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为探明引起贵州省某鸭场雏鸭发病的病原及其致病性和耐药情况，本研究对该鸭场送的疑似细菌感染病鸭进行剖检，取鼻黏膜、心脏和肝脏等组织器官接种于培养基中进行细菌分离鉴定，通过对分离菌进行药敏试验、动物回归试验和毒力基因检测研究其耐药情况和致病性。结果显示，分离菌在血琼脂培养基上生长16 h后呈现为边缘整齐、有光泽的乳白色菌落，伴有β-溶血现象，经革兰氏染色后在生物显微镜下呈两端钝圆、弧状、排列无规则的革兰氏阴性短小杆菌，与霍乱弧菌相符；16S rDNA基因序列同源性及系统进化树显示，该分离菌与霍乱弧菌同源性高达99.6%~99.7%聚为一支；药敏试验结果显示，分离菌对大部分药物都表现为耐药，其中对氨苄西林、克林霉素、复方新诺明、苯唑西林和克林霉素等抗菌药耐药性较强，对头孢哌酮和头孢曲松敏感；动物回归试验显示，分离菌可导致试验组雏鸭5 d内全部发病死亡，表明该分离菌对雏鸭具有较强的致病性；毒力基因PCR检测结果显示，检测的霍乱弧菌相关毒力基因hlyA、ompW和chxA为阳性，而检测的O1群rfb、O139群rfb、tcpA及ctxA基因为阴性，表明本次分离的霍乱弧菌携带有致病基因，但不属于O1和O139血清群。结果表明，该鸭场雏鸭发病的疫情病原为非O1/O139血清群霍乱弧菌，该菌致病性强且对多种抗菌药物耐药。本试验结果为贵州省鸭霍乱弧菌病的防控提供了参考依据。 相似文献
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《中国预防兽医学报》2019,(9)
为鉴定人工养殖的湘华鲮出现大量由急性肠炎引起死亡的病原,本研究取病鱼腹水和肠道粘液进行病原菌分离纯化,获得菌株XHL-03。经人工感染试验验证,人工感染的湘华鲮出现与自然发病相同的症状,初步确定其为该病致病菌株。经细菌形态学、生理生化特征、16S r DNA序列分析及系统发育树聚类和血清凝集试验检测,结果显示致病菌株XHL-03为非O1/非O139型霍乱弧菌,其对诺氟沙星、头孢曲松、新霉素等10种药物高度敏感。病理切片显示,感染病原的湘华鲮肝胰脏细胞出现坏死,有急性胰腺炎和肠炎综合症状。本研究为湘华鲮霍乱弧菌引起的急性肠炎的临床诊断和防控提供参考依据。 相似文献
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四川省某藏鸡场藏鸡发生以鼻腔与窦发炎、颜面肿胀、流鼻涕和打喷嚏为主要特征的疾病,通过对送检病鸡病原的分离纯化、生化鉴定、16 S rDNA基因的克隆和序列分析诊断为副鸡嗜血杆菌感染,将该株副鸡嗜血杆菌的16 S rDNA序列与GenBank中15株巴氏杆菌科菌株进行同源性分析发现,与6株副鸡嗜血杆菌同源性较高,为94.2%～97.2%,与其它菌株16 S rDNA基因的同源性较低。另外,药敏试验表明,本菌株对菌必治、阿莫西林、庆大霉素、头孢氨噻肟和阿奇霉素等药物敏感。 相似文献
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泥鳅源霍乱弧菌的分离鉴定及药敏试验 总被引：1，自引：0，他引：1
《中国预防兽医学报》2016,(1)
为探究引起江苏某渔场泥鳅发病死亡的病原,本研究对其病变组织进行细菌分离,获得一株优势生长细菌;通过对该菌株的形态观察、生理生化特性检测、16S r RNA基因测序比对及系统发育树聚类,结果表明该分离株为霍乱弧菌(V.cholerae),将其命名为BH-1;回归试验证实该菌为致病菌,能够导致健康泥鳅死亡;药敏试验结果表明该分离菌株对氨曲南、强力霉素、庆大霉素等29种药物高度敏感,对头孢唑啉、青霉素G、乙酰螺旋霉素等6种药物中度敏感,对苯唑西林、万古霉素、林可霉素等8种药物已产生耐药性。本研究确定霍乱弧菌BH-1为引起该渔场泥鳅大量死亡的病原,本研究结果为该病防治提供实验依据。 相似文献
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为了研究分离自患病瓯江彩鲤的1株气单胞菌(HX201006-2)的分类地位与药敏特性,试验采用细菌的16S rDNA基因的分类鉴定与生化方法对该分离菌进行研究,通过NCBI的Blast搜索同源序列,应用MegAlign软件进行序列比对并构建系统发育树。结果表明:该分离菌的16S rDNA(GenBank登录号为JF713702.1)基因,与简达气单胞菌类聚,初步确定该分离菌株的分类地位,结合分离菌的形态、生理生化特征,鉴定该分离菌为简达气单胞菌;该分离菌对头孢噻吩、丁胺卡那、庆大霉素等12种药物敏感;对新霉素、利福平、红霉素3种药物中度敏感;对头孢拉定、多黏菌素B和O/129等7种药物存在不同程度的耐药性。 相似文献
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A case of enterotoxicosis in a goat at necropsy is described. The animal had died without clinical signs. Toxigenic Vibrio cholerae non-O:1 was isolated from the intestines. This species has not been reported earlier from healthy or diseased farm animals, such as goats, in the Netherlands. 相似文献
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Bennett J Bettelheim KA 《Comparative immunology, microbiology and infectious diseases》2002,25(2):77-84
Verocytotoxigenic Escherichia coli (VTEC) were isolated from meat in New Zealand. They were tested for the presence of virulence factors associated with VTEC and serotyped. Some of the serotypes found were identical to ones reported from other parts of the world, but some serotypes were also found which had not been reported elsewhere. This study confirms the world-wide distribution of these emerging food-borne pathogens. 相似文献
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The aims of this study were to determine the prevalence of Shiga toxin-producing Escherichia coli (STEC) strains in pigs as a possible STEC reservoir in India as well as to characterize the STEC strains and to determine the antimicrobial resistance pattern of the strains. A total of 782 E. coli isolates from clinically healthy (n?=?473) and diarrhoeic piglets (309) belonging to major pig-producing states of India were screened by the polymerase chain reaction (PCR) assay for the presence of virulence genes characteristic for STEC, that is, Shiga toxin-producing gene(s) (stx1, stx2), intimin (eae), enterohemolysin (hlyA) and STEC autoagglutinating adhesin (Saa). Overall STEC were detected in 113 (14.4 %) piglets, and the prevalence of E. coli O157 and non-O157 STEC were 4 (0.5 %) and 109 (13.9 %), respectively. None of the O157 STEC isolates carried gene encoding for H7 antigen (fliCh7). The various combinations of virulence genes present in the strains studied were stx1 in 4.6 %, stx1 in combination with stx2 gene in 5.1 %, stx1 in combination with stx2 and ehxA in 0.6 %, stx1 in combination with stx2 and eae in 0.2 % and stx2 alone in 3.7 %. All STEC isolates were found negative for STEC autoagglutinating adhesin (Saa). The number of STEC isolates which showed resistance to antimicrobials such as ampicillin, tetracycline, streptomycin, lincomycin, nalidixic acid, sulfadiazine, penicillin, gentamicin, kanamycin and ceftriaxone were 100, 99, 98, 97, 95, 94, 92, 88, 85 and 85, respectively. Ninety-seven isolates showed resistance to more than 2 antimicrobials, and 8 resistance groups (R1 to R8) were observed. This study demonstrates that pigs in India harbour both O157 and non-O157 STEC, and this may pose serious public health problems in future. 相似文献
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Characterization of non-O157 shiga toxin-producing Escherichia coli isolates from healthy fat-tailed sheep in southeastern of Iran 总被引：1，自引：0，他引：1
The objectives of this study were to determine the presence and prevalence of non-O157 shiga toxin-producing Escherichia coli (STEC) isolates from faeces of healthy fat-tailed sheep and detection of phylogenetic background and antibiotic resistance profile of isolates. One hundred ninety-two E. coli isolates were recovered from obtained rectal swabs and were confirmed by biochemical tests. Antibiotic resistance profiles of isolates were detected and phylogenetic background of isolates was determined according to the presence of the chuA, yjaA and TspE4.C2 genetic markers. The isolates were examined to determine stx 1 , stx 2 and eae genes. Non-O157 STEC isolates were identified by using O157 specific antiserum. Forty-three isolates (22.40 %) were positive for one of the stx 1 , stx 2 and eae genes, whereas 10.42 % were positive for stx 1 , 19.38 % for eae and 2.60 % for stx 2 gene. None of the positive isolates belonged to O157 serogroup. Twenty isolates possessed stx 1 were distributed in A (six isolates), B1 (13) and D (one) phylogroups, whereas stx 2 positive isolates fell into A (three isolates) and B1 (two) phylogenetic groups. Eighteen isolates contained eae gene belonged to A (five isolates), B1 (seven) and D (six) phylogroups. The maximum and minimum resistance rates were recorded against to penicillin and co-trimoxazole respectively. The positive isolates for stx 1 , stx 2 and eae genes showed several antibiotic resistance patterns, whereas belonged to A, B1 and D phylogroups. In conclusion, faeces of healthy sheep could be considered as the important sources of non-O157 STEC and also multidrug-resistant E. coli isolates. 相似文献
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Zweifel C Schumacher S Blanco M Blanco JE Tasara T Blanco J Stephan R 《Veterinary microbiology》2005,105(1):37-45
A total of 42 Shiga toxin-producing (STEC) strains from slaughtered healthy cattle in Switzerland were characterized by phenotypic and genotypic traits. The 42 sorbitol-positive, non-O157 STEC strains belonged to 26 O:H serotypes (including eight new serotypes) with four serotypes (O103:H2, O113:H4, O116:H-, ONT:H-) accounting for 38.1% of strains. Out of 16 serotypes previously found in human STEC (71% of strains), nine serotypes (38% of strains) were serotypes that have been associated with hemolytic-uremic syndrome (HUS). Polymerase chain reaction (PCR) analysis showed that 18 (43%) strains carried the stx1 gene, 20 strains (48%) had the stx2 gene, and four (9%) strains had both stx1 and stx2 genes. Of strains encoding for stx2 variants, 63% were positive for stx2 subtype. Enterohemolysin (ehxA), intimin (eae), STEC autoagglutinating adhesin (saa) were detected in 17%, 21%, and 19% of the strains, respectively. Amongst the seven intimin-positive strains, one possessed intimin type beta1 (O5:H-), one intimin gamma1 (O145:H), one intimin gamma2/theta, (O111:H21), and four intimin epsilon (O103:H2). The strains belonged to 29 serovirotypes (association between serotypes and virulence factors). O103:H2 stx1eae-epsilon ehxA, O116:H- stx2, and ONT:H- stx2c were the most common accounting for 29% of the strains. Only one strain (2.4%) of serovirotype O145:H- stx1stx2eae-gamma1ehxA showed a pattern of highly virulent human strains. This is the first study providing characterization data of bovine non-O157 STEC in Switzerland, and underlining the importance of the determination of virulence factors (including intimin types) in addition to serotypes to assess the potential pathogenicity of these strains for humans. 相似文献
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Occurrence and antimicrobial resistance of E. coli non-O157 isolated from beef in Mato Grosso,Brazil
Castro Vinicius Silva Teixeira Larrayane Albuês Carvalho Rodrigues Dália dos Prazeres dos Santos Luis Fernando Conte-Junior Carlos Adam Figueiredo Eduardo Eustáquio de Souza 《Tropical animal health and production》2019,51(5):1117-1123
Tropical Animal Health and Production - Shiga toxin–producing Escherichia coli (STEC) is an important public health concern pathogen, as it produces two toxins, Stx1 and Stx2, with cytotoxic... 相似文献
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Presence of non-O157 Shiga toxin-producing Escherichia coli in feces from feedlot cattle in Alberta and absence on corresponding beef carcasses. 
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下载免费PDF全文 David G Renter Valerie Bohaychuk Joyce Van Donkersgoed Robin King 《Canadian journal of veterinary research》2007,71(3):230-235
The study objectives were to determine the prevalence and serotypes of non-O157 Shiga toxin-producing Escherichia coli (STEC) in pens of feedlot cattle and on corresponding beef carcasses. We collected 25 fecal samples from 84 pens in 21 Alberta feedlots and 40 carcass swabs from each preslaughter pen for analysis by culture and polymerase chain reaction (PCR). Non-O157 STEC were recovered from feces from 12 (14%) of the 84 pens and 12 (57%) of the 21 feedlots by examination of 1 E. coli isolate positive for 4-methylumbelliferyl-beta-beta-glucuronide per sample. Twelve non-O157 serotypes were detected, but 7 of the 15 STEC isolates lacked the accessory virulence genes eae and hlyA. Although 115 (7%) of the carcass broths were PCR-positive, no STEC isolates were recovered from the 1650 carcasses sampled. Our data indicate that multiple non-O157 STEC serotypes may be present in cattle feces, yet are unlikely to be recovered from the corresponding beef carcasses when 20 colonies per sample from PCR-positive broth cultures are analyzed. 相似文献
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Three-hundred and forty-five herds (17 swine, 122 dairy sheep, 124 beef and 82 dairy cattle) were investigated for prevalence of Shiga toxin-producing Escherichia coli (STEC). Rectal faecal samples were selectively enriched and then examined by immunodetection techniques (Immunomagnetic Separation with anti-E. coli O157 Dynabeads, ImmunoMagnetic cell Separation (IMS) and automated enzyme-linked fluorescent immunoassay using VIDAS) and polymerase chain reaction (PCR) (rfbE and fliC genes) to assess the prevalence of E. coli O157:H7. Prevalence of non-O157 STEC was estimated by PCR screening for stx genes of 10 lactose-positive colonies grown on MacConkey agar after enrichment. PCR was used on all STEC isolates to detect stx(1), stx(2), eaeA and E-hlyA genes. Both immunodetection methods showed a moderate-good level of agreement (kappa = 0.649) but IMS showed 87.5% complementary sensitivity. Prevalence of positive herds for E. coli O157:H7 was estimated at 8.7% for sheep and 3.8% for cattle, whereas all the porcine herds tested negative. Non-O157 STEC were also absent from swine, but were isolated more frequently from ovine (50.8%) than bovine herds (35.9%). Within-herd prevalences of excretion of E. coli O157:H7 established by individual testing of 279 sheep (six herds) and 30 beef cattle (one herd) were 7.3% and 6.7% respectively. PCR analysis of 49 E. coli O157:H7 and 209 non-O157 isolates showed a different distribution of virulence genes. All E. coli O157:H7 were stx(2) gene-positive, eaeA was detected in 95.9%, and the toxigenic profile stx(2)/eaeA/E-hlyA was present in 75.5% of the isolates. Among the non-O157 STEC, prevalence of eaeA was significantly lower (5.3%) and E-hlyA was present in 50.2% of the isolates but only sporadically associated with eaeA. stx(2) was predominant in non-O157 isolates from cattle, whereas in sheep the combination stx(1)/stx(2) was more prevalent. This study demonstrated the wide distribution of STEC in ruminant herds, which represent an important reservoir for strains that pose a potential risk for human infections. 相似文献