李氏杆菌病研究进展

李氏杆菌病(listeriosis)又名旋转病(circling disease),是由李氏杆菌引起的一种重要的人畜共患染病。该病发病率较低,但死亡率却很高,各种年龄,不同种类的畜、禽和野生动物以及人类均可感染李氏杆菌而发病,主要以幼龄和妊娠母畜较易感,且发病较急。家畜主要表现为脑膜脑炎、败     

羊李氏杆菌病的流行特点及诊治

羊李氏杆菌病为人兽共患传染病,其主要病原为单核细胞增多性李氏杆菌。该病菌的环境适应能力极强,且具有较强的抵抗力。在常规的环境下,可在土壤、饲料和粪便中存活。一旦发生该病,会对养殖场的发展造成严重影响。笔者介绍了该病的流行特点、临床症状以及诊断方法,最后提出综合性防控建议。     

羊李氏杆菌病的症状、诊断和防治措施

李氏杆菌病是冬春两季高发的一种神经性疾病,成年羊群较易感染,由饲喂发霉变质并污染了单核细胞李氏杆菌的青贮料引起。李氏杆菌存在于土壤、动物胃肠道及排泄物中。消化道传染为该病的主要传播方式,临床上表现为脑炎及其他症状。脑炎型李氏杆菌病,可根据典型的神经症状做出诊断。通过采集病羊的腰脊髓液,可对该病进行初诊。治疗羊李氏杆菌病可选用敏感抗生素,如青霉素、氨苄青霉素、头孢噻呋、红霉素、甲氧苄啶与磺胺类药物。     

一起仔猪李氏杆菌病的诊治

猪李氏杆菌病是一种由产单核细胞李氏杆菌引起的散发性传染病,临床上主要表现为脑膜脑炎、败血症和孕畜流产。该病的发病率一般不高,但死亡率很高,哺乳仔猪感染的年龄越小则死亡率越高。主要对一起仔猪李氏杆菌病的诊疗作一介绍,以期为有效防控该病提供参考。     

一例猪李氏杆菌病的诊治报告

猪李氏杆菌病是由李氏杆菌引起的人、家畜和禽类的共患传染病。猪发病后主要表现为败血症或中枢神经功能障碍。该病多为散发,发病率很低,但病死率很高。如果诊断治疗不当,会造成一定的经济损失。2013年初,我市某猪场发生了李氏杆菌病,现     

羊李氏杆菌病综合防制方法

羊李氏杆菌病是由李氏杆菌引起的传染病,可分为子宫炎型、败血型和脑炎型。绵羊的李氏杆菌病几乎全为脑炎型,各种年龄和性别的绵羊都可患病;败血型间或发生于10日龄以下的羔羊;子宫炎型多发生于怀孕最后2个月的头胎绵羊。该病常散在发生,但致死率高,(一)发病原因绵羊多在冬季和早春发病,散发,有时呈地方性流行,病羊和带菌动物是传染源,老鼠也可能是该病的疫源。病菌通过粪、尿、乳汁以及眼、鼻、     

李氏杆菌病的防控

李氏杆菌病是由产单核细胞李氏杆菌引起的一种食源性、散发性人畜共患病,病死率高,各种年龄的动物均可感染发病.对李氏杆菌病的病原、流行病学特点、临诊症状、病理变化、诊断及防控措施作一介绍,以期为有效防控该病提供参考.     

李氏杆菌病的防控

李氏杆菌病是由产单核细胞李氏杆菌引起的一种食源性、散发性人畜共患病,病死率高,各种年龄的动物均可感染发病。对李氏杆菌病的病原、流行病学特点、临诊症状、病理变化、诊断及防控措施作一介绍,以期为有效防控该病提供参考。     

野鸭李氏杆菌病的诊疗报告

李氏杆菌病是由李氏杆菌引起的一种常见病和多发病,病禽以坏死性肝炎和心肌炎为特征.近年来该病也成了野鸭的一种易感疾病,并给野鸭饲养业造成了较大的经济损失.     

猪李氏杆菌病的诊断与防制措施

李氏杆菌病(listeriosis)是由产单核细胞李氏杆菌引起的一种重要的人畜共惠传染病.猪感染后主要表现为脑膜炎、败血症和流产.由于猪肉是人们主要的肉食来源,猪群一旦感染则会直接影响到食品安全.重点对猪李氏杆菌病的病原、流行病学、诊治等方面进行了阐述,以期为该病的科学防制提供参考.     

Biliary excretion as possible origin of Listeria monocytogenes in fecal carriers.

The presence of Listeria monocytogenes in feces of animals has been related with ingestion of contaminated foods. In the study reported here, healthy mice inoculated SC with L monocytogenes excreted the organism in their feces, regardless of whether they developed clinical signs of infection. Listeria monocytogenes was isolated simultaneously from liver, feces, and bile of inoculated mice, which strongly suggested that the microorganism reached the gastrointestinal tract by biliary excretion.     

新疆不同来源单核细胞增生李斯特氏菌血清型的多重PCR鉴定

为鉴定分离自新疆北疆绵羊单核细胞增生李斯特氏菌,本研究采用多重PCR方法,鉴定来自病发地区部分羊场的发病绵羊、健康绵羊、羊舍环境和乌鸦粪分离的30株李斯特氏菌分离株的8株单核细胞增生李斯特氏菌分离株血清型。结果为4株发病绵羊株有3株鉴定为单核细胞增生李斯特氏菌,血清型为1/2a或4b,1株为非单核细胞增生李斯特氏菌;5株健康绵羊株血清型为1/2a;其余来自羊舍水源的3株、乌鸦粪的2株及健康绵羊16株为非单核细胞增生李斯特氏菌,表明来自发病绵羊、健康绵羊及参考菌株LM血清型之间具有相关性。     

应用环介导等温扩增技术快速检测单核细胞增生李斯特菌的研究

目的建立环介导等温扩增技术快速检测单核细胞增生李斯特菌。方法根据单核细胞增生李斯特菌(LM)hlyA基因序列中的保守区域,采用在线引物设计软件Primer Explorer4.0进行设计,获得一套特异性的环介导等温扩增(LAMP)引物,对单核细胞增生李斯特菌hlyA基因进行LAMP扩增,并与常规PCR方法进行比较。结果建立的LAMP方法能成功扩增出梯形条带,LAMP检测单核细胞增生李斯特菌纯培养物和人工染菌的灵敏度为5.44×102cfu/mL,而对照PCR检测的灵敏度为5.44×104cfu/mL。对10株细菌进行LAMP扩增,仅单核细胞增生李斯特菌得到阳性结果。从DNA提取到报告结果,耗时仅1h。结论 LAMP检测单核细胞增生李斯特菌灵敏度高,特异性强,耗时短,方法简便,有望发展成为快速检测食品中单核细胞增生李斯特菌的有效手段。     

Epidemiological studies on the occurrence of Listeria monocytogenes in the feces of dairy cattle

Seasonal variation in the fecal shedding of Listeria spp. in dairy cattle was examined by collecting a total of 3,878 fecal samples during a period of two years. The prevalences of Listeria spp. and L. monocytogenes were higher during the indoor season (12.7% and 9.2%, respectively) than in samples collected from the animals on pasture (5.3% and 3.1%, respectively). The highest frequencies of Listeria spp. (19.4%) and L. monocytogenes (16.1%) were detected in December. Listeriae were isolated from at least one of the dairy cows from 45.8% of the 249 herds examined. 2.9% of the 314 milk samples collected from the farm bulk tanks on 80 dairy farms on four different occasions yielded L. monocytogenes. The seasonal occurrence of these bacteria in milk reflected the frequencies of Listeria in the fecal material but not those in the main roughage used; grass silage and pasture grass. Fecal material is considered to be a potential source of contamination of raw milk by L. monocytogenes. Investigation of the numbers of viable Listeria organisms in different animal fodders is considered essential in further epidemiological studies of these bacteria.     

Avirulence of viable but non-culturable Listeria monocytogenes cells demonstrated by in vitro and in vivo models

The virulence of Viable But Non-Culturable (VBNC) cells of 4 strains of Listeria monocytogenes was investigated in both a human adenocarcinoma cell line (HT-29) and a mouse model. LO 28, ATCC 19115 and CNL 895807 strains of Listeria monocytogenes became VBNC when incubated in microcosm water at 20 degrees C and Scott A strain at 4 degrees C. No culturable bacteria were detected in the VBNC state, although 104 active cells/mL were found by the Direct Viable Count (DVC) and CTC-DAPI double staining methods. A comparison of virulence in both human adenocarcinoma cell line HT-29 and the mouse model showed that culturable controls were more virulent than VBNC cells, which appeared to be avirulent regardless of the virulence methods applied. Pathogenicity was tested in each model and was lost concomitantly with culturability, whereas some cells were still metabolically active (determined by CTC and DVC). Moreover, amplification of a 388 bp fragment with Immunocapture-PCR revealed the presence of Listeria monocytogenes DNA in all mixed spleen samples after intravenous injection of VBNC cells. These results demonstrate that VBNC cells were present in the mouse spleens. The results of the study suggest that Listeria monocytogenes strains might remain in the aquatic environment for prolonged periods in the VBNC state but these cells were not pathogenic in the conditions tested. These findings demonstrate the value of VBNC studies and show the need to investigate the role of VBNC cells in environmental transmission of Listeria monocytogenes. Further studies are needed in order to investigate the virulence of VBNC cells of Listeria monocytogenes after recovery of a culturable state.     

哈尔滨市鲜肉中单核细胞增生性李斯特菌的分离鉴定及耐药性分析

为了解哈尔滨市单核细胞增生性李斯特茵(Lm)的污染状况及耐药状况.在哈尔滨市市场随机采集158份鲜肉样品,采用显色培养基分离,API试剂条和PCR鉴定等方法对样品中的Lm进行分离鉴定,并通过Kirby-Barer法测定分离菌株对24种抗生素的耐药性.结果从鲜肉中共分离到Lm 23株,检出率为14.56%,其中鲜猪肉检出率最高,达20.00%(14/70);23株分离菌株中耐药菌株为22株,耐药率高达95.65%.这表明哈尔滨市鲜肉中存在一定程度的Lm污染,并且分离菌株存在较严重的耐药现象.应加强控制动物饲料亚治疗抗生素的使用并严格遵守休药期,防止耐药菌株产生进而控制食源性疾病的发生.     

The occurrence of Listeria in the production of processed meat, salami and mettwurst

In six Swiss meat-processing plants 206 samples of cured and air-dried beef (Bündnerfleisch), salami and Mettwurst were analyzed for the presence of Listeria spp. Samples were taken during the fabrication, fermentation and drying of the products. Out of 44.7% of all samples Listeria spp. could be detected. 6.8% turned out to be L. monocytogenes, 37.4% L. innocua and 0.5% L. seeligeri. Listeria spp. were found in all production stages of the tested foods. The concentration of L. monocytogenes was always less than or equal to 20 MPN/g. 86% of the isolated strains formed part of the serogroup 1/2 and 14% of the serogroup 4. Listeria spp. could only be found on the surface of Bündnerfleisch. Both, L. monocytogenes and L. innocua were able to survive the maturation process of salami, even when the initial concentration was very low. The ripening was more often survived by L. innocua than by L. monocytogenes. It appeared that Mettwurst had the highest contamination rate of Listeria spp. (94.4%), followed by salami (46.7%) and Bündnerfleisch (23.1%). The corresponding proportions for L. monocytogenes were 8.0% (salami), 5.8% (Bündnerfleisch) and 0% (Mettwurst). Listeria spp. positive samples were found in every examined plant, L. monocytogenes in five of therm. The Listeria spp. contamination rates moved from 10.0% to 86.2%, those of L. monocytogenes from 0% to 12.1%.     

Pyrolysis mass spectrometry of Listeria monocytogenes isolates from sheep.

Forty-eight isolates of Listeria monocytogenes from sheep and silage, involved in five small outbreaks of listeriosis, were compared by pyrolysis mass spectrometry (PyMS). The method clustered isolates from single animals, and showed that epidemiologically associated isolates were closely related to each other. PyMS is a simple technique capable of analysing large numbers of samples daily, and its application in veterinary studies should help to elucidate the epidemiology of listeriosis.     

Influence of bacteriocin-like substance, generation times, and genetic profiles of Listeria innocua on the isolation of Listeria monocytogenes

Inhibition of isolation of Listeria monocytogenes by bacteriocin-like substance (BLS)-producing Listeria innocua after enrichment culture was investigated. When 26 L. monocytogenes strains were examined in combination with eight L. innocua strains using the spot on lawn method, 52/208 (25.0%) combinations showed the growth inhibition of L. monocytogenes. When two Listeria species were cultured simultaneously in selective enrichment broth, inhibition of isolation of L. monocytogenes was observed in 12/52 of the combinations at 24h (23.1%), in 24/52 at 48h (46.2%) and in 30/52 (57.7%) after 7 days of incubation. The randomly amplified polymorphic DNA profiles showed no interstrain similarities between either strains of the BLS-producing L. innocua or the BLS-sensitive L. monocytogenes strains. Therefore inhibition by BLS-producing L. innocua of isolation of L. monocytogenes after enrichment culture is unlikely to be dependent upon a particular genetic profile.     

单核细胞增多性李氏杆菌人工感染绵羊试验

将人从病羊脑分离纯化的单核细胞增多性李氏杆菌经列脉接种于健康得奴绵羊３只,结果被感染绵羊均表现出与自然感染绵羊相同的临床症状和病理变化,并从脑、心血、淋巴结中回收到了单核细胞增钨生李氏杆菌,从而证明了该分离株单核细胞增多性李氏杆菌具有较强的致病性。