ciprofloxacin, gentamicin, and tobramycin was found at rates of 59.9%, 32.6%, 19.3%, 6.8%, and 5.3%, respectively. Resistance to multiple drugs increased from 13.8% in 2001 to 20.6% in 2003 (p <0.0001). Antimicrobial consumption data were obtained from the Spanish National Health System. In spite of decreased cephalosporin and beta-lactam use, overall extended-spectrum beta-lactamase production increased from 1.6% (2001) to 4.1% (2003) (p <0.0001), mainly due to the rising prevalence of cefotaximases. Resistance to ciprofloxacin significantly increased, mostly in community-onset infections, which coincided with a rise in community quinolone use. Cotrimoxazole resistance remained stable at approximately 30%, even though its use was dramatically reduced.     

A systematic review of experimental infections with enterotoxigenic Escherichia coli (ETEC)

Volunteer challenge with enterotoxigenic Escherichia coli (ETEC) has been used for four decades to elucidate the pathogenesis and immune responses and assess efficacy of various interventions. We performed a systematic review of these studies and a meta-analysis of individual patient-level data (IPD) from a subset of studies using standard methodology.We identified 27 studies of 11 ETEC strains administered to 443 naive subjects at doses from 1 × 10⁶ to 1 × 10¹⁰ colony forming units (cfu). Diarrhea attack rates varied by strain, dose and enterotoxin. Similar rates were seen at doses of 5 × 10⁸ to 1 × 10¹⁰ cfu with the three most commonly used strains B7A, E24377A, H10407. In IPD analysis, the highest diarrhea attack rates were seen with strains B7A, H10407 and E24377A. The H10407 induced significantly higher stool output than the other strains. Additionally, the rate of output was different across strains.The risk of diarrhea, abdominal cramps, nausea and headaches differed significantly by ETEC strain. An increased risk of nausea, abdominal cramps and headaches was seen for females. Baseline anti-LT IgG titers appeared to be associated with a decrease risk of diarrhea outcomes, a trend not seen with anti-LT IgA or seen consistently with anti-colonization factor antibodies. Neither early antibiotic treatment nor diarrhea duration significantly affected the frequency or magnitude of serologic responses.These studies have served as an invaluable tool in understanding disease course, pathogenicity, innate immune responses and an early assessment of product efficacy. When designing and planning experimental ETEC infection studies in this age of increased ethical scrutiny and growing appreciation of post-infectious sequelae, better understanding of available data is essential.     

Effects of Japan Sea Proper Water on the growth ofLegionella pneumophila, Escherichia coli, andStaphylococcus aureus

Objective To assess whetherLegionella pneumophila serogroup 1 and serogroup 6,Escherichia coli, andStaphylococcus aureus can survive in Japan Sea Proper Water (JSPW). Methods The inhibitory effects of JSPW, surface seawater (SSW), phosphate buffer solution with 3.5% NaCl of pH 7.0 (3.5% NaCIPBS), and the 10²- and 10⁴-fold dilute solutions with purified water or phosphate buffer solution of pH 7.0, and purified water were investigated. Survival cells were counted immediately after the water and the bacteria were mixed, and at 1,3,5, and 7 days after incubation at 37°C. If the number of surviving cells was decreased more than 2 log units compared with the starting value, we judged the medium to have had an inhibitory effect on the growth of the bacteria. Results The survival cells of the bacteria in JSPW had decreased more than 2 log units compared with the starting value at 1 day after incubation. After 1 day of incubation, the cells ofLegionella pneumophila serogroup 6 andStaphylococcus aureus were found to have decreased more than 2 log units in purified water (PW) used as a control. Furthermore,Legionella pneumophila serogroup 1 in the 10²-fold dilute solution of JSPW was only 1.04 log units lower than the starting value at 7 days after incubation. In the 10²- and 10⁴-fold dilute solutions of JSPW,Escherichia coli survived for 7 days after incubation. These results were almost similar to the results in SSW and 3.5% NaCIPBS. Conclusions The present findings demonstrate thatLegionella pneumophila serogroup 1 andEscherichia coli cannot survive in undiluted JSPW for over a day at 37°C, suggesting the inhibitory effects may be due to the sodium chloride contained in JSPW.