Campylobacter in poultry: filling an ecological niche

Epidemiological studies indicate that Campylobacter species may be responsible for the majority of cases of sporadic gastroenteritis in humans. These studies also suggest that poultry may be one of the most common sources of the bacteria for humans. Campylobacter and related genera in the family Campylobacteraceae are oral and intestinal commensals of vertebrates and some nonvertebrates, a characteristic that complicates rational approaches to controlling Campylobacter contamination of poultry. This review will discuss the phylogeny, genomics, and physiology of campylobacters with the intention of revealing how these organisms have evolved to fill their intestinal ecological niche in poultry and how their physiology must be understood in order to enact effective control strategies.     

耐药弯曲杆菌适应性代价研究进展

弯曲杆菌在产生耐药性之后,其生存力、稳定性、毒力可能会发生一系列的变化,即适应性发生改变。耐药菌的适应性若增强,则能在机体内占据主导优势,增加耐药菌在宿主和环境中传播的风险;若耐药菌获得了适应性代价(即适应性和生命力的下降),在各方面不敌敏感菌,则会在竞争中逐渐被清除。部分产生适应性代价的细菌通过自身的代偿突变恢复其适应性,可能会成为优势菌群,加大治疗难度。故耐药菌与敏感菌的竞争力决定了其在宿主体内或环境中的存在和繁殖能力,也决定了宿主疾病的发展与转归。弯曲杆菌作为一种引起临床多种动物包括人类患病的致病菌,其耐药性引起了人们的关注,其适应性分析更是人们研究的热点。本文对近年来耐药弯曲杆菌的适应性进行了综述,旨在为控制耐药弯曲杆菌的扩散转移和耐药性管理决策提供理论依据和参考。     

空肠弯曲杆菌对喹诺酮类药物产生耐药性的作用机制和发展趋势

从 2 0世纪 70年代起 ,空肠弯曲杆菌 (Campy-lobacter jejuni)在全世界就被普遍认为是肠道感染的主要原因。主要是通过被污染的食物造成人类的感染。大部分空肠弯曲杆菌肠炎的病例并不需要抗生素治疗 ,因为大多数空肠弯曲杆菌肠炎是自限性感染 ,临床症状较轻。但是严重的感染和被拖延了的肠炎病例、败血症都需要抗生素治疗。喹诺酮类药物是治疗空肠弯曲杆菌肠炎中使用最普遍的药。随着喹诺酮类抗性菌种造成感染数量的增多 ,人类感染空肠弯曲杆菌病例也越来越多。人们在肉用动物生产中使用了大量的喹诺酮类药物 ,使喹诺酮类药物在食物链中出…     

岩溶地区发展生态畜牧业的潜力、问题和支撑体系

中国工程院关注岩溶地区生态修复和扶贫开发,部署了西南草地畜牧业咨询项目.本文是该项目专题调研组在任继周院士带领下赴渝、桂、粤、黔、滇、湘6省的考察报告.调研组发现岩溶地区存在发展生态畜牧业的巨大潜力,发展生态畜牧业可解决生态修复和脱贫致富方面的难题,还分析了岩溶地区生态畜牧业发展存在的问题和应建立的支撑体系.     

Zoonotic hepatitis E: animal reservoirs and emerging risks

Hepatitis E virus (HEV) is responsible for enterically-transmitted acute hepatitis in humans with two distinct epidemiological patterns. In endemic regions, large waterborne epidemics with thousands of people affected have been observed, and, in contrast, in non-endemic regions, sporadic cases have been described. Although contaminated water has been well documented as the source of infection in endemic regions, the modes of transmission in non-endemic regions are much less known. HEV is a single-strand, positive-sense RNA virus which is classified in the Hepeviridae family with at least four known main genotypes (1–4) of mammalian HEV and one avian HEV. HEV is unique among the known hepatitis viruses, in which it has an animal reservoir. In contrast to humans, swine and other mammalian animal species infected by HEV generally remain asymptomatic, whereas chickens infected by avian HEV may develop a disease known as Hepatitis-Splenomegaly syndrome. HEV genotypes 1 and 2 are found exclusively in humans while genotypes 3 and 4 are found both in humans and other mammals. Several lines of evidence indicate that, in some cases involving HEV genotypes 3 and 4, animal to human transmissions occur. Furthermore, individuals with direct contact with animals are at higher risk of HEV infection. Cross-species infections with HEV genotypes 3 and 4 have been demonstrated experimentally. However, not all sources of human infections have been identified thus far and in many cases, the origin of HEV infection in humans remains unknown.     

改善畜禽饲养环境,推动生态畜牧业发展

近几年来,随着我国畜牧业的快速发展,畜产品数量的逐年攀升,畜禽疫病却不断增加,一些动物源性疫病如非典、禽流感、甲型H1N1流感等都逐渐成为危害人体健康的重要疾病;而另一方面,由于疾病、药残和污染等问题的存在,使我国猪肉安全性及肉品质得不到根本保证,因而制约了我国养猪业健康、持续、稳定的发展。     

山东省鸡源空肠弯曲菌喹诺酮类药物耐药机制研究

通过对采集于山东省肉鸡屠宰场的202株空肠弯曲菌进行喹诺酮类耐药分子机制的研究,包括7种可以移动耐药基因筛查,喹诺酮耐药决定区(QRDR)突变检测和parC的筛查,确定了我国山东省鸡源空肠弯曲菌对喹诺酮类药物的耐药表型主要为gyrA中QRDR C-257-T突变所造成.并发现在空弯中存在于gyrA和gyrB基因上的部分沉默突变有着地域流行性特点.这些观察结果为解释我国食品动物源空肠弯曲菌耐药性现状,防控耐药空肠弯曲菌传播和流行提供基础数据.     

云南省岩溶地区生态修复与草地畜牧业发展的思考

根据岩溶的形成机理及国内外治理途径、研究方向,在全面分析云南岩溶地区地形地貌的基本特征、社会经济状况的基础上, 通过国家重大草业项目"云南省巧家县岩溶地区草地治理试点工程"的实施和取得的初步成果,总结20多年来云南省岩溶地区生态修复与草地畜牧业发展的实践和经验,提出岩溶地区综合治理最主要的措施是发展草地畜牧业;确立了云南岩溶地区生态修复和发展草地畜牧业的主要模式,即滇东、滇北采用"退、改、复"草地生态修复模式,建立以肉牛、肉羊、绵羊为主的草地畜牧业产业带;滇中、滇西采用"封、围、建"草地生态修复模式,建立以肉牛、奶牛为主的草地畜牧业产业带;滇南采用"除、替、引"草地生态修复模式,建立以肉牛、肉羊、奶水牛为主的草地畜牧业产业带.针对存在的困难和问题,建议国家要明确岩溶地区草地生态修复工程,优化创新实用技术等对策措施,全面揭示岩溶地区生态环境问题的本质,实现生态、生活的双改善.     

弯曲菌耐药性的研究进展

弯曲菌耐药性已经成为全球关注的重点,尤其是对氟喹诺酮类和大环内酯类的耐药性,在人和动物表现更为严重。本文对人和动物弯曲菌临床耐药性的状况、生物杀菌剂耐药性和环境因素在弯曲菌耐药性的获得与传播中的作用等方面进行综述。     

强化规模场污染治理 促进畜牧业生态化发展

本文分析了江苏省规模场污染治理现状,结合省情,提出了污染综合治理与生态化利用的工作思路及对策建议。     

大力推进青海草地生态畜牧业建设

为探索青海省草地畜牧业的可持续发展之路,在青海省省委、省政府的高度重视和大力支持下,从2008年起,青海省农牧厅在牧区选择7个村,以村为单它开展生态畜牧业建设,经过两年试点,在实践中初步探索出了科学转变青海省草地畜牧业生产经营及发展方式的新模式和新路子.     

Campylobacter jejuni infection in the ferret: an animal model of human campylobacteriosis

Campylobacter infection in weanling ferrets (Mustela putorius furo) was studied as an animal model for enteric campylobacteriosis in persons. The screening of fecal cultures on selective campylobacter media showed that Campylobacter jejuni/coli was not present in the normal enteric flora. Intragastric feeding of a mixture of cat feed and 2.5 X 10(8) C jejuni isolated from ferrets with naturally occurring proliferative colitis was accomplished. All ferrets (n = 8) became infected on 3 days after they were inoculated, and at 5 to 7 days, they had bile-tinged, liquid feces with excessive mucus and blood. Ferrets gradually recovered from the diarrhea, and feces were normal 10 to 14 days after inoculation was done. Feces contained C jejuni at 14, 23, 28, 39, 46, 60, 91, 101, 109 and 144 days. In the second experiment, weanling ferrets initially were treated with 10% sodium bicarbonate, and 1 X 10(10) C jejuni organisms were administered in the cat feed. Diarrhea with fecal leukocytes and occult blood with occasional mucus appeared in almost all of the 21 ferrets from days 4 through 7. Campylobacter jejuni was isolated from the blood of 11 ferrets between 3 hours and 14 days after they were inoculated. Campylobacter jejuni bactericidal antibodies were present in serum samples at 14 days, with titers of 1:16 to 1:32. Intestinal lesions including cellular infiltration with mononuclear and polymorphonuclear leukocytes were in the lamina propria of the pyloric mucosa and small intestine of infected and control ferrets. The colon of 3 infected ferrets had small focal infiltrates of neutrophils on the lamina propria; one ferret had perivascular cuffing.(ABSTRACT TRUNCATED AT 250 WORDS)     

论甘南高原生态建设与可持续发展战略

简述了甘南高原区的自然地理特点,分析了甘南高原区的主要生态环境问题及其成因;指出甘南高原的生态地位十分重要,其生态环境严重恶化的状况已直接威胁到本区域乃至黄河、长江流域社会经济的可持续发展,大力开展生态保护与生态建设已刻不容缓,提出了甘南高原区生态保护、生态建设与可持续发展的对策建议。     

滕州生态畜牧业发展趋势

畜牧业是山东省滕州市农业生产中的重要支柱性产业.长期以来,伴随着畜牧业的快速发展,畜禽养殖粪污的有效治理成为制约滕州市畜牧业向"优质、高效、绿色"发展的影响因素.随着国家环保政策的收紧,畜牧业发展亟待在追求增量的同时寻找出一条生态、循环的新路径.畜牧业生态化发展成为畜禽养殖可持续发展的趋势.笔者对滕州市畜牧业生态发展现...     

Genotypes and antibiotic resistance of Campylobacter coli in fattening pigs

Campylobacter coli is a food-borne zoonotic pathogen causing human gastroenteritis worldwide. The organism is a commensal in the intestine of many food production animals including fattening pigs. The role of the pig as a potential reservoir for C. coli affecting human either directly or via poultry has hardly been investigated and genetic characterization of porcine strains is needed to address this question. For this aim multilocus sequence typing (MLST) and flaB typing was applied to 256 C. coli isolates from faeces of fattening pig collected during 2009 at different slaughterhouses in Switzerland. In addition genotypic resistances towards macrolides and quinolones based on point mutations in the 23S rRNA and gyrA genes, respectively, were determined. Of the 67 sequence types (STs) obtained by MLST, 37 were found for the first time. flaB typing revealed 46 different types with 14 of them being novel and was useful to further differentiate strains with an identical ST. Quinolone resistance was detected in 33.6% and macrolide resistance was found in 10.6% of isolates. Comparison with 99 C. coli pig isolates from 2001 revealed a significant decrease in antibiotic resistance towards both groups of antibiotics and there was high overlap between genotypes of 2001 and 2009. Little overlap of porcine genotypes was found with 97 C. coli isolates from poultry collected 2008, however, macrolide resistance was significantly higher in pig isolates. In conclusion, C. coli from Swiss pig are heterogeneous containing many novel STs, findings that could reflect the partitioned Swiss pig production with almost no international breed exchange. The antibiotic resistance echoes the use of corresponding drugs in the Swiss livestock production and indicates the efficacy of restrictive application of antibiotics in order to reduce resistances.     

Antimicrobial resistance in Campylobacter from broilers: association with production type and antimicrobial use

The isolation and antimicrobial resistance of Campylobacter jejuni and Campylobacter coli strains from broilers arriving in French slaughterhouses, were analysed according to production types (i.e. standard, export or free-range) and antimicrobial (i.e. coccidiostats, growth promoters or therapeutic agents) administration in flocks. Prevalence was 56.6% in standard, 51.3% in export and 80.0% in free-range broilers. Three hundred and ninety-three strains were identified. Two-thirds of the strains belonged to the species C. jejuni. The others were C. coli. Antimicrobial susceptibility testing was carried out for ampicillin, nalidixic acid, enrofloxacin, tetracycline, erythromycin and gentamicin according to a dilution method. The percentages of resistant strains were, 23, 25, 17, 57, 0.3 and 0% for C. jejuni and 29, 43, 40, 70, 31 and 0% for C. coli. Statistical analysis revealed significant difference in distribution of C. jejuni and C. coli and antimicrobial resistance according to production type or antimicrobial administration.     

回眸2009:百花齐放,辽宁畜牧业满园春

2009年是辽宁省现代畜牧业推进计划实施的第二年,过去的一年,为应对历史罕见国际金融危机的不利影响,确保畜牧业持续健康发展,辽宁省各地纷纷推出新政策、新举措,着力强化畜牧业在农村经济发展中的主导地位,为实现全省国民经济又好又快发展发挥重要作用。近期,辽宁省畜牧兽医局公布了2009年度辽宁省现代畜牧业推进计划目标责任制考评结果,其中,朝阳市、锦州市、铁岭市及鞍山市动物卫生监督管理局获得先进单位称号,沈阳市、丹东市、大连市及阜新市动物卫生监督管理局荣获突出贡献奖单位称号,为总结宣传先进地区的经验和做法,本刊记者经过多次采访、调研和整理,形成此文,以期能为全省畜牧兽医工作者提供借鉴,同时预祝辽宁省畜牧兽医工作在新的年度再创辉煌。     

加强草原生态环境保护与建设走可持续发展之路

针对呼伦贝尔市草原利用现状和存在问题,提出草原生态保护与建设的发展对策,全面彻底落实草原“双权一制”工作,实行依法治草,积极开展以人工草地建设和治理退化草地为重点,大力加强牧草种子工程建设,大力发展秸秆养畜等技术措施,解决畜草矛盾,保护草原生态,实现经济、生态和社会效益的全面提高,促进畜牧业经济的可持续发展。     

论生态环境与动物医学之间的关系

生态环境(包括人们的生产生活)对动物生命活动及其致病因素的影响十分巨大而深远,而动物的生命活动及其致病因素对生态环境的影响亦直接而明显,两者相互关联、相互作用、互为一个整体。因此研究生态环境与动物医学之间的关系,对控制疫病、保护环境有着重要的现实意义。