禽源空肠弯曲杆菌耐药性与致病性研究

为了解不同环节禽源空肠弯曲杆菌携带状况及其耐药性与致病性,从肉鸡养殖环节和屠宰环节采集600份样品并分离到241株空肠弯曲杆菌,采用微量肉汤稀释法和PCR方法对分离菌株进行耐药性和毒力基因检测.结果显示:分离菌株对环丙沙星、萘啶酸、四环素的耐药情况尤为严重,耐药率分别为97.75％、96.78％、95.18％;养殖环节...     

禽源空肠弯曲杆菌ERIC-PCR分型及毒力因子研究

[目的] 通过对禽源空肠弯曲杆菌分子分型和毒力研究,了解禽源空肠弯曲杆菌在禽肉产品生产过程中的主要传播途径和携带的主要致病因子。[方法] 对从家禽养殖场、屠宰场等采集的720份泄殖腔拭子和禽肉表面拭子样品分离的311株空肠弯曲杆菌进行ERIC-PCR分型和16种毒力因子检测。[结果] 禽源空肠弯曲杆菌的分离率为43.19%;肉鸡生产链中空肠弯曲杆菌沿生产链传播,且有优势菌株型;90%以上分离菌株携带11种毒力基因。[结论] 肉鸡生产链中空肠弯曲杆菌存在水平传播现象,且没有外源性污染;16种毒力基因中,14种毒力基因的携带率均在50%以上。加强禽源空肠弯曲菌的监测是控制空肠弯曲菌的前提,对公共卫生具有重要意义。     

猪源空肠弯曲杆菌的分离及鉴定

为了研究更快、更加准确分离空肠弯曲杆菌的方法,试验同时采用常规生化法对由12份猪盲肠内容物中分离的可疑菌进行检测,得到了6个阳性样品,经特异性PCR检测,2个样品可定性为空肠弯曲杆菌,检测时间为7 d;而对所得菌株直接进行PCR检测,检测结果相同,检测时间为2 d。结果表明:PCR可以快速、特异性地检测空肠弯曲杆菌,与常规生化检测法相比是一种更有效的方法。     

胶东半岛地区鸡源空肠弯曲杆菌毒力基因携带状况调查

为了了解胶东半岛地区鸡源空肠弯曲杆菌的毒力基因携带和流行情况,对胶东半岛不同来源的样品进行本菌的分离鉴定,用PCR法对分离菌株的14种毒力基因进行了检测。结果:胶东半岛地区鸡源空肠弯曲杆菌的平均分离率为45%。14种检测的毒力因子cia B、rac R、dna K、pld A、cdt A、cdt B、cdt C、neu B1、che W、grp E、che Y、fla A、peb1A cad F的检出率分别为96.26%、97.2%、100%、100%、76.64%、99.07%、99.07%、4.67%、99.07%、71.96%、98.13%、100%、99.07%和99.07%。结果表明,胶东半岛地区鸡源空肠弯曲杆菌毒力基因携带率高,不同毒力基因携带率差异大。所以,加强空肠弯曲杆菌毒力基因的监测,对公共卫生安全意义重大。     

空肠弯曲杆菌特异性基因研究综述

空肠弯曲杆菌是人兽共患病原菌,对公共卫生安全和畜牧业,特别是养鸡产业造成一定危害。本文从基因研究的角度出发,对空肠弯曲杆菌的病原生长与流行病学特征、致病机理、致病基因、检测技术、耐药性、防治等方面的研究现状进行了综述,以期对我国空肠弯曲菌肠炎的防治工作提供借鉴。     

禽源空肠弯曲杆菌的分离鉴定及其致病性的初步研究

本研究对广东部分地区不同品种家禽空肠弯曲杆菌的流行状况进行了调查。通过菌落和菌体形态、生化特征、培养特性等生物学特性和多重PCR方法对所分离菌株进行鉴定,结果表明广东地区鸡、鸭和鹅空肠弯曲杆菌的带菌率分别为7.93%、2.46%和4.16%。从分离株中选取10株进行了致病性试验,结果表明禽源空肠弯曲杆菌对雏鸡的主要病理变化是腹泻便血,肝脏出现白色坏死灶,盲肠充血、膨大充满气泡和红色内容物。     

人和禽感染空肠弯曲杆菌产生神经节苷脂抗体

弯曲杆菌病多与急性感染性神经炎相关。空肠弯曲杆菌频繁定居的禽类是弯曲杆菌病的主要食源性载体。在由美国,日本和英国科学家进行的一项联合研究中,一株分离自感染人员的VLA2/18(未定血清型)接种试验鸡,导致了针对GM1的高效价血清抗体。但是,免疫鸡只没有表现如瘫痪或爬行之类的明显的神经症状。在体外脊髓和肌肉细胞共培养的系统中,人和禽血清中的抗GM1的高滴度抗体能强烈阻止自发性肌肉行为倾向。另外,感染空肠弯曲杆菌81116(HS6)和99/419(HS21)或用提纯的GM1,GM2和GM3进行联合免疫都能导致血清中抗神经节苷脂抗体随着阻止自发性…     

空肠弯曲杆菌基因分型方法的研究进展

空肠弯曲杆菌(campylobacter jejuni)是最重要的人类肠道致病菌之一。随着近年来分子生物学及相关技术的迅猛发展,空肠弯曲杆菌基因分型的方法因其分辨力、特异性、分型率、敏感性显著高于传统检测方法而越来越受到人们的重视。作者就空肠弯曲杆菌基因分型方法(RFLP 分型、AFLP 分型、RAPD 分型、PFGE分型、MLST分型)的研究进展作一简要综述。     

空肠弯曲杆菌耐药性及其主要相关基因初步分析

从307份鸡盲肠内容物样品中分离到47株空肠弯曲杆菌,并测定这些空肠弯曲杆菌耐药性,结果显示对喹诺酮类药(环丙沙星)耐药性为31.9%;对氨苄青霉素,克林霉素和红霉素耐药性较高,分别达到85.1%、83.0%和83.0%;而对痢特灵和庆大霉素则较为敏感,敏感度分别为85.1%和74.5%。有89.4%的菌株显示多重耐药性。利用MAMAPCR技术,对获得的47株空肠弯曲杆菌进行检测,结果显示对环丙沙星耐药的15株空肠弯曲杆菌均检测出其在gyrA基因257位发生点突变,30株对喹诺酮药物敏感的菌株均未检出。另外2株对环丙沙星耐药的菌株,有1株检测出点突变。     

Campylobacter jejuni in poultry giblets

A total of 200 poultry giblets, 50 each of chickens, ducks, squab and turkeys, were examined for the presence of Campylobacter jejuni. In chicken giblets, C. jejuni was isolated from gizzards, hearts, livers and spleens with incidences of 28%, 10%, 40% and 16% respectively while 24%, 6%, 36% and 10% of duck gizzards, hearts, livers and spleens were positive for the organism, respectively. C. jejuni was detected in 6% of squab gizzards, in 10% of squab livers but failed to be detected in squab hearts & spleens. In turkey giblets, 16% of gizzards, 4% of hearts, 30% of livers and 8% of spleens were positive for the organism. C. jejuni was more frequently isolated from liver samples than gizzard, spleen and heart samples, each constituting of 29%, 18.5%, 8.5% and 5%, respectively. High incidence of C. jejuni was recorded among chicken giblets (23.5%), followed by duck giblets (19%), then turkey giblets (14.5%) and finally squab giblets (4%).     

Campylobacter jejuni in poultry processed in slaughterhouses

The frequency of occurrence of Campylobacter jejuni germs in dressed poultry was studied for a year. The samples--smears from the body cavities of chickens--were collected during the technological dressing of the chickens; 101 strains of Campylobacter jejuni (i. e. 28.69%) were isolated from the 352 samples analyzed. The occurrence of the germs exhibited a considerable seasonal variance with peak rates in spring and summer. The use of a suitable culture medium, the technique of cultivation and the properties of the isolated strains were studied at the same time. The culture medium (Agar no. 3 IMUNA enriched with supplement C, horse blood and ingredients increasing the aerotolerance of the germs--sodium pyruvate and iron sulphate) used during the investigation was found to be suitable. The technique of cultivation by means of an anaerostat manufactured by the Development Station in Brno, atmosphere regulation (5% CO2) and with a pre-set cultivation temperature (43 degrees C) was found to be suitable for the screening of the Campylobacter jejuni germs.     

PFGE and PCR/RFLP typing of Campylobacter jejuni strains from poultry

1. Pulsed-field gel electrophoresis (PFGE) and PCR-restriction fragment length polymorphisms of the flagellin gene (fla-RFLP) were used to analyse 92 poultry and 110 human strains of Campylobacter jejuni. 2. Among poultry strains, 11 fla-RFLP and 11 PFGE subtypes were found, while human strains could be divided into 23 fla-RFLP and 32 PFGE subtypes. Altogether, 31 fla-RFLP and 32 PFGE subtypes were found. 3. The results show that individual flocks in farms are mostly infected with a single C. jejuni clone, while during subsequent colonisation their genotypes altered. fla-RFLP and PFGE profiles in poultry and humans were identical in less than 6% of cases. The results found so far confirm previous findings that chicken meat does not represent as important a source of campylobacteriosis as was previously believed. 4. The typing of Campylobacter sp. forms the basis for an evaluation of the current state and risk assessment of various Campylobacter sp. sources in relation to humans. Examination of samples with only one method is insufficient for epidemiology studies, because apparently different clones identified with one method could originate from a single clone, which could be proved with the other method.     

鸡源空肠弯曲菌和结肠弯曲菌的临床分离及多重PCR鉴定

弯曲菌(Campylobacter)尤其是空肠弯曲菌(C.jejuni)是重要的人畜共患病病原菌,在人可引起急性胃肠炎,感染严重者伴有心内膜炎、肺炎、败血症、血栓静脉炎、脑膜炎、多发性关节炎以及格林-巴利综合征等疾病[1-3].家禽、家畜、宠物等动物是弯曲菌的常见宿主,因此研究动物源弯曲菌具有重要的公共卫生意义.     

The effect of lactic acid sprays on Campylobacter jejuni inoculated onto poultry carcasses.

Spraying poultry carcasses with 1% lactic acid 10 min after inoculation with Campylobacter jejuni, resulted in a significant reduction in the number of the bacteria after 4 h at 4 degrees C. Some of the inoculated cells, however, survived for at least 144 h. Spraying 10 min after inoculation with 2% lactic acid, totally eliminated all inoculated C. jejuni within 24 h. On the other hand, spraying 24 h after inoculation, with either 1% or 2% lactic acid did not eliminate all the bacteria. Inoculated C. jejuni on poultry carcasses not sprayed with lactic acid, survived at 4 degrees C throughout the sampling period (up to 144 h) and showed little tendency to decrease in number even when the carcasses started to deteriorate. Resident campylobacters on poultry carcasses were significantly reduced by the lactic acid treatment. Frozen and thawed chickens appeared to show a graying of the skins immediately after spraying with lactic acid, slightly stronger with 2% lactic acid, but the colour reverted to normal after 24 h. We were not able to observe any colour change on the fresh broiler chickens after lactic acid treatment. Our results indicated that lactic acid had a significant bactericidal effect on C. jejuni on both naturally and artificially contaminated poultry carcasses. This effect, however, became manifest only several hours after acid treatment.     

Heterogeneity of Campylobacter jejuni and Campylobacter coli strains from healthy sheep

The objectives of this study were to identify, at species level, thermophilic campylobacters isolated from clinically healthy sheep by a multiplex polymerase chain reaction (mPCR). The heterogeneity among Campylobacter jejuni and C. coli isolates was also investigated using a restriction fragment length polymorphism (RFLP) analysis of the flagellin (flaA) gene. Samples of intestinal contents, gall bladders and faeces were collected from 610 healthy sheep. While gall bladder samples were plated directly onto Preston agar, an enrichment stage was applied for intestinal and faecal samples. Of the 610 samples, 302 (49.5%) were positive for Campylobacter spp. Using a mPCR assay for species identification, 103 (34.1%) were positive with C. jejuni-specific primers, while 100 (33.1%) were positive with C. coli-specific primers. Additionally, 16 (11.9%) of the intestinal content samples were positive for both species by mPCR. All the isolates identified as C. jejuni and C. coli were successfully subtyped by flaA typing. Of 203 isolates tested, 48 different flaA types were found. Twenty-six flaA types were identified among C. jejuni isolates and the remaining 22 from C. coli isolates.     

Isolation of Campylobacter jejuni and Campylobacter coli from the gall bladder samples of sheep and identification by polymerase chain reaction

In this study, 100 gall bladder samples of sheep slaughtered at an abattoir in Elazi? province were examined for Campylobacter jejuni and Campylobacter coli by culture and polymerase chain reaction (PCR). Preston Campylobacter Agar supplemented with 7% horse blood and Preston Selective Supplement (Oxoid, Hampshire, UK) were used for isolation of the agents. Campylobacter spp. were isolated in 66 samples, and they were identified as 34% C. jejuni and 32% C. coli. A multiplex PCR based upon the use of ceuE gene-specific primers was applied on DNA samples extracted from C. jejuni and C. coli isolates. All C. jejuni and C. coli strains that were positive by culture were also detected to be positive by PCR. This study shows that PCR can be used an alternative, rapid and sensitive test for the identification of C. jejuni and C. coli which threaten human and animal health.     

Serotype and genotype diversity and hatchery transmission of Campylobacter jejuni in commercial poultry flocks.

We investigated the genotype and serotype diversity of Campylobacter coli and C. jejuni in two parent flocks of adult hens and their offspring over two rotations in order to evaluate the role of hatchery mediated transmission and/or vertical transmission of campylobacters in broiler flocks. In total, 314 C. jejuni and 32 C. coli isolates from parent and broiler flocks and from the surroundings of broiler houses were typed by flagellin gene PCR/RFLP (fla-typing), and selected isolates were also typed by serotyping and macrorestriction profiling using PFGE (MRP/PFGE). The combined typing results showed that the broiler flocks could be colonised by 1-3 different Campylobacter clones and parent flocks could be colonised by 2-6 different clones. C. coli was isolated from up to 36% of birds in one parent flock, whereas only C. jejuni was isolated from broiler flocks. C. jejuni clones from different flocks were clearly discriminated by fla-typing as well as by MRP/PFGE, except for a few cases where individual isolates belonging to two different clones were found to have altered fla-types. Similarly, one C. coli clone showed pronounced fla-type variation. The present results lead to the conclusion that vertical transmission or horizontal transmission via the hatchery are not significant transmission routes of C. jejuni to broiler chickens under Danish conditions. In the cases where more than one Campylobacter clone simultaneously colonised flocks, we found that the different clones coexisted in flocks rather than excluding each other.