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正大肠埃希菌是人和动物肠道的正常菌群,其中有些菌株可引起轻微腹泻或严重腹泻,有的菌株能引起致死性并发症,如溶血性尿毒综合征。依据血清型、毒力和临床症状的不同,将大肠埃希菌分为5类,即肠致病性大肠埃希菌、肠产毒性大肠埃希菌、肠侵袭性大肠埃希菌、肠集聚性大肠埃希菌和肠出血性大肠埃希菌。引起肠道感染的大肠埃希菌与正常菌群中的大肠埃希菌在普通平板上的表现相似,分离培养后可通过血清分型和毒力检测等加以鉴别。 相似文献
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在日本的集约化肉牛业中,犊牛腹泻是经济上的一个重大难题。就病因学而言,虽然它是由多种病原菌感染而引起的一种复杂疾病,但是肠道致病性大肠埃希氐菌(EPEC)已证明是本病的主要病原。由肠道致病性大肠埃希氐菌所致的疾病,以是微生物固定在小肠粘膜表面并产生肠毒素为特征。固定是由特殊纤毛传递的。就固定因子而言,在动物的肠 相似文献
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《动物医学进展》2016,(3)
湖北石首麋鹿国家级自然保护区是我国三大麋鹿保护基地之一,自然放养状态的麋鹿易受到大肠埃希菌侵袭并导致死亡。为了弄清石首麋鹿保护区内麋鹿大肠埃希菌感染和流行现状,以及致病性和主要毒力因子,通过药敏试验、生化鉴定、16SrDNA PCR、小鼠毒力试验等方法从病料中分离到15株致病性大肠埃希菌。药敏试验结果显示,分离到的15株大肠埃希菌对庆大霉素、卡那霉素、头孢唑啉的敏感度均达到了100%;其次是对氯霉素、新霉素以及链霉素敏感度均超过60%;耐药性方面,对克林霉素和磺胺嘧啶的耐药度分别为80%和60%。毒力因子PCR结果显示,主要毒力因子为ompA(100.00%)、traTa(80.00%)、iss(80.00%)、iucD(60.00%)、irp2(53.33%)、sta(33.33%)、cva/cvi(26.67%)、vat(20.00%)。 相似文献
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大肠杆菌可分为致病性大肠杆菌和非致病性大肠杆菌两类,致病性大肠埃希氏菌主要经畜禽的消化道而感染,在畜禽中可以引起多种综合症,对畜牧业养殖业的健康发展造成了很大损失[1]。而致病性大肠埃希氏菌的某些血清型能够引起新生和幼龄动物的肠道传染病,临床表现以腹泻、败血症、 相似文献
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携带耶尔森强毒力岛的大肠埃希菌耐药性及其对雏鸭的致病性试验 总被引：1，自引：0，他引：1
为了解105株动物源携带耶尔森强毒力岛的大肠埃希菌耐药状况和致病性,分别对各分离菌进行28种抗菌药物的敏感性测定,并选择不同毒力基因型的10株大肠埃希菌进行雏鸭的致病性试验.结果表明,分离菌对四环素、多西环素、氨苄西林、阿莫西林、复方磺胺甲(噁)唑、链霉素耐药性较高,耐药率均在80%以上;敏感率在80%以上的药物有头孢... 相似文献
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Chitrita Debroy Elisabeth Roberts Bhushan M Jayarao Jason W Brooks 《Journal of veterinary diagnostic investigation》2008,20(5):661-664
Extraintestinal pathogenic Escherichia coli (ExPEC) strains carrying distinct virulence attributes are known to cause diseases in humans and animals and infect organs other than the gastrointestinal tract. A fatal case of bronchopneumonia in a 12-year-old female Quarterhorse was investigated. Following postmortem examination, E. coli, Enterococcus sp., and Klebsiella pneumonia were isolated from the lungs, which contained multifocal intra-alveolar accumulations of neutrophils and macrophages with edema, hemorrhage, and fibrin. The strain of E. coli belonged to O2H21 and carried virulence genes cnf1, sfa, foc, fimA, and papG allele I that are known to be associated with ExPEC strains. The strain was resistant to several antimicrobials including clindamycin, erythromycin, oxacillin, penicillin, and rifampin. This is the first report, to the authors' knowledge, in which ExPEC O2H21 has been associated with fatal bronchopneumonia in a horse. 相似文献
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Escherichia coli isolates from commercial chicken meat and eggs cause sepsis,meningitis and urinary tract infection in rodent models of human infections 
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下载免费PDF全文 The zoonotic potential of Escherichia coli from chicken‐source food products is important to define for public health purposes. Previously, genotypic and phenotypic screening of E. coli isolates from commercial chicken meat and shell eggs identified some E. coli strains that by molecular criteria resembled human‐source extraintestinal pathogenic E. coli (ExPEC). Here, to clarify the zoonotic risk of such chicken‐source E. coli, we compared selected E. coli isolates from chicken meat and eggs, stratified by molecularly defined ExPEC status, to human‐source ExPEC and to laboratory E. coli for virulence in rodent models of sepsis, meningitis and UTI, and evaluated whether specific bacterial characteristics predict experimental virulence. Multiple chicken‐source E. coli resembled human‐source ExPEC in their ability to cause one or multiple different ExPEC‐associated infections. Swimming ability corresponded with urovirulence, K1 capsule corresponded with ability to cause neonatal meningitis, and biofilm formation in urine corresponded with ability to cause sepsis. In contrast, molecularly defined ExPEC status and individual genotypic traits were uncorrelated with ability to cause sepsis, and neither complement sensitivity nor growth in human urine corresponded with virulence in any infection model. These findings establish that chicken‐derived food products contain E. coli strains that, in rodent models of multiple human‐associated ExPEC infections, are able to cause disease comparably to human‐source E. coli clinical isolates, which suggests that they may pose a significant food safety threat. Further study is needed to define the level of risk they pose to human health, which if appreciable would justify efforts to monitor for and reduce or eliminate them. 相似文献
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Ulrike Lyhs Ilona Ikonen Tarja Pohjanvirta Kaisa Raninen P?ivikki Perko-M?kel? Sinikka Pelkonen 《Acta veterinaria Scandinavica》2012,54(1):64
Background
Extraintestinal pathogenic Escherichia coli bacteria (ExPEC) exist as commensals in the human intestines and can infect extraintestinal sites and cause septicemia. The transfer of ExPEC from poultry to humans and the role of poultry meat as a source of ExPEC in human disease have been discussed previously. The aim of the present study was to provide insight into the properties of ExPEC in poultry meat products on the Finnish retail market with special attention to their prevalence, virulence and phylogenetic profiles. Furthermore, the isolates were screened for possible ESBL producers and their resistance to nalidixic acid and ciprofloxacin was tested.Methods
The presence of ExPEC in 219 marinated and non-marinated raw poultry meat products from retail shops has been analyzed. One E. coli strain per product was analyzed further for phylogenetic groups and possession of ten virulence genes associated with ExPEC bacteria (kpsMT K1, ibeA, astA, iss, irp2, papC, iucD, tsh, vat and cva/cv) using PCR methods. The E. coli strains were also screened phenotypically for the production of extended-spectrum β-lactamase (ESBL) and the susceptibility of 48 potential ExPEC isolates for nalidixic acid and ciprofloxacin was tested.Results
E. coli was isolated from 207 (94.5%) of 219 poultry meat products. The most common phylogenetic groups were D (50.7%), A (37.7%), and B2 (7.7%). Based on virulence factor gene PCR, 23.2% of the strains were classified as ExPEC. Two ExPEC strains (1%) belonged to [O1] B2 svg+ (specific for virulent subgroup) group, which has been implicated in multiple forms of ExPEC disease. None of the ExPEC strains was resistant to ciprofloxacin or cephalosporins. One isolate (2.1%) showed resistance to nalidixic acid.Conclusions
Potential ExPEC bacteria were found in 22% of marinated and non-marinated poultry meat products on the Finnish retail market and 0.9% were contaminated with E. coli [O1] B2 svg+ group. Marinades did not have an effect on the survival of ExPEC as strains from marinated and non-marinated meat products were equally often classified as ExPEC. Poultry meat products on the Finnish retail market may have zoonotic potential. 相似文献14.
Tan C Tang X Zhang X Ding Y Zhao Z Wu B Cai X Liu Z He Q Chen H 《Veterinary journal (London, England : 1997)》2012,192(3):483-488
Extraintestinal pathogenic Escherichia coli (ExPEC) isolates were detected in 315/3127 (10.1%) diseased pigs from 19 provinces of China; the frequency of isolation increased from 3.1% in 2004 to 14.6% in 2007. All isolates were characterised for O serogroups, haemolysis, phenotypic and genotypic antimicrobial resistance, virulence genes and pathogenicity. The most prevalent serogroups were O161, O8, O11, O138, O101 and O26; 83/315 (26.3%) isolates were haemolytic. Forty percent of isolates in phylogenetic groups B2 and D were highly virulent porcine ExPEC strains. Thirty-three putative extraintestinal virulence factor genes that are normally associated with human and/or avian ExPEC strains were widely present in porcine isolates. These results indicate that ExPEC are prevalent in pigs in China and represent a potential public health threat. 相似文献
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本研究旨在评价猪β防御素2（porcine beta defensin 2，PBD-2）在体内外对猪源肠外致病性大肠杆菌（ExPEC）的抗菌效果，为评估PBD-2在抗生素替代品中的应用前景提供参考。首先，在体外检测不同浓度PBD-2对猪源ExPEC PCN033的杀菌活性。随后，选取5周龄，体重在18~22 g之间的雌性昆明小鼠，检测PBD-2处理组和PBS对照组小鼠（n ≥ 5）感染不同剂量的ExPEC PCN033后的存活率，脑、脾脏、肺脏组织和血液中的载菌量、炎性细胞因子白细胞介素-6（IL-6）、IL-12、IL-1β和肿瘤坏死因子-α（TNF-α）的水平及脑、脾脏、肺脏组织的病理变化程度。结果表明，PBD-2在25 μg/mL时即可在体外极显著抑制猪源ExPEC PCN033的生长（P<0.01），且抑制作用随PBD-2的浓度升高而增强。在体内，与PBS对照组相比，PBD-2处理有效降低了小鼠感染不同剂量ExPEC PCN033后的死亡率。提高PBD-2的治疗剂量对降低小鼠死亡率的效果更加明显。腹腔注射和肌内注射的方式在PBD-2降低小鼠死亡率的效果方面优于口服途径。PBD-2治疗在降低小鼠死亡率的效果方面略低于氯霉素治疗。同时，PBD-2治疗极显著降低了小鼠感染ExPEC PCN033 21 h后的脑、脾脏、肺脏组织和血液中的细菌载量（P<0.01），降低了血液中的IL-6、IL-12和IL-1β的含量（P<0.01），减轻了脑、脾脏和肺脏组织的病变程度。上述结果说明PBD-2在体外具有良好的抗猪源ExPEC的活性，同时在小鼠体内对猪源ExPEC感染具有治疗作用，表明PBD-2具有开发成为治疗性药物或者抗生素替代品的潜力。 相似文献
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Platell JL Cobbold RN Johnson JR Clabots CR Trott DJ 《Comparative immunology, microbiology and infectious diseases》2012,35(4):319-324
Antimicrobial-resistant extraintestinal pathogenic Escherichia coli (ExPEC) impact both human and veterinary medicine. One ExPEC clonal group that has become increasingly multidrug-resistant is serotype O15:K52:H1. Accordingly, we sought O15:K52:H1 strains among fluoroquinolone-resistant (FQ(r)) E. coli clinical isolates from humans (n=582) and dogs (n=120) in Australia. The phylogenetic group D isolates (267/702; 38%) were screened for O15:K52:H1-specific single-nucleotide polymorphisms (SNPs) in fumC and the O15 rfb variant. The 34 so-identified O15:K52:H1 isolates (33 human, 1 canine) underwent antimicrobial susceptibility profiling, virulence genotyping, and macrorestriction profiling. Although susceptibility profiles varied, the 34 isolates were closely related by pulsed-field gel electrophoresis and exhibited typical O15:K52:H1-associated virulence profiles (complete pap operon, F16 papA allele, papG allele II, iha, fimH, sat, fyuA, iutA, kpsMII, ompT). The canine isolate closely resembled human isolates. Thus, O15:K52:H1 strains contribute to the FQ(r) ExPEC population in Australia and may potentially be transferred between humans and dogs. 相似文献
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To investigate the cause of piglets diarrhea, and the distribution of the serotype and virulence factors of swine Escherichia coli in Beijing, 400 diarrhea samples were collected. TSA serum agar culture method was used to isolate Escherichia coli, serotype identification test and virulence factor genes test were used to verify the presence of O-antigen. 64 strains of E.coli were isolated from 400 diarrhea samples, among which 42 strains of E.coli were classified as 8 serotypes:O101(18.7%),O64(12.5%),O8(10.9%),O20(10.9%),O45(4.7%),O149(4.7%),O2(1.6%) and O89(1.6%), and the major virulence factors were STa, Stx2e, astA and eaeA. There were 8 mainly serotypes that caused piglets diarrhea in Beijing area, among which O101 serotype accounted for the highest proportion. The major virulence factors were astA and eaeA, accounted for more than 50% of all strains, STa and Stx2e accounted for more than 30% of all strains. These data would provide effective data to support the prevention and control of piglet diarrhea in Beijing. 相似文献
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本试验旨在调查北京地区仔猪腹泻的原因及猪源大肠杆菌血清型、毒力因子的分布情况。收集北京京郊地区仔猪腹泻样本400份,应用含2%血清的TSA培养基分离大肠杆菌,通过血清型鉴定试验和毒力因子检测验证O抗原。结果显示,400份样本中分离到64株大肠杆菌,定型42株。其主要为O101型（18.7%）、O64型（12.5%）、O8型（10.9%）、O20型（10.9%）、O45型（4.7%）、O149型（4.7%）、O2型（1.6%）、O89型（1.6%）8种血清型,其携带的毒力因子为STa、Stx2e、astA和eaeA等。结果表明,引起京郊仔猪腹泻的大肠杆菌主要有8个血清型,其中O101型发病比例最高。其携带的毒力因子主要为astA和eaeA,占全部菌株的50%以上,STa和Stx2e因子占全部菌株的30%以上。本试验结果将为今后京郊地区仔猪腹泻病的防控提供有效的数据支持。 相似文献
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Avian pathogenic Escherichia coli(APEC) is an important pathogen that causes localized and systemic infection in avian species of all ages.It is also an important reservoir or source of virulence genes of human extraintestinal pathogenic Escherichia coli (ExPEC).In order to understand deeply the infection progresses,pathogenesis,host immune responses and genetic resistance mechanism of APEC,and evaluate the efficacy of drugs and vaccines,several experimental infection models were established to evaluate the virulence of APEC through different approaches.According to the different systems involved,it can be divided into respiratory system,vascular system,musculoskeletal system,dermatological system,reproductive system,gastrointestinal system and chicken embryo system.In addition,there are infection experiments in mice and rats,tissue culture cells and explants infection experiments in vitro.The author highlights the establishment,pathogenesis,host responses and application of the different APEC experimental infection models. 相似文献