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根据GeneBank上发表的单核细胞增多性李氏杆菌(Listeria monocytogenes,LM)的内化素B(internalin B,inlB)和肌动蛋白A(actin A,actA)基因设计特异性引物,对5株不同来源的健康绵羊单核细胞增多性李氏杆菌和一株临床分离的单核细胞增多性李氏杆菌的inlB及actA基因进行PCR扩增,克隆测序分析其序列,并对2株部分基因缺失的单增李氏杆菌进行小鼠攻毒试验。结果表明:5株健康绵羊分离株单增李氏杆菌与临床分离株有较高的同源性,并且发现2株部分基因缺失的单增李氏杆菌;小鼠攻毒试验表明缺失株毒力有降低,但是不明显。 相似文献
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四川阿坝州牦牛源溶血性大肠杆菌血清型鉴定及毒力相关基因检测 总被引：1，自引：0，他引：1
为了解牦牛源溶血性大肠杆菌血清型及毒力相关基因,本研究从四川阿坝州采集的牦牛鼻腔棉拭子中分离鉴定溶血性大肠杆菌,并通过玻板凝集结合试管凝集试验鉴定其血清型,采用PCR方法检测大肠杆菌的4个溶血素基因及其它7个毒力相关基因。结果显示,从临床健康的牦牛鼻腔中分离鉴定出74株溶血性大肠杆菌,分离率为19.2%(74/386)。O血清型鉴定结果显示,74株牦牛源溶血性大肠杆菌中已确定O血清型的菌株有60株,共24种O血清型,其余14株未能定型。PCR检测与溶血素相关的4个基因携带率分别为96.0%(hly A)、86.5%(hly E)、14.9%(ehly)和2.7%(ehx);有4种溶血素基因组合,分别为hly A~+(96.0%),hly E~+(86.5%),hly A/hly E双阳性(80.9%),ehx/hly E双阳性(2.7%);其它毒力相关基因的检出率分别为93.2%(irp2)、93.2%(fyu A)和2.7%(stx2);LT、STa、STb和K99基因未检出。研究结果表明,溶血性大肠杆菌存在于临床健康牦牛鼻腔内,血清型复杂且无优势血清型,大肠杆菌溶血素相关基因和高致病性毒力岛相关基因携带率高。本研究首次对四川阿坝州牦牛源溶血性大肠杆菌的血清型和毒力相关基因进行了研究,提示在牦牛中存在溶血性大肠杆菌的潜在威胁。 相似文献
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《动物医学进展》2021,42(10)
采集甘肃省兰州市、定西市、张掖市、酒泉市和庆阳市等地区部分屠宰场和农贸市场共1 387份样品。通过常规细菌学和分子鉴定方法对样品进行单核细胞增生李斯特菌分离鉴定,并对分离菌株的耐药性、血清型以及生物被膜形成能力进行测定。1 387份样品中共分离出14株单核细胞增生李斯特菌,总分离率为1.0%。选择12种抗菌药物进行纸片扩散法(KB)药敏性检测,结果表明分离菌株对四环素和头孢噻吩耐受最严重,耐药率为100%。青霉素、乙酰螺旋霉素、复方新诺明、红霉素、磷霉素和多黏菌素,多重耐药严重。血清型鉴定结果表明1/2a血清型菌5株(35.7%),1/2b血清型菌2株(14.3%)1/2c血清菌6株(42.9%),4b血清型菌1株(7.1%)。同时,分离株均能形成生物被膜,其中1/2a、1/2b和1/2c血清型菌株形成生物被膜的能力较强。研究表明,甘肃省畜禽肉品中存在单核细胞增生李斯特菌污染,农贸市场中污染最严重,相关部门应加强监控,从而预防食源性疾病的发生。 相似文献
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为建立利用重组李氏杆菌溶血素(LLO)检测单核细胞增生李氏杆菌的ELISA方法,试验首先优化了重组李氏杆菌溶血素的表达条件,获得纯度较高的包涵体之后,用亲和层析法纯化重组李氏杆菌溶血素蛋白,并用纯化蛋白免疫试验兔获得诊断抗体,然后建立阻断ELISA检测单核细胞增生李氏杆菌的方法,并分析最低检测菌数.结果表明:在振摇培养条件下,当IPTG浓度为0.6 mmol/L、诱导温度为37 ℃、菌液OD600值为0.25时开始诱导,诱导时间为150 min,重组李氏杆菌溶血素的表达量最大;纯化蛋白浓度为480 μg/mL,具有免疫活性.说明建立的检测方法特异性好,最低检测菌数为4.8×106个/mL.提示利用重组李氏杆菌溶血素检测单核细胞增生李氏杆菌的ELISA方法是可行的,具有潜在的应用价值. 相似文献
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单核细胞增多性李氏杆菌人工感染绵羊试验 总被引：2，自引：0，他引：2
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。 相似文献
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动物李氏杆菌病病原主要有两种,分别是单核增多症李氏杆菌和伊氏李氏杆菌(仅引起动物发病),前者是主要的,它是一种危害严重的人畜共患病病原体。人畜感染后主要表现脑膜炎、败血症、流产及单核细胞增多。近几年来,新疆先后有5个地区的3个牧区、4个农区养羊场爆发以神经症状为主要特征的李氏杆菌病,造成1 300余只羔羊死亡,经从绵羊实质器官和饲草中分离培养和形态学观察,初步确定为7株李氏杆菌,分别命名为90SB1、90SB2、90SB5、90SS1、125SL1、G1和饲草李。结合溶血试验、动物试验,再进行PCR特异性扩增,确定前5株为单核细胞增多症李氏… 相似文献
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Yoshida T Sugimoto T Sato M Hirai K 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2000,62(6):673-675
Between 1991 and 1993, the intestinal contents and feces of wild animals in Japan were examined for the presence of Listeria. The wild animals examined included 623 mammals (11 species) and 996 birds (18 species). Listeria species were isolated from 38 (6.1%) of the 623 mammalian samples and 133 (13.4%) of 996 bird samples. The highest incidence of Listeria in the mammals was found in Japanese monkeys (20.0%) and that in birds was found in crows (43.2%). The incidence of Listeria in Japanese monkeys varied from 0 to 40.0% depending on the capture area. L. monocytogenes was isolated from II of these positive samples. Serovars 1/2a and 4b predominated in eight serotyped L. monocytogenes isolates. 相似文献
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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。 相似文献
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J F Fernandez-Garayzabal M Blanco J A Vazquez-Boland V Briones J A Garcia C Delgado M Domingo J Marco L Dominguez 《Zentralblatt für Veterin?rmedizin. Reihe B. Journal of veterinary medicine. Series B》1992,39(7):513-518
Twenty-two silage samples were analyzed for the presence of L. monocytogenes using five Listeria selective plating media, with and without previous selective enrichment step. L. monocytogenes was recovered from 3 samples by both procedures, but direct plating allowed the quantification of Listeria population. Two of these positive samples were implicated in outbreaks of listeriosis in sheep; the L. monocytogenes population in these samples was about 10(6) cells/g. The L. monocytogenes population in the other positive sample was 10(3) cells/g. Direct isolation of L. monocytogenes was only possible from LPM, PALCAM and LSAMm media. MOX and LSM media were not selective enough to allow direct Listeria isolation. In our hands, LSAMm was the most suitable plating medium for the direct isolation and specific quantification of L. monocytogenes from silage employing a red blood cells overlay technique. 相似文献
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绵羊源爱知病毒D型(ovine Aichivirus D)是在国内绵羊中新发现的病毒,本研究根据绵羊源Aichivirus D 3D基因序列设计检测引物,通过反应体系和条件优化,成功建立了检测绵羊源Aichivirus D的TB Green染料法荧光RT-PCR方法,该方法特异性和稳定性良好,灵敏度高。对2020年4月―2021年5月采集自四川6个场253份绵羊粪便样本(健康羊的133份,腹泻羊的120份)进行检测,结果该病毒的平均检出率为8.7％,场阳性率为66.7％。其中,腹泻粪便样本中绵羊源Aichivirus D阳性率(17.5%)显著高于非腹泻粪便样本中绵羊源Aichivirus D阳性率(0.75%,P<0.001)。表明绵羊源Aichivirus D可能是引起以上地区绵羊腹泻的病原。从绵羊源Aichivirus D的阳性样本中成功克隆出大小为1 422 bp的13个完整的绵羊源Aichivirus D 3D基因,其核苷酸相似性为99.4％～100.0％。遗传演化分析发现这13株绵羊源Aichivirus D 3D基因与本实验室前期研究上传的绵羊源Aichivirus D 3D基因共同聚为单独的一个大支。本研究为绵羊源Aichivirus D的分子检测提供了一种新的方法和基础流行病学数据。 相似文献
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Nightingale KK Fortes ED Ho AJ Schukken YH Grohn YT Wiedmann M 《Journal of the American Veterinary Medical Association》2005,227(11):1808-1814
OBJECTIVE: To assess seasonal variation in prevalence of Listeria monocytogenes on ruminant farms and identify management practices associated with ruminant listeriosis and fecal shedding of L. monocytogenes. STUDY DESIGN: Case-control study. SAMPLE POPULATION: 2056 samples of feces, feed, soil, and water from 24 case farms with listeriosis and 28 control farms without listeriosis. PROCEDURE: Samples were collected and evaluated via bacterial culture for L. monocytogenes. Univariate associations between farm management practices and listeriosis and fecal shedding of L. monocytogenes were assessed. Multivariate models were developed to identify farm management practices associated with listeriosis and fecal shedding of L. monocytogenes. RESULTS: The prevalence of L. monocytogenes on cattle, goat, and sheep farms was seasonal, especially in fecal samples, with peak prevalence in winter. Although the prevalence of L. monocytogenes in feedstuffs from small-ruminant farms also peaked during winter, the bacterium was detected at a constant rate in cattle farm feedstuffs throughout the year. Farm management practices, animal health and hygiene, and feedstuff quality and storage were associated with ruminant listeriosis and fecal shedding of L. monocytogenes. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that the prevalence of L. monocytogenes on ruminant farms is seasonal, management practices are associated with ruminant listeriosis and fecal shedding of L. monocytogenes, and the epidemiologic features of listeriosis differ in cattle versus small ruminants. Awareness of risk factors may be used to develop control measures to reduce animal disease and introduction of L. monocytogenes into the human food chain. 相似文献
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The aim of this study was to determine the simultaneous occurence of Salmonella spp., L. monocytogenes, verotoxigenic E. coli (VTEC), and Campylobacter spp. in slaughtered cattle and in beef meat subjected for human consumption. A total of 406 bovine hides and 406 corresponding carcasses were used to collect the samples with a swab method after exsanguination and evisceration of animals, respectively. Furthermore, 362 beef meat samples were purchased in local retail shops over the same period of time as for the bovine samples. Food-borne bacterial pathogens were identified with standard ISO methods with some modification by the use of PCR for VTEC. The isolated bacteria were then molecularly speciated (Campylobacter), serotyped (L. monocytogenes) and characterized for the presence of several virulence marker genes (VTEC and Campylobacter). It was found that 49 hide (12.1%) and 3 (0.7%) carcass samples were contaminated with more than one bacterial pathogen tested. Most of the hides were positive for Campylobacter spp. and VTEC (27 samples) and Campylobacter spp. together with L. monocytogenes (12 samples). Eight bovine hides contained L. monocytogenes and VTEC while L. monocytogenes and Salmonella spp. were detected in one sample. Furthermore, 3 pathogens (Campylobacter spp., L. monocytogenes and VTEC) were simultaneously identified in one bovine hide tested. In case of bovine carcasses 2 samples contained Campylobacter spp. and VTEC whereas one carcass was positive for L. monocytogenes and VTEC. On the other hand, 10 out of 362 (2.8%) minced beef samples were contaminated with at least two pathogens tested. The majority of these samples were contaminated with L. monocytogenes and Salmonella spp. (6 samples). It was noticed that equal number of C. jejuni and C. coli were found, irrespective of the origin of the samples. Most of the strains possessed more than one pathogenic factor as identified by PCR. Molecular serotyping of L. monocytogenes revealed that the majority of the isolates (27 out of 31; 87.1%) belonged to 1/2a serogroup. It was found that most of the VTEC isolates possessed the Shiga toxin stx2 gene (12 strains) whereas only 2 strains were str1-positive. The eneterohemolysin and intimin markers were identified only in 7 and 2 isolates, respectively. PCR analysis revealed that 4 VTEC belonged to O91 serogroup, 2 strains were O145 and 1 isolate was identified as O113. None of the VTEC detected in the study was O157 serogroup. 相似文献
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Our purpose was to identify the main hazards associated with the spread of Listeria monocytogenes in dairy products in Switzerland and to determine the changes in predominant serotypes of the isolates, using databases on dairy-processing and environments from the Swiss Dairy Research Station during the years 1990-1999. Overall, of 76,271 samples collected, 3722 (4.9%) were positive for the presence of L. monocytogenes. Cheese-ripening facilities had the highest proportion of positive samples (7.6%), followed by small-scale local dairies (4.4%). By sample type, the highest proportion of positive samples (9.5%) was observed in water samples used for cheese-washing, followed by cheese-surface swabs (5.0%). During the 10-year period, no positive samples were obtained from cream, ice cream, milk powder, yogurt, or fresh cheese. Of 3722 L. monocytogenes isolates, 1328 (35.7%) were serologically typeable. Serotypes 1/2a, 1/2b, and 4b accounted for 92.7% of the 1328 isolates. Until 1995, the most-prevalent serotype was 1/2b (annual proportional prevalence 39.3-72.2%)--whereas since 1996, 1/2a was the most prevalent (34.7-54.7%). During 1996-1999, serotype 1/2a increased by 88%, compared to the average of 1990-1995. In the final random-effect multivariable logistic model, the strongest predictor of a positive culture was samples from cheese-ripening plant (OR=1.54; 95% CI: 1.14, 2.08) and the second-strongest predictor was samples collected by someone who was employed by the plant (OR=1.48; 1.29, 1.71). Hard and semi-hard cheeses were more likely to be associated with serotype 1/2b and soft cheeses with serotype 1/2a. 相似文献
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Two juvenile scimitar-horned oryx (Oryx dammah) at the Wild Animal Park Planckendael died from acute septicemia caused by Listeria monocytogenes serovar 4b. Subsequently, Listeria spp. were isolated from the feces, food, and environment of seven antelope species and examined using a two-stage enrichment procedure in Fraser Broth, followed by isolation on PALCAM agar. A total of 40/170 samples (23.5%) was positive for Listeria spp. No organisms were cultured in 83/170 samples (48.8%), and 47 samples (27.6%) were overgrown with Bacillus spp. Nonpathogenic Listeria spp. were isolated from 16/70 fecal samples, 22/40 soil samples, and 2/60 feed samples. Listeria monocytogenes serovar 1/2b was isolated from two soil samples collected in the enclosure of the scimitar-horned oryx. 相似文献
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Irene V Wesley David J Larson Karen M Harmon John B Luchansky Ann Ramos Schwartz 《Journal of veterinary diagnostic investigation》2002,14(4):314-321
A case of ovine listeriosis was examined in a flock of sheep. The index case was a male lamb, which was part of a flock of 85 sheep located in central Iowa. Because the sheep were raised on a premise where soybean sprouts were also cultivated for the organic foods market, the potential of a public health concern was addressed. To identify the source of contaminations, clinical and environmental samples were cultured for Listeria monocytogenes. Isolates were serotyped and analyzed using pulsed-field gel electrophoresis (PFGE). Listeria monocytogenes (serotype 1) was recovered from the brain of a male lamb with clinical signs of listerial encephalitis. Isolates of serotypes 1 and 4 were also cultured from feces of clinically healthy lambs, compost piles, and soybean cleanings. By PFGE, the clinical isolate was distinctly different from the other isolates. Environmental isolates were identified as L. monocytogenes serotypes 1 and 4. However, by PFGE, none matched the profile of the single clinical isolate. Thus, the ultimate source of contamination is unknown. 相似文献
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Michael P Ward Catherine A Alinovi Laurent L Cou?til Ching Ching Wu 《Journal of veterinary diagnostic investigation》2005,17(2):118-123
The diagnostic accuracy of a PCR used to identify horses shedding Salmonella spp. in their feces during hospitalization was estimated, relative to bacterial culture of serially collected fecal samples, using longitudinal data. Five or more fecal samples were collected from each of 116 horses admitted as inpatients, for reasons other than gastrointestinal disease, between July 26, 2001 and October 25, 2002. All 873 fecal samples collected were tested with a PCR based on oligonucleotide primers defining a highly conserved segment of the histidine transport operon gene of Salmonella typhimurium, and each sample was cultured for Salmonella spp. One or more samples from 87 (75%) horses were PCR positive, and Salmonella was cultured from 1 or more samples from 11 (9.5%) horses. All culture-positive horses had at least 1 PCR-positive result, whereas only 29 (28%) culture-negative horses were PCR negative on all fecal samples tested. The PCR was most specific, relative to bacterial culture of serially collected fecal samples, when used to test samples from Quarterhorse or breeds other than Thoroughbred or Standardbred, or from clinical (vs. healthy, accompanying horses) cases. Overall, the PCR had the greatest agreement (70%), compared with bacterial culture of serially collected fecal samples, using a cutoff of 2 or more positive PCR test results to define a Salmonella-positive horse. The reasons why some fecal samples, from which Salmonella organisms cannot be isolated, are PCR positive need to be determined before the PCR can be incorporated into Salmonella surveillance programs for hospitalized equine populations. 相似文献