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固有免疫细胞在外源物质刺激后向细胞胞外环境释放由染色质DNA和多种胞内颗粒蛋白组成的纤维样网状物质，称为胞外诱捕网（extracellular traps，ETs）。ETs是一种新型的宿主防御机制，能够捕获或杀灭病原菌，有效控制病原菌的扩散，从而使机体免受感染。大肠杆菌、沙门菌等食源性人兽共患病病原体引发的疾病是全球广泛关注的公共卫生问题。本文就食源性病原菌激发固有免疫细胞ETs的形成、ETs的生物学活性以及细菌部分蛋白对ETs形成的影响等研究进展进行综述，以期为食源性疾病的防控提供相关理论参考。 相似文献
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Murphy CP Reid-Smith RJ Boerlin P Weese JS Prescott JF Janecko N Hassard L McEwen SA 《The Canadian veterinary journal. La revue veterinaire canadienne》2010,51(9):963-972
Hospital-based infection control in veterinary medicine is emerging and the role of the environment in hospital-acquired infections (HAI) in veterinary hospitals is largely unknown. This study was initiated to determine the recovery of Escherichia coli and selected veterinary and zoonotic pathogens from the environments of 101 community veterinary hospitals. The proportion of hospitals with positive environmental swabs were: E. coli--92%, Clostridium difficile--58%, methicillin-resistant Staphylococcus aureus (MRSA)--9%, CMY-2 producing E. coli--9%, methicillin-resistant Staphylococcus pseudintermedius--7%, and Salmonella--2%. Vancomycin-resistant Enterococcus spp., canine parvovirus, and feline calicivirus were not isolated. Prevalence of antimicrobial resistance in E. coli isolates was low. Important potential veterinary and human pathogens were recovered including Canadian epidemic strains MRSA-2 and MRSA-5, and C. difficile ribotype 027. There is an environmental reservoir of pathogens in veterinary hospitals; therefore, additional studies are required to characterize risk factors associated with HAI in companion animals, including the role of the environment. 相似文献
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A Mayr 《Berliner und Münchener tier?rztliche Wochenschrift》1992,105(7):217-219
During pregnancy infections can entail disorders in many different ways. Damage through direct transmission of pathogens to the fetus occurs in the first place. The organisms are transmitted transovarially, diaplacentally, via endometrium, before or after implantation, via amnion or by the semen when ascending through the infectious environment. Embryo transfer is a new way of transmission. The respective infective microorganisms either directly colonize in the embryo with the well known consequences (fetotrope pathogens) or they colonize the placenta thus indirectly leading to damages to the embryo (placentotrope pathogens). During the process various overlappings are possible. A second large group of disorders in pregnancy is caused by effects of infections of the mother without pathogens being transmitted to the embryo or the placenta. These diseases are postinfectious allergies, immune complex diseases, damages through microbial toxins or mediators and various other forms of infectious processes found with the mother. The third group of disorders in pregnancy is the result of complications caused by vaccinations of the mother during or shortly before pregnancy: postvaccinal allergies, diseases through vaccinal germs and different other postvaccinal damages or stress because of vaccination. 相似文献
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Calf diarrhea is a commonly reported disease in young animals, and still a major cause of productivity and economic loss to cattle producers worldwide. In the report of the 2007 National Animal Health Monitoring System for U.S. dairy, half of the deaths among unweaned calves was attributed to diarrhea. Multiple pathogens are known or postulated to cause or contribute to calf diarrhea development. Other factors including both the environment and management practices influence disease severity or outcomes. The multifactorial nature of calf diarrhea makes this disease hard to control effectively in modern cow-calf operations. The purpose of this review is to provide a better understanding of a) the ecology and pathogenesis of well-known and potential bovine enteric pathogens implicated in calf diarrhea, b) describe diagnostic tests used to detect various enteric pathogens along with their pros and cons, and c) propose improved intervention strategies for treating calf diarrhea. 相似文献
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George M Barrington John M Gay James F Evermann 《Veterinary Clinics of North America: Food Animal Practice》2002,18(1):7-34
Infectious diarrhea is an important cause of neonatal calf morbidity and mortality that results in significant economic losses in the beef and dairy industries. Although numerous risk factors related to the occurrence of neonatal diarrhea have been identified, they can all be categorized into those that are related to the calf, the pathogens involved, or the environment of the calf. The immune status of calves, specifically the level of passively acquired immunity through colostrum, is the major risk factor related to the calf and the occurrence of diarrhea. Although numerous pathogens have been implicated in the occurrence of neonatal diarrhea, only a relatively limited number are commonly involved. Most should be viewed as secondary opportunists rather than primary pathogens, because none are extraordinarily virulent, and with the exception of Salmonella spp., most are present within the gastrointestinal tract of many healthy, mature cattle. Important risk factors related to pathogens involved in neonatal calf diarrhea involve the size of the inoculum and the occurrence of multiple infections. Finally, when considering the environment and housing conditions in which beef and dairy calves may reside, it is clear that tremendous variations exist. Despite these variations, the risk factors associated with the environment of the calf are also those that are the most amenable to the implementation of general environmental control and monitoring strategies as well as specific biosecurity measures. 相似文献
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Gyles CL 《Veterinary microbiology》2011,153(1-2):2-12
Research on pathogenesis of bacterial diseases involves exploration of the intricate and complex interactions among pathogen, host, and environment. Host-parasite-environment interactions that were relatively simple were the first to be understood. They include intoxications in which ingestion of a powerful bacterial toxin was sufficient to cause disease. In more complex cases bacteria occupy a variety of niches in the host and attack at an opportune time. Some bacterial pathogens have a brief encounter with the host; others are long-term guests. This variety of relationships involves a wide range of strategies for survival and transmission of bacterial pathogens. Molecular genetics, genomics and proteomics have facilitated understanding of the pathogens and hosts. Massive information often results from such studies and determining the relevance of the data is frequently a challenge. In vitro studies often attempt to simulate one or two critical aspects of the environment, such as temperature, pH, and iron concentration, that may provide clues as to what goes on in the host. These studies sometimes identify critical bacterial virulence factors but regulation of bacterial virulence and host response is complex and often not well understood. Pathogenesis is a process of continuous change in which timing and degree of gene expression are critical and are highly regulated by the environment. It is impossible to get the full picture without the use of natural or experimental infections, although experimental infections involve ethical and economic considerations which may act as a deterrent. 相似文献
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Zoonotic aspects of Mycobacterium bovis and Mycobacterium avium-intracellulare complex (MAC) 总被引：4，自引：0，他引：4
Pathogens that are transmitted between the environment, wildlife, livestock and humans represent major challenges for the protection of human and domestic animal health, the economic sustainability of agriculture, and the conservation of wildlife. Among such pathogens, the genus Mycobacterium is well represented by M. bovis, the etiological agent of bovine tuberculosis, M. avium ssp. paratuberculosis (Map) the etiological agent of Johne disease, M. avium ssp. avium (Maa) and in a few common cases by other emergent environmental mycobacteria. Epidemiologic surveys performed in Europe, North America and New Zealand have demonstrated the existence and importance of environmental and wildlife reservoirs of mycobacterial infections that limit the attempts of disease control programmes. The aim of this review is to examine the zoonotic aspects of mycobacteria transmitted from the environment and wildlife. This work is focused on the species of two main groups of mycobacteria classified as important pathogens for humans and animals: first, M. bovis, the causative agent of bovine tuberculosis, which belongs to the M. tuberculosis complex and has a broad host range including wildlife, captive wildlife, domestic livestock, non-human primates and humans; the second group examined, is the M. avium-intracellulare complex (MAC) which includes M. avium ssp. avium causing major health problems in AIDS patients and M. avium ssp. paratuberculosis the etiological agent of Johne disease in cattle and identified in patients with Crohn disease. MAC agents, in addition to a broad host range, are environmental mycobacteria found in numerous biotopes including the soil, water, aerosols, protozoa, deep litter and fresh tropical vegetation. This review examines the possible reservoirs of these pathogens in the environment and in wildlife, their role as sources of infection in humans and animals and their health impact on humans. The possibilities of control and management programmes for these mycobacterial infections are examined with regards to the importance of their natural reservoirs. 相似文献
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Industrial fish production exposes fish to potentially stressful conditions, which in turn may induce infections by opportunistic pathogens. Probiotics appear to be a promising way to prevent opportunistic infections in aquaculture. In this study, we tested the inhibitory potential of endogenous bacterial communities found in the mucus of brook charr (Salvelinus fontinalis) against two major pathogens Flavobacterium columnare and Flavobacterium psychrophilum. Nine bacterial strains were isolated from brook charr skin mucus and tested for potential antagonistic activity. Results from both agar diffusion assays and broth co-culture assays showed the presence of antagonism. We identified seven bacterial strains, collected from unstressed fish, which exerted strong antagonism against F. psychrophilum and/or F. columnare. These strains were mixed and used to treat columnaris disease in an in vivo experiment in which four distinct fish families were tested. This treatment resulted in a decrease of mortality (54-86%) across fish families indicating that candidates from the host microbiota are potentially suitable for probiotic development. This would allow for the efficient (ability to adhere and colonize the host mucus) and durable management (antagonistic effect against pathogens which would be harmless for the host and safe for its environment) of opportunistic diseases in aquaculture. 相似文献
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Lauzon HL Gudmundsdottir S Pedersen MH Budde BB Gudmundsdottir BK 《Veterinary microbiology》2008,132(3-4):328-339
Survival problems are encountered at early stages of intensive fish rearing and antibiotics are widely used to remedy the situation. Probiotics may provide a potential alternative method to protect larvae from opportunistic and pathogenic bacteria and promote a balanced environment. This study was designed to search for new probiotics to target this critical period in cod rearing. Potential probionts were selected from the natural microbiota of cod aquacultural environment. The selection was based on several criteria: pathogen inhibition potential, growth characteristics, strain identification, metabolite production and adhesion to fish cell lines. Our study demonstrated that 14% of screened bacteria (n=188) had antagonistic properties towards fish pathogens. The majority of these isolates were Gram-positive (81%), belonging to Firmicutes (69.2%) and Actinobacteria (11.5%) phyla based on 16S rRNA gene sequencing. Only 6 (3.2%) of 188 isolates could inhibit all three pathogens tested: Vibrio anguillarum, Aeromonas salmonicida subsp. achromogenes and Vibrio salmonicida. Differences observed in activity intensity and spectrum among inhibitory isolates emphasise the need to develop probiotic mixtures for efficient prophylactic methods. Comparison of growth behaviour of inhibitory isolates and pathogens at cod rearing temperatures, metabolite production and adhesion capacity were considered for final probiont selection. Four promising isolates that could be used as a mixed supplement to rearing water were identified as putative probiotic bacteria. This study emphasises the importance and potential of lactic acid bacteria in aquaculture. 相似文献
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病原微生物荚膜多糖的生物学功能 总被引：2，自引：1，他引：1
荚膜多糖（capsular polysaccharide，CPS）是一种广泛存在于细菌、支原体、部分真菌等菌体表面的碳水化合物。同时，荚膜多糖有助于菌体抵抗干燥和低温等不利环境，并通过在菌体表面形成物理屏障阻碍宿主补体的杀伤与吞噬作用。在长期多种应激-压力环境下，病原菌已进化出多种免疫逃避机制并促进宿主感染；在非病原微生物中，荚膜多糖可正向调节宿主免疫作用，并拮抗机体免疫因子，保护宿主免受病原菌引起的炎症性疾病。本文将结合本团队的相关研究工作，对荚膜多糖的结构、合成调控机制、生物学功能、免疫逃避机制和致病机制，特别是荚膜多糖正向调节宿主免疫系统及其应用潜力等方面作一综述，为病原菌致病机制的研究和疫病的有效防控提供参考依据。 相似文献
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A J Husband 《Veterinary immunology and immunopathology》1987,17(1-4):357-365
All mammalian species have developed specialized defence mechanisms at the interface between mucosal surfaces and the environment and this system operates independently of the systemic immune system. Attachment of organisms to the mucosal epithelium is a primary prerequisite for infection and is an important virulence determinant for pathogens of these sites. The mucosal immune defences are thus characterized by production of IgA antibodies, the principal mode of action of which is to inhibit the adherence of pathogens to the mucosal epithelium. This introduction to the symposium on mucosal immunity will attempt to underline the role of local immunity in the intestine in providing local defence at that site, in addition to providing cellular molecular effectors for other mucosal sites. 相似文献
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Roberta M Dwyer 《Veterinary Clinics of North America: Equine Practice》2004,20(3):531-542
Cleaning and disinfection are essential to the environmental control of infectious diseases of all animals. By understanding the types of pathogens, environment, and disinfection process, success can be attained in effectively stopping disease outbreaks. 相似文献
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绵羊是省市乡村少数名族生存的基础和发家致富的希望,承载着众多边疆少数民族的稳定性和重大使命。由于今年大西北地区气候寒冷雨水较多,沙尘暴频繁,气候环境恶劣,若饲养管理不到位,病菌在污染的环境中大量存在,接触病菌的机率较大,绵羊腐蹄病直接影响羊的生产性能和繁殖性能,对牧民和养殖户造成巨大的经济损失,结合当地羊发病原因和临床症状实践研究分析从药上对症治疗以及今后的预防措施,供广大牧民和养殖企业参考。 相似文献
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Review on the effects of potential prebiotics on controlling intestinal enteropathogens Salmonella and Escherichia coli in pig production 
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下载免费PDF全文 T. H. T. Tran N. Everaert J. Bindelle 《Journal of animal physiology and animal nutrition》2018,102(1):17-32
Salmonella enterica serotypes (Salmonella sp.) are the second cause of bacterial foodborne zoonoses in humans after campylobacteriosis. Pork is the third most important cause for outbreak‐associated salmonellosis, and colibacillosis is the most important disease in piglets and swine. Attachment to host cells, translocation of effector proteins into host cells, invasion and replication in tissues are the vital virulence steps of these pathogens that help them to thrive in the intestinal environment and invade tissues. Feed contamination is an important source for Salmonella infection in pig production. Many on‐farm feeding strategies intervene to avoid the introduction of pathogens onto the farm by contaminated feeds or to reduce infection pressure when pathogens are present. Among the latter, prebiotics could be effective at protecting against these enteric bacterial pathogens. Nowadays, a wide range of molecules can potentially serve as prebiotics. Here, we summarize the prevalence of Salmonella sp. and Escherichia coli in pigs, understanding of the mechanisms by which pathogens can cause disease, the feed related to pathogen contamination in pigs and detail the mechanisms on which prebiotics are likely to act in order to fulfil their protective action against these pathogens in pig production. Many different mechanisms involve the inhibition of Salmonella and E. coli by prebiotics such as coating the host surface, modulation of intestinal ecology, downregulating the expression of adhesin factors or virulence genes, reinforcing the host immune system. 相似文献
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生姜黄酮粗提液对部分家蚕病原细菌的抑杀效果试验 总被引：2，自引：1，他引：1
采用天然植物活性成分防治家蚕细菌病不仅具有安全、环保的特点,而且还能解决病原菌的耐药性问题。生姜中富含的黄酮类物质具有多种生物活性及药理作用。采用滤纸片法和打孔法研究了生姜黄酮粗提液对家蚕病原细菌卒倒杆菌(Bacillus thuringiensis)和青头败血病菌(Aeromonas)的体外抑菌效果,结果表明7.46、3.73、2.49、1.49和1.07 mg/mL生姜黄酮粗提液对2种家蚕病原细菌均有一定程度的抑菌效果,且对革兰阴性或阳性菌的抑菌效果没有明显差异。给感染卒倒杆菌的家蚕添食1.49 mg/mL和1.07 mg/mL生姜黄酮粗提液均具有一定的治疗作用,且效果略好于0.1 mg/mL蚕用盐酸诺氟沙星。此外,生姜黄酮粗提液用于蚕病防治对家蚕的生长发育无不良影响。 相似文献
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Bailey M Haverson K Inman C Harris C Jones P Corfield G Miller B Stokes C 《Veterinary immunology and immunopathology》2005,108(1-2):189-198
The mucosal immune system expresses active responses against pathogens and also tolerance against harmless food and commensal bacterial antigens. The mechanisms that determine which of these outcomes occur after recognition of antigens by T-cells are not clear. One possibility is that it is determined by the initial interaction between a dendritic and a na?ve T-cell in organised lymphoid tissue. However, such organised structures are, evolutionarily, quite recent and the original immune system must have made appropriate responses in more diffuse immunological architecture; a second possibility is that the critical interaction is between primed T-cells and their environment, in the lamina propria of the intestine. The mucosal immune system of neonates is poorly developed and inefficient at expressing appropriate immune responses. Development is influenced by a range of environmental factors including maternally derived antigen or antibody and commensal flora and pathogens. The intestine is a complex immunological structure in which the immune system and the macro- and microenvironment interact. 相似文献
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Shiga toxin-producing Escherichia coli (STEC) are one of the most important emergent foodborne pathogens. STEC are common as colonizers in the intestine of healthy cattle and are spread into the environment by fecal shedding or following the surface application of farm effluent on soil. The bacteria can be transmitted to humans through food, such as inadequately cooked ground beef or unpasteurized milk. During the last decade, a wide variety of environmentally related exposures have emerged as new routes of transmission. Major outbreaks due to the consumption of raw fruits and vegetables or accidental ingestion of soil or water contaminated by STEC have been increasingly reported. STEC survival in cattle effluents, soil, plants and water is discussed in the light of new knowledge regarding both biotic and abiotic factors which may affect their survival or enhance their dissemination in the environment. The ability to persist in cattle production environments contributes to the contamination and recontamination of cattle, as well as for human infection. Consequently, effective control strategies must be considered on cattle farms, in order to limit entry of STEC cells into the environment. 相似文献