北京地区仔猪大肠杆菌血清型鉴定及其毒力因子检测

本试验旨在调查北京地区仔猪腹泻的原因及猪源大肠杆菌血清型、毒力因子的分布情况。收集北京京郊地区仔猪腹泻样本400份,应用含2%血清的TSA培养基分离大肠杆菌,通过血清型鉴定试验和毒力因子检测验证O抗原。结果显示,400份样本中分离到64株大肠杆菌,定型42株。其主要为O101型（18.7%）、O64型（12.5%）、O8型（10.9%）、O20型（10.9%）、O45型（4.7%）、O149型（4.7%）、O2型（1.6%）、O89型（1.6%）8种血清型,其携带的毒力因子为STa、Stx2e、astA和eaeA等。结果表明,引起京郊仔猪腹泻的大肠杆菌主要有8个血清型,其中O101型发病比例最高。其携带的毒力因子主要为astA和eaeA,占全部菌株的50%以上,STa和Stx2e因子占全部菌株的30%以上。本试验结果将为今后京郊地区仔猪腹泻病的防控提供有效的数据支持。     

Detection of Serotypes and Virulence Factors of Escherichia coli from Piglets in Beijing

To investigate the cause of piglets diarrhea, and the distribution of the serotype and virulence factors of swine Escherichia coli in Beijing, 400 diarrhea samples were collected. TSA serum agar culture method was used to isolate Escherichia coli, serotype identification test and virulence factor genes test were used to verify the presence of O-antigen. 64 strains of E.coli were isolated from 400 diarrhea samples, among which 42 strains of E.coli were classified as 8 serotypes:O101(18.7%),O64(12.5%),O8(10.9%),O20(10.9%),O45(4.7%),O149(4.7%),O2(1.6%) and O89(1.6%), and the major virulence factors were STa, Stx2e, astA and eaeA. There were 8 mainly serotypes that caused piglets diarrhea in Beijing area, among which O101 serotype accounted for the highest proportion. The major virulence factors were astA and eaeA, accounted for more than 50% of all strains, STa and Stx2e accounted for more than 30% of all strains. These data would provide effective data to support the prevention and control of piglet diarrhea in Beijing.     

猪流行性腹泻病毒变异株XP2018的分离及S基因序列分析

本研究旨在从临床仔猪腹泻样品中分离猪流行性腹泻病毒(PEDV),并对其S基因进行测序分析.对腹泻仔猪小肠样品进行RT-PCR检测、病毒的分离培养、RT-PCR和间接免疫荧光鉴定、S基因测序及遗传演化分析.结果显示:仔猪腹泻由流行性腹泻病毒引起;在Vero细胞上成功分离流行性腹泻病毒,命名为XP2018,该毒株细胞病变明...     

Dilemma of virulence of Streptococcus suis: Canadian isolate 89-1591 characterized as a virulent strain using a standardized experimental model in pigs

Virulence of Streptococccus suis capsular type 2 strain 89-1591 has been controversial in literature. A standardized experimental model with specific-pathogen free piglets was used for a new evaluation of this strain. Twenty-nine piglets were allotted in 4 separated groups. Group 1 consisted of negative control animals which received broth medium. Groups 2, 3, and 4 were intravenously challenged with 2 mL of S. suis, strains 1330, 89-1591, and 166', respectively. The strain 1330 is a recognized avirulent Canadian strain. The strain 166' is a reference French virulent isolate. Pigs inoculated with strain 1330 did not present clinical signs of a S. suis infection. Contamination in organs and bacterial blood circulation were rare and lesions were almost non-existent. Infection of pigs with S. suis strain 89-1591 (group 3) and 166' (group 4) caused severe clinical problems, animals infected with S. suis 166' were the most affected. Pigs presented with clinical signs such as high body temperature, lameness, nervous symptoms, and even mortality. Lesions associated with S. suis were numerous for both strains, but more evident in animals of group 4. It can be concluded that S. suis strain 89-1591 is virulent, although its virulence seems to be lower than that of the French strain. Results of an experimental infection with strain 89-1591 may depend on different factors such as the route of inoculation and the immunological status of the animals used. Using conventional animals, with an unknown status regarding previous S. suis infections, equivocal results may be obtained, and this may explain differences reported by some authors with the same strain.     

仔猪腹泻致病性大肠杆菌分型鉴定及耐药性分析

为了解贵州省规模化养猪场腹泻仔猪致病性大肠杆菌流行情况及耐药性变化,本研究运用凝集试验、PCR和药敏纸片琼脂扩散法等方法对分离的78株致病性大肠杆菌进行血清型、毒力基因及耐药性分析。结果显示,78株致病性大肠杆菌以O138、O87血清型为主,占定型菌株的60.8%;其中62株致病性大肠杆菌检出毒力基因,检出率为79.5%,可分为8种毒力基因类型,分属肠致病性大肠杆菌（EPEC）、肠产毒性大肠杆菌（ETEC）和肠聚集性大肠杆菌（EAEC）,毒力基因eaeA、elt和escV检出率较高,分别为38.5%、28.2%和21.8%;分离到的致病性大肠杆菌对β-内酰胺类药物高度耐药,均为多重耐药株,耐药种类可达8种以上。结果表明,当前贵州省规模化养猪场腹泻仔猪致病性大肠杆菌的毒力基因检出率较高且基因型复杂,耐药性严重。本试验结果可为规模化养猪场防控仔猪腹泻提供基础资料及理论依据。     

Study of antigenic heterogeneity among Actinobacillus pleuropneumoniae serotype 7 strains

Actinobacillus pleuropneumoniae serotype 7 strains were studied for their antigenic heterogeneity using rabbit polyclonal hyperimmune sera against all the known twelve reference strains of A. pleuropneumoniae and a battery of different serological tests such as coagglutination (COA), immunodiffusion (ID), indirect hemagglutination (IHA), counterimmunoelectrophoresis (CIE), rapid dot-ELISA (RDE), serum soft-agar (SSA) and growth agglutination (GA). Reference serotype 7 strain (WF83) showed cross-reactivity with reference serotype 1B strain but not with other serotypes. Field serotype 7 strains showed cross-reactivities with serotypes 1A, 1B, 4, 9, 10, and 11 in COA, ID, and CIE tests, but not in IHA test. Two field strains of serotype 7 (90-3182 and 86-1411) which appeared to be different from the typical serotype 7 strains were selected for further antigenic characterization by SDS-PAGE, Western blot, and Tricine SDS-PAGE assays, and identified as serotypes 1 and 7, respectively. For serotyping atypical strains, it is suggested to use Western blot assay as a confirmatory test to identify serotype-specific capsular and somatic antigens.     

1株多杀性巴氏杆菌的全基因组序列及致病相关基因分析

通过对多杀性巴氏杆菌(Pasteurella multocida)CS株全基因组的毒力基因分析,以期从基因组角度了解P. multocida CS的致病性机理。常规方法分离细菌,并进行毒力鉴定。基于二代测序平台对P. multocida CS进行测序,应用比较基因组学方法将其与GenBank中具全基因组来源于不同地域和宿主的P. multocida基因组进行比较分析。结果显示：猪肺疫病料中分离细菌滴鼻感染小鼠,测得其LD₅₀为5×10² CFU·mL^-1,显示较强毒性。将测序后的P.multocida CS株全基因组信息提交至NCBI,获得登录号SUB11119617。通过对P.multocida CS全基因组序列的分析表明,P.multocida CS株全基因组大小为2 599 048 bp,G+C含量为39.932%,编码CDs为2 580个,占整个基因组长度的69.6%,编码CDs的平均长度为952 bp。此外还有53个tRNA基因和3个rRNA基因。有87.95% 的编码CDs可进行COGs功能分类,29个为功能未知基因。利用RaAXML的最大释然法(maximum likelihood,ML)进行系统进化分析发现,P. multocida CS株与1个猪源性、2个牛源血清A型毒株,和1个猪源性D型毒株有较近的亲缘关系。P. multocida CS株含254个毒力相关基因,分为4大类11小类。其中铁摄取系统、黏附系统、分泌系统和双组分调控系统相关的多个基因在不同的毒株(包括血清型)的分布存在多态性。通过对基因出现频率的分析发现,铁摄取系统相关的tbpA和铁复合物外膜受体蛋白基因(iron complex outer membrane receptor protein gene,irp)以及黏附的相关的ppdD和ompA基因在血清A型出现的频率较高,这是否与不同菌株的毒力差异相关有待进一步证实。P. multocida CS的分泌系统由Ⅰ型(hly基因)、Tat型、Sec-SRP型3种类型组成。其中,hlyD基因在不同的血清型的分布频率存在多态性。P. multocida CS株的双组分信号转导系统(TCSs)由16个调节相关基因,12个感应相关基因和2个有hybrid相关基因。这些基因在不同血清型分布的多态性与不同菌株毒力的关系有待进一步研究。综上所述,组成铁摄取系统、黏附系统、分泌系统和双组分调控系统的基因在不同的血清以及同一血清型内出现频率存在多态性,它们与P. multocida菌株毒力强弱的关系有待进一步研究。     

副猪嗜血杆菌小鼠毒力和仔猪毒力的相关性分析

旨在对我国最为流行的血清4、5、12和13型副猪嗜血杆菌（Haemophilus parasuis， HPS）（共36株）进行BALB/c小鼠和仔猪毒力试验的比较研究。小鼠毒力试验结果表明，4种血清型菌株的LD₅₀分别介于9.80×10⁷~4.60×10⁹、2.10×10⁸~8.85×10⁹、4.81×10⁷~7.01×10⁹和1.75×10⁸~8.45×10⁸ CFU；整体毒力表现强弱依次是13、4、12、5型，但仅在5型与13型菌株之间毒力具有显著差异（P<0.05）。仔猪毒力试验结果表明，同一血清型中不同菌株的毒力具有明显差异，均存在强毒和弱毒菌株；整体毒力表现强弱依次是5、13、4、12型；但5型与4型（P=0.039）和12型（P=0.033）之间具有显著差异（P<0.05），与13型差异不显著（P=0.241）。综合对比分析HPS的小鼠和仔猪毒力试验结果，可以得出3个结论：1）4种国内流行性血清型菌株的整体毒力由强到弱依次是5、13、4和12型；2）但同一血清型中均存在强毒和弱毒菌株，HPS的血清型与其毒力之间不具有相关性；3） HPS虽能致死BALB/c小鼠，但其毒力结果与仔猪毒力试验结果并不一致，表明其作为替代模型具有一定的缺陷。     

Morphometric analysis of enteric lesions in C3H/HeN mice inoculated with Serpulina hyodysenteriae serotypes 2 and 4 with or without oral streptomycin pretreatment.

The segmental distribution and sequential progression and the role of the indigenous bacterial flora in the development of enteric lesions associated with Serpulina hyodysenteriae infection in laboratory mice have not been defined. We examined the distribution and sequential morphometric changes in the large intestine of mice orally inoculated with S. hyodysenteriae serotypes 2 and 4. To determine the role of colonization resistance conferred by the indigenous bacterial flora, 40 female C3H/HeN mice were administered water alone or water containing 5 mg/mL streptomycin sulfate ad libitum for seven days prior to orogastric inoculation either with S. hyodysenteriae or sterile trypticase soy broth (TSB). Clinical signs were monitored daily and three mice per group were necropsied on postinoculation days (PID) 7 and 14 for pathological assessment of the cecum, proximal colon, transverse colon, and descending colon, and bacteriological culture of the cecum for S. hyodysenteriae. Weekly pooled fecal samples were collected from each group for determination of total numbers of anaerobe bacteria. Gross examination revealed soft fecal pellets on PID 7 and 14 and catarrhal typhlitis on PID 14, irrespective of streptomycin pretreatment. The recovery rates of S. hyodysenteriae from the ceca of serotype 2- and serotype 4-inoculated mice was 100 and 91.7%, respectively. Statistically significant differences in morphometric changes between TSB- and S. hyodysenteriae-inoculated mice were present on PID 7 and 14 and were restricted to the cecum. Although oral administration of streptomycin for seven days prior to S. hyodysenteriae inoculation resulted in a significant reduction in the numbers of fecal anaerobes, it did not affect the colonization, distribution, severity, or progression of cecal lesions.     

Genomic relatedness among reference strains of different Streptococcus suis serotypes.

Hybridization studies using genomic DNA and a rDNA probe revealed genetic relatedness among reference strains of different Streptococcus suis serotypes. Although most serotype 22 isolates are biochemically atypical, the reference strain of capsular type 22 is genetically related to other S. suis serotypes, but not to Streptococcus pneumoniae. Using DNA digested with BamHI and BglII for ribotyping, some S. suis reference strains had common patterns, but this analysis mainly revealed variations in patterns of S. suis strains of different serotypes.     

猪流行性腹泻病毒分离鉴定及其灭活疫苗免疫保护效果研究

为筛选能用于猪流行性腹泻病毒(PEDV)疫苗研发的流行毒株,收集PEDV阳性病料,以Vero细胞进行病毒分离试验,并对分离毒株进行外源病毒检测、病毒培养特性研究、仔猪毒力试验及免疫效力试验等。9份PEDV阳性病料共分离到3株病毒,分别命名为PEDV-SC12、PEDV-JS12、PEDV-JX12。其中PEDV-SC12株存在支原体污染;PEDV-JS12株与PEDV-JX12株均能被PEDV特异性阳性血清中和;PEDV-JS12株能在Vero细胞上增殖并产生细胞病变,但适应细胞45代以后病毒培养效价仍然偏低;PEDV-JX12滴度能维持在106.0 TCID50/mL以上。PEDV-JX12株毒力试验显示,该分离株能够通过人工感染复制出腹泻病例,并能从发病动物体内检测到感染的病毒。免疫攻毒保护试验显示,以PEDV-JX12株制备的灭活疫苗免疫母猪,对所产仔猪攻毒后免疫组6.25%(1/16)发病,对照组100%(8/8)发病。说明PEDV-JX12株能够适应细胞培养,免疫接种母猪能给仔猪提供有效保护,可以用于PEDV流行毒株的疫苗研发。     

不同毒力猪繁殖与呼吸综合征病毒对仔猪肺和外周免疫器官损伤的研究

为研究不同毒力的PRRSV对仔猪肺脏和外周免疫器官损伤的差异,本实验分别采用PRRSV变异株(HuN4株)和PRRSV经典株(CH-1a株)感染35日龄健康的断奶仔猪,并在感染后0 d、3 d、7 d、10 d和14 d各迫杀3头,检测肺、颌下淋巴结、肠系淋巴结、腹股沟淋巴结、扁桃体和脾脏的病毒载量及病理变化情况,同时检测血清中抗PRRSV的抗体水平。结果表明:感染后3 d肺脏及各免疫器官可检测到病毒,HuN4感染组病毒载量比CH-1a感染组病毒载量高1 000倍;HuN4感染组病毒载量峰值出现在感染后10 d,而CH-1a感染组维持着较低水平的病毒载量。组织病理学检测显示HuN4感染组淋巴结内淋巴细胞显著减少,呈空泡状;CH-1a感染组淋巴结内淋巴细胞轻度减少,呈星隙状。本实验表明HuN4株比CH-1a株对肺和外周免疫器官造成更严重的损伤。     

Comparison in gnotobiotic pigs of lesions caused by verotoxigenic and non-verotoxigenic Escherichia coli

To compare the pathogenesis of calf and rabbit strains of E. coli, gnotobiotic pigs were infected with 10(10) colony forming units (cfu) of verotoxigenic strain RDEC-1 or S102-9, or a non-verotoxigenic E. coli (X114/83). Pigs were killed 4 days later, and intestinal tissue was fixed and examined by light, scanning, and transmission electron microscopy. Strains S102-9 and RDEC-1 caused diarrhea, attached to enterocytes, and effaced microvilli, confirming that the calf and rabbit strains possessed similar mechanisms of pathogenicity. Non-verotoxigenic strain X114/83 did not cause diarrhea, but in 5/5 piglets it was detected in histological sections adherent to enterocyte surfaces. Exfoliated enterocytes were seen in 4/5. Bacteria attached to enterocytes by "cups" and "pedestals," with effacement of microvilli, were seen by electron microscopy in 1/5 piglets. It was concluded that strain S102-9 appears to be an animal equivalent of human enterohemorrhagic E. coli, that verotoxin is not essential in the pathogenesis of attaching and effacing lesions, and that the lesions induced by S102-9 are more severe in gnotobiotic pigs than in gnotobiotic or conventional calves.     

The distribution of bmpB, a gene encoding a 29.7 kDa lipoprotein with homology to MetQ, in Brachyspira hyodysenteriae and related species

The distribution of the bmpB gene encoding BmpB, a 29.7 kDa outer membrane lipoprotein of the intestinal spirochaete Brachyspira hyodysenteriae, was investigated. Using PCR, the gene was detected in all the 48 strains of B. hyodysenteriae examined and in Brachyspira innocens strain B256T, but not in 11 other strains of B. innocens nor in 42 strains of other Brachyspira spp. The gene was sequenced from B. innocens strain B256T and from 11 strains of B. hyodysenteriae. The B. hyodysenteriae genes shared 97.9-100% nucleotide sequence similarity and had 97.5-99.5% similarity with the gene of B. innocens strain B256T. Southern hybridisation indicated that bmpB was present on a 1.9 kb HindIII fragment of the B. hyodysenteriae genome and on a 3.1 kb fragment of the B. innocens B256T genome. The B. innocens lipoprotein did not react in Western blots with monoclonal antibody BJL/SH1 that reacts with the B. hyodysenteriae lipoprotein. The difference in binding with the monoclonal antibody may reside in the replacement of a serine residue with a tyrosine residue at base position 210 in the lipoprotein from B. innocens B256T. Comparison of the BmpB amino acid sequence with sequences in the SWISS-PROT protein database indicated that it has 33.9-39.9% similarity with the d-methionine binding proteins (MetQ) of a number of pathogenic bacterial species. The bmpB gene was confirmed to be the same as a gene of B. hyodysenteriae that was recently designated "blpA".     

Identification of genes associated with prophage-like gene transfer agents in the pathogenic intestinal spirochaetes Brachyspira hyodysenteriae, Brachyspira pilosicoli and Brachyspira intermedia

VSH-1 is an unusual prophage-like gene transfer agent (GTA) that has been described in the intestinal spirochaete Brachyspira hyodysenteriae. The GTA does not self-propagate, but it assembles into a virus-like particle and transfers random 7.5kb fragments of host DNA to other B. hyodysenteriae cells. To date the GTA VSH-1 has only been analysed in B. hyodysenteriae strain B204, in which 11 late function genes encoding prophage capsid, tail and lysis elements have been described. The aim of the current study was to look for these 11 genes in the near-complete genomes of B. hyodysenteriae WA1, B. pilosicoli 95/1000 and B. intermedia HB60. All 11 genes were found in the three new strains. The GTA genes in WA1 and 95/1000 were contiguous, whilst some of those in HB60 were not-although in all three strains some gene rearrangements were present. A new predicted open reading frame with potential functional importance was found in a consistent position associated with all four GTAs, located between the genes for head protein Hvp24 and tail protein Hvp53, overlapping with the hvp24 sequence. Differences in the nucleotide and predicted amino acid sequences of the GTA genes in the spirochaete strains were consistent with the overall genetic distances between the strains. Hence the GTAs in the two B. hyodysenteriae strains were considered to be strain specific variants, and were designated GTA/Bh-B204 and GTA/Bh-WA1 respectively. The GTAs in the strains of B. intermedia and B. pilosicoli were designated GTA/Bint-HB60 and GTA/Bp-95/1000 respectively. Further work is required to determine the extent to which these GTAs can transfer host genes between different Brachyspira species and strains.     

Demonstration of genes encoding virulence and virulence life-style factors in Brachyspira spp. isolates from pigs

The distribution of many genes encoding virulence and virulence life-style (VL-S) factors in Brachyspira (B.) hyodysenteriae and other Brachyspira species are largely unknown. Their knowledge is essential e.g. for the improvement of diagnostic methods targeting the detection and differentiation of the species. Thus 121 German Brachyspira field isolates from diarrhoeic pigs were characterized down to the species level by restriction fragment length polymorphism analysis of the nox gene and subsequently subjected to polymerase chain reaction detecting VL-S genes for inner (clpX) and outer membrane proteins (OMPs: bhlp16, bhlp17.6, bhlp29.7, bhmp39f, bhmp39h), hemolysins (hlyA/ACP, tlyA), iron metabolism (ftnA, bitC), and aerotolerance (nox). For comparison, B. hyodysenteriae reference strains from the USA (n=7) and Australia (2) were used. Of all genes tested only nox was detected in all isolates. The simultaneous presence of both the tlyA and hlyA/ACP was restricted to the species B. hyodysenteriae. The hlyA infrequently occurred also in weakly hemolytic Brachyspira. Similarly to tlyA and hlyA all B. hyodysenteriae strains contained the ferritin gene ftnA which was also found in two Brachyspira intermedia isolates. OMP encoding genes were present in B. hyodysenteriae field isolates in rates of 0% (bhlp17.6, bhmp39h), 58.1% (bhlp29.7), and 97.3% (bhmp39f). Since the study revealed a high genetic heterogeneity among German B. hyodysenteriae field isolates differentiating them from USA as well as Australian strains, targets for diagnostic PCR were limited to the nox gene (genus specific PCR) as well as to the species specific nox(hyo) gene and the combination of hlyA and tlyA which allow to specifically detect B. hyodysenteriae.     

Detection of porcine epidemic diarrhea virus using polymerase chain reaction and comparison of the nucleocapsid protein genes among strains of the virus.

Two pairs of PCR primers were designed to perform nested PCR targetting of a 540 bp fragment of the nucleocapsid (N) protein gene (N gene) of porcine epidemic diarrhea virus (PEDV). The N gene of PEDV was amplified with 4 PEDV strains and 11 small intestines of PEDV-infected piglets collected from 2 farms in Kagoshima prefecture, Japan. Nucleotide sequences of the PCR products from a Korean and two Japanese strains (KKN96-1 and S1) of PEDV isolated in 1993 and 1996, respectively, were almost identical. These results suggest that the PCR is an available tool for detection of PEDV from pigs in the field, and that the two Japanese strains (KKN96-1 and S1) were genetically similar to the Korean strain.     

Characterization of Serpulina hyodysenteriae isolates of serotypes 8 and 9 from Quebec by restriction endonuclease fingerprinting and ribotyping.

This study was undertaken to assess the discriminatory value of restriction endonuclease fingerprinting (REF) analysis and ribotyping of 21 Serpulina hyodysenteriae isolates of serotypes 8 and 9. For REF analysis, DNAs were digested with the BglII restriction enzyme and the resultant fragments were separated by polyacrylamide gel electrophoresis. For ribotyping, hybridization of BglII genomic fragments with a probe of rrnB operon using an Escherichia coli rDNA probe was performed on all isolates. Although many isolates shared a common pattern by BglII REF and BglII ribotyping analysis, differences among some S. hyodysenteriae isolates were observed. REF and ribotyping using BglII restriction enzyme, were not specific for serotypes. The predominance of an REF and a ribotype pattern among S. hyodysenteriae isolates from Quebec suggested that epidemiologically important S. hyodysenteriae types occur in different swine herds.     

Serotypes,Virulence Factors and Antibiotic Resistance of Duck Pathogenic Escherichia coli in Jiangsu Province and Its Surrounding Areas

In this study,191 strains of avian pathogenic Escherichia coli (APEC) were isolated from duck farms in and around Jiangsu province.The serotype,virulence gene distribution and drug resistance of 21 strains (one from each farm) were detected,and the correlation between serotype,virulence gene distribution and drug resistance was analyzed,in order to provide reference for the prevention and control of APEC.The serotypes of 21 APEC strains showed that there were 12 strains of O65,accounting for 57.14% of all strains.The results of virulence gene detection showed that 5 virulence genes had a high distribution rate,among which the positive rate of fimA gene was 100%,and the positive rates of ECs3737,ECs3703,tsh and irp2 genes were 90.5%,85.7%,57.1% and 42.9%,respectively.There were 6 strains (28.57%) with five virulence genes.The results of drug sensitivity test showed that 21 APEC strains had multiple drug resistance,and 100% strains were resistant to enrofloxacin,doxycycline,vancomycin and erythromycin.Among all the strains,85.71% and 14.29% were resistant to more than 10 and 21 kinds of drugs,respectively.The relationship among serotypes,virulence gene distribution and drug resistance showed that there were 13 strains with more than 4 virulence genes,9 of which were O65 serotypes.Among the 13 strains with more than 4 virulence genes,9 strains (69.23%) were resistant to more than 15 drugs,and 3 strains (23.08%) were resistant to more than 20 drugs.The results showed that the serotypes of Escherichia coli isolated from ducks in Jiangsu province and its surrounding areas were complex,carrying a variety of virulence genes,and the drug resistance was serious.     

江苏及周边地区鸭致病性大肠杆菌血清型、毒力因子及耐药研究

本研究旨在明确江苏及周边地区鸭禽致病性大肠杆菌（avian pathogenic Escherichia coli,APEC）的血清型、毒力基因分布和耐药性之间的相关性,以期为APEC的防控提供依据。从江苏省及周边养鸭场分离了191株APEC,并对其中21株（每个养殖场选取1株）的O抗原血清型、毒力基因分布和耐药性进行检测。对21株APEC的血清型检测结果表明,O65血清型12株,占全部菌株的57.14%,O5、O28、O42、O87、O93、O138、O147血清型均为1株,其他血清型2株;毒力基因检测结果表明,5个毒力基因有较高的分布率,其中fimA基因的阳性率为100%,ECs3737、ECs3703、tsh和irp2基因的阳性率分别为90.5%、85.7%、57.1%和42.9%,含有5个毒力基因的菌株共有6株（28.57%）;药敏试验结果表明,21株APEC均存在多重耐药性,100%的分离菌株对恩诺沙星、强力霉素、万古霉素和红霉素耐药,85.71%的分离株对10种以上抗生素耐药,14.29%的菌株对21种药物都耐药;对血清型、毒力基因分布和耐药性之间的关系分析表明,含有4种以上毒力基因的菌株有13株,其中9株是O65血清型。在13株含有4种以上毒力基因的菌株中,耐15种药物以上的有9株（69.23%）,耐20种以上药物的有3株（23.08%）,表明含有4种以上毒力基因的菌株多重耐药现象严重。研究表明,江苏及周边地区鸭源大肠杆菌血清型复杂,携带多种毒力基因,耐药性严重。