海安县猪水肿病的流行病学与病原特性研究

对江苏省海安县2003年5月-2004年5月各乡镇猪水肿病的发病和死亡情况进行了流行病学调查,发现猪水肿病在该地区呈零星散发性发生,发病率为0.31%～1.84%,死亡率为0.07%～0.56%,病死率为16.0%～35.0%。水肿病主要侵害仔猪,育成猪也偶有发生,一般以气温比较高的季节多发。同时从疑似猪水肿病的病料中分离到12株大肠杆菌,经O血清型鉴定,5株为O139,2株为O45,O55、O93、O9、O101、O119各1株。经多重PCR检测毒素基因(STa、STb、LT、SLT-2e)和大肠杆菌粘附素单抗(F4、F5、F6、F41、F18)检测菌毛,共6个分离株带有SLT-2e基因,其中O139分离株5株,O55分离株1株,其余6株均带STb基因。12个分离株中,单独表达F18菌毛的4株(O1392株,O45、O119各1株),F5 F411株(O93),F41 F181株(O139),F5 F41 F182株(均为O139)。经药敏试验,多数分离菌株对壮观霉素和新霉素高度敏感。     

上海地区猪源大肠杆菌血清型及其毒力因子分布调查

对上海地区分离的199株猪源大肠杆菌分离株进行血清型鉴定和毒力因子检测,使用大肠杆菌标准抗O因子血清进行玻片凝集试验;采用普通和多重PCR方法,对分离株进行STa、STb、LT、Stx2e等4种肠毒素和K88、K99、987P、F18、F41等5种黏附素检测。结果:199株猪源大肠杆菌分离株有110株鉴定出血清型,占检测菌株的55.28%,覆盖了30种血清型,优势血清型为O8、O45、O64、O78、O138、O157、O163、O7+O8,占定型菌株的60%。共有32株大肠杆菌检测到毒力因子,阳性率为16.08%,检测出9种毒力因子。其中有21株单独检测到肠毒素,占65.63%,STa和STb+LT阳性的菌株分别为14和4;6株单独检测到黏附素,3株菌株K99阳性;5株同时检测到肠毒素和黏附素。在32株毒力基因阳性的大肠杆菌中,有15株血清型定型,覆盖7种血清型,其中O138、O7+O8与肠毒素STa相关,O8、O45与STb+LT相关。研究表明,上海地区猪源大肠杆菌分离株优势血清型至少覆盖了包括O8、O45、O64、O78、O138、O163等在内的8种血清型;大肠杆菌分离株以产肠毒素为主,主要毒力因子包括黏附素K99和肠毒素STa、STb+LT等。     

海安县猪水肿病的流行病学与病原特性研究

对江苏省海安县2003年5月～2004年5月各乡镇猪水肿病的发病和死亡情况进行了流行病学调查，发现猪水肿病在海安地区呈零星散发性发生，发病率为0.31％～1．84％，死亡率为0．07％—0．56％，病死率为16．0％～35．0％。水肿病主要侵害仔猪，育成猪也偶有发生，一般以气温比较高的季节多发。同时从疑似猪水肿病的病料中分离到12株大肠杆菌，经O血清型鉴定，5株为0139，2株为O45，O55、O93，O9、O101、O119各1株。经多重PCR检测毒素基因(STa，STb、LT、SLT-2e)和大肠杆菌粘附素单抗(F4、F5、F6、F41、F18)检测茵毛，共6个分离株带有SLT-2e基因，其中O139分离株5株，055分离株1株，其余6株均带STb基因。12个分离株中，单独表达F18菌毛的4株(O1392株，O45、O119各1株)，F5 F411株(O93)，F41 F181株(O139)，F5 F41 F182株(均为O139)。经药敏试验，多数分离株对壮观霉素和新霉素高度敏感。     

猪大肠埃希菌分离鉴定及毒力因子PCR检测

为了解陕西省宁强县部分地区引起仔猪黄白痢的致病性大肠埃希菌的主要血清型及其主要毒力因子,用细菌分离培养方法,从宁强县5个猪场采集的60份有疑似黄白痢症状仔猪的肛门拭子中分离出20个大肠埃希菌菌株。经菌落形态观察、革兰染色镜检、培养特性、生化试验、血清型鉴定,确定分离菌株均为致病性大肠埃希菌。血清分型表明,20个分离菌株中有18株能确定血清型,分布在7个血清型中,其中优势血清型为O8(8株),占总数的40%。药物敏感性试验表明,分离菌株对临床常用药物具有抗药性。毒力因子的PCR检测结果表明,分离菌株均不携带STa、STb、LT和SLT-2e四个毒力基因。     

猪水肿病大肠杆菌分离、鉴定及药敏试验

本实验从疑似猪水肿病的病例分离到5株大肠杆菌,O抗原鉴定结果表明所有菌株均为O139血清型;应用F18ab菌毛单克隆抗体对这5株大肠杆菌能否表达F18ab菌毛进行了鉴定,结果表明其中2个菌株能表达F18ab菌毛;利用聚合酶链式反应(PCR)对志贺氏菌样毒素Ⅱ型变异体(SLT-Ⅱe)操纵子基因保守区进行了扩增,结果发现在能表达F18ab菌毛2个菌株中可扩增一段特异性序列。以上数据表明这2株大肠杆菌为致仔猪水肿病大肠杆菌。药敏试验表明这两株菌株均对氟哌酸、妥布霉素、庆大霉素、利福平等抗生素高度敏感。     

西藏林芝地区仔猪白痢血清型及毒力基因检测

为探究西藏林芝地区仔猪白痢大肠杆菌优势血清型和毒力基因间的相关性,采用玻片凝集试验测定与仔猪白痢有关的血清型,PCR方法调查11种毒力基因。结果显示,在分离的81株藏猪源大肠杆菌里有72株检测到毒力基因,其中黏附素K88和CS31A分别检测到1(1.39%)和34(47.22%)株;肠毒素STa、STb和EAST1分别检测到10(13.89%),16(22.22%)和38(52.78%)株;毒力岛eaeA、irp2和ETT2分别检测到12(16.57%),44(61.11%)和56(77.78%)株。72株中有59株鉴定出9种血清型,其中有15株定型为O8(20.99%),11株定型为O64(16.05%),10株定型为O138(13.58%)。研究表明:O8、O64、O138为优势血清型,且O8与STa+STb相关,O107与肠毒素STa相关,O64与毒力岛eaeA+ETT2有关,毒力基因以EAST1+CS31A+irp2+ETT2组合检出率最高为18(25%)株。     

黑龙江地区断奶仔猪腹泻大肠杆菌种系类群、血清型和毒力基因分析

揭示黑龙江地区集约化猪场仔猪断奶腹泻(PWD)直肠棉拭子分离到的123株大肠埃希菌所属种系分类群、O血清型及其与毒力基因的特征.采用常规凝集试验进行测定,种系分类群标记的ch uA、yjaA基因和TSPE4.C2DNA片段及肠毒素基因STa、STb、LT、SL T-2e采用PCR方法检测.在123株分离菌株中,除21株未定型、10株自凝外,测定出92株分离的血清型,覆盖18个血清型,其中以O8、O 9、O 149 3种血清型为主,共57株,占定型菌株的61.96％.环境共生的种系进化A群113株占91.87％,肠外强致病D种系进化群2株占1.63％.肠毒素检出菌株74,占分离株的60.16％,其中以STa、STb为主,共占肠毒素检出株的94.59％.结果显示黑龙江省PWD病原性大肠埃希菌优势血清型为O 8、O9、O149,大肠埃希菌肠毒素主要毒力因子为STa、STb,种系进化群为A.     

海安县猪水肿病的流行病学调查

对江苏省海安县2003年各乡镇猪水肿病的发病和死亡情况进行了流行病学调查，发现猪水肿病在海安地区呈零星散发，发病率为0．29％～1．36％，死亡率为0．08％～0．35％。从疑似猪水肿病的病料中分离到22株大肠埃希氏茵，其中12株经血清型鉴定，O139 5株，O15 2株，O55、O93、O9、O101、O119各1株。经多重PCR检测毒素基因和黏附素单抗检测菌毛，发现6个分离株带有SLT-Ⅱe基因，其余6株带有STb基因。单独表达F18茵毛的4株，F5 F41的1株，F41 F18的1株。F5 F41 F18的2株。药敏试验结果表明，多数分离株对恩诺沙星、庆大霉素、阿米卡星和壮观霉素高度敏感。     

致断奶仔猪腹泻、水肿病大肠杆菌F18菌毛a因子单克隆抗体的研制及其初步应用

以表达 F18ac菌毛参考菌株 2 134(O15 7∶ H19)为研究对象 ,摸索出了 F18ac菌毛表达的最佳条件 ,采用热洗脱法获得了较纯的 F18ac菌毛 ,并以之免疫小鼠 ,利用淋巴细胞杂交瘤技术 ,用直接玻板凝集法筛选出 1株杂交瘤细胞株 19B4 ,能稳定分泌针对 F18ac菌毛和 F18ab菌毛共同抗原表位 a因子的单克隆抗体。细胞培养上清对 F18ac菌毛参考菌株 2 134和 F18ab菌毛参考菌株 10 7/ 86的直接凝集价均可达 1∶ 8,腹水单抗直接凝集效价可达 1∶ 10 2 4 ,而与猪源产 F4、F5、F6和 F4 1粘附素大肠杆菌菌株、鸡源产 型菌毛大肠杆菌菌株及沙门氏菌不发生凝集反应。免疫印迹试验结果显示 ,腹水单抗可同时特异识别 F18ac菌毛 170 0 0和 F18ab菌毛 15 0 0 0左右的主要亚单位多肽。应用所研制的单抗对 2 15株断奶仔猪腹泻大肠杆菌分离株进行了检测 ,结果上述分离株 TSB培养物的 F18菌毛的检出率为13.4 % ,TSA培养物的检出率为 8.4 %。F18菌毛阳性分离株的 O血清型除了常见血清型 O139、O14 1外 ,还有非常见血清型 O10 7、O131和 O9等。TSB培养物的 F18菌毛检出率明显高于 TSA培养物的检出率 ,表明 F18菌毛在 TSB培养基中比在 TSA培养基上更容易表达 ,TSB培养基是适合 F18菌毛检测、流行病学调查的培养基     

皖北地区仔猪源大肠杆菌毒力因子及HPI毒力岛的检测

我国皖北地区哺乳仔猪腹泻频发,临床直肠棉拭子培养物有34例符合大肠杆菌特征,并进行产肠毒素大肠杆菌(ETEC)毒力因子(STa、STb、LT、SLT-2e)和HPI毒力岛的PCR快速检测。结果,仅有10例表达STa和STb(29.41%),其中3例表达STa基因(8.82%),2例表达STb基因(5.88%),2例表达STa和STb基因,1例表达STa和irp2基因(2.94%),2例表达STa和STb及irp2基因,揭示HPI+大肠杆菌与ETEC混合感染共有3例(8.82%);未检测到LT和STL-2e毒力因子。有10例表达irp2基因(29.41%),其中7例独立表达irp2基因(20.59%)。STa、STb和Irp2的PCR产物测序结果分别与GenBank检索的目标序列比对,其同源性均达到100%。结果初步揭示了皖北地区致哺乳仔猪腹泻ETEC毒力因子及HPI毒力岛的分布情况。     

Prevalence of the enteroaggregative Escherichia coli heat-stable enterotoxin 1 gene and its relationship with fimbrial and enterotoxin genes in E. coli isolated from diarrheic piglets.

A total of 720 Escherichia coli strains isolated from diarrheic piglets on 756 swine farms were screened for the presence of the enteroaggregative E. coli heat-stable enterotoxin 1 (EAST1) gene by polymerase chain reaction (PCR). Escherichia coli strains that carried EAST1 genes were also tested by PCR for the presence of 4 fimbriae (F4, F5, F6, F41), 2 heat-stable enterotoxins (STa and STb), and 1 heat-labile enterotoxin (LT) gene. One hundred sixty-four (22.7%) of the 720 E. coli isolates carried genes for EAST1. Of these 164 isolates, 62 (37.8%) carried EAST1 genes only, 11 (6.7%) carried genes for at least 1 of the fimbrial adhesins, 51 (31.1%) carried genes for at least 1 of the enterotoxins, and 40 (23.8%) carried genes for at least 1 of the fimbrial adhesins and enterotoxins. Forty-six percent of strains that carried EAST1 genes carried STa genes, and 16% of strains that carried EAST1 genes carried F4. The isolation rate of enterotoxigenic E. coli strains carrying genes for EAST1 gene was 63%. The 6 major genotypes observed in this study (in decreasing order) were EAST1+, EAST1+STa+, EAST1+STa+STb+, EAST1+STa+F5+, EAST1+STa+F4+, and EAST1+STb+F4+. EAST1 is widely prevalent among diarrheagenic strains of E. coli and may represent an important virulence determinant in the pathogenesis of enteric colibacillosis of preweaned pigs.     

Virulence factors and genetic relatedness of Escherichia coli strains isolated from pigs with post-weaning diarrhea

Forty-six Escherichia coli strains isolated from post-weaning diarrhea of pigs were analysed for their phenotypic and genotypic properties. The isolates were of serogroups O138, O139, and O141 and most of them possessed hemolytic activities. PCR analysis showed that 34 of the isolates harboured the genes for shiga toxin 2e and 32 strains possessed the genes for heat-stable enterotoxins I and II. Ten strains had the fedA gene of F18 fimbriae. The genetic relationships among all isolates were tested by random amplified polymorphic DNA (RAPD) and enterobacterial repetitive intergenic consensus (ERIC) PCR analyses. Using the RAPD test with two different primers, six fingerprints were distinguished whereas the ERIC analysis revealed only three DNA patterns. Some strains possessing identical phenotypic and genotypic virulence determinants exhibited distinct RAPD profiles and some isolates with different pathogenic markers showed the same RAPD and ERIC pictures. Thus, RAPD, and to a less extent ERIC techniques, revealed intra- and interserogroup genotypic variations among the E. coli strains analyzed.     

Genotypic prevalence of the adhesin involved in diffuse adherence in Escherichia coli isolates in pre-weaned pigs with diarrhoea in Korea

A total of 1002 Escherichia coli strains isolated from pre-weaned pigs with diarrhoea on 1114 swine farms were screened for the presence of the adhesin involved in diffuse adherence (AIDA) gene by polymerase chain reaction (PCR). Escherichia coli isolates that carried AIDA genes were also tested by PCR for the detection of five fimbriae (F4, F5, F6, F18 and F41), heat-stable (STa, STb) and heat-labile (LT) enterotoxin, enteroaggregative E. coli heat-stable enterotoxin 1 (EAST1), and Shiga toxin 2 oedema disease (Stx2e) genes. Twenty-three (2.3%) of the 1002 E. coli isolates carried the gene for AIDA. Among 23 isolates shown to carry genes for AIDA, three carried the AIDA gene as the only shown virulence factor. Other isolates carried other virulence factor genes in addition to AIDA. Four isolates carried genes for at least one of the fimbrial adhesins and enterotoxins. Sixteen isolates carried genes for enterotoxins only. The AIDA may represent an additional virulence determinant in pre-weaned pigs with diarrhoea.     

Prevalence of the enteroaggregative Escherichia coli heat-stable enterotoxin 1 (EAST1) gene in isolates in weaned pigs with diarrhea and/or edema disease

A total of 476 Escherichia coli isolated from weaned pigs with diarrhea and/or edema disease were screened for the presence of the enteroaggregative E. coli heat-stable enterotoxin 1 (EAST1) gene by polymerase chain reaction (PCR). E. coli strains that carried EAST1 genes were also tested by PCR for the presence of genes for five fimbriae (F4, F5, F6, F18 and F41), two heat-stable (STa and STb) and one heat-labile (LT) enterotoxin, and Shiga toxin 2e (Stx2e). One hundred and forty nine (31.3%) of the 476 E. coli isolates carried the gene for EAST1. Of these 149 isolates, 66 (44.3%) carried the east1 gene only and 83 (55.7%) carried genes for the fimbrial adhesins or enterotoxins. E. coli which carried east1 gene also possessed genes for STa or F4 frequently. EAST1 may represent an additional determinant in the pathogenesis of E. coli diarrhea in weaned pigs.     

Enterotoxigenic Escherichia coli in the jejunum of piglets with neonatal diarrhea

Thirty-two Escherichia coli colonies were taken from the primary step of cultivation of the jejunal contents of each of 10 dead piglets which had suffered from diarrhea. The organisms of each colony were examined for the presence of adhesion fimbria (F4 (K88) and F5 (K99)), production of heat-stable and heat-labile enterotoxin and of colicins.The presence of heat-labile enterotoxin in the intestinal content of the necropsied pigs was also tested, and results correlated with enterotoxin production of the isolated E. coli strains. In all but 3 pigs, 50–80 % of the E. coli strains were found to produce one or both of the enterotoxins and to possess the F4 of the F5 antigen. All bacteria producing both heat-labile and heat-stable enterotoxin proved to belong toi O group 149 and to possess the F4 antigen. Strains from 1 pig belonged to O group 64 and possessed the F5 antigen; these bacteria produced heat-stable enterotoxin only. Most of the enterotoxin-producing E. coli also produced colicins.After each subcultivation, the strains produced less heat-labile enterotoxin, some becoming negative when assayed.     

仔猪黄痢病原分离株药敏试验和不同给药方法疗效比较研究

为科学评价河南省仔猪黄痢大肠杆菌地方分离株的耐药性和不同给药方法对仔猪黄痢疗效的影响,本研究首先自河南省25个临床发病猪场病猪体内分离鉴定仔猪黄痢大肠杆菌;通过小白鼠致病力试验以检测大肠杆菌分离株的毒力;采用20种抗菌药物对分离株进行药敏试验以筛选对仔猪黄痢大肠杆菌最敏感的药物;选取敏感药物分别采用口腔灌服、肌肉注射和腹腔注射3种给药方法对临床上仔猪黄痢发病猪进行治疗效果比较试验以确定最佳给药方法。结果自河南省25个发生仔猪黄痢的猪场的病猪体内共分离鉴定出25株大肠杆菌。25株大肠杆菌分离株对小白鼠的致病率为100%;对临床上常用的20种抗菌药物都有耐药现象,但耐药率高低不同(4%～100%);20种抗菌药物中诺氟沙星、氧氟沙星、新霉素和利福平等4种药物的敏感率较高,高敏率分别为92%、88%、88%和80%。3种不同的给药方法对仔猪黄痢病例的治疗效果不同,其中通过口腔灌服和腹腔注射的给药方法对仔猪黄痢的治愈率(分别为92.3%、95.0%)显著高于肌肉注射给药方法(58.8%);腹腔注射组治愈率稍高于口腔灌服组,但二者差异不显著。本研究为临床上仔猪黄痢的防制提供了科学依据。     

Distribution of virulence genes in Escherichia coli strains isolated from diarrhoeic piglets in the Slovak Republic

Ninety-two Escherichia coli isolates from 14 to 28-day-old piglets that died because of diarrhoea were examined for genes for fimbriae (F4, F5, F6, F18 and F41), enterotoxins (STa, STb and LT), verotoxin (VT2e or Stx2e) and enteroaggregative heat-stable enterotoxin 1 (EAST1) by polymerase chain reaction. Twenty-two strains (24%) carried a gene for F4, whereas genes for F18, F6 and F5 + F41 were detected in 10.8, 3.3 and 1.1% of strains respectively. Genes for STb, LT, STa and Stx2e were detected in 40.2, 26.1, 14.1 and 1.1% of strains respectively. The astA gene was detected in 49 (53.3%) isolates, 35 of which also carried genes for enterotoxins and/or fimbriae. The major genotypes reached at (in decreasing order of prevalence) were F4/STb/LT/EAST1, F18/STa/STb/EAST1, STb/EAST1, F6/STa/STb/EAST1 and F18/STb/EAST1.     

Virulence and fitness gene patterns of Shiga toxin-encoding Escherichia coli isolated from pigs with edema disease or diarrhea in Germany

Fecal Escherichia coli isolates (n = 3,218) from piglets with edema disease or diarrhea were screened for the genes of Stx2 and Stx2 variants. A total of 283 E. coli isolates (8.8%) proved exclusively positive for Stx2e and most of these (85.1%) harbored genes for F18 fimbria. No recognized adhesins were detectable in 14.5% of the isolates. Genes for heat-stable or heat-labile E. coli enterotoxins were found in F18+ as well as F18 isolates (51.9% and 33.3%, respectively). Five isolates also harbored fyuA and irp2 genes which are indicative of a high pathogenicity island in E. coli. All Stx2e+ isolates lacked genes for intimin, EHEC hemolysin, STEC autoagglutinating adhesin, subtilase cytotoxin, serine protease Espl. The majority of Stx2e+ isolates belonged to phylogenetic groups A (59.3%) and D (38.9%) and only few isolates were classified as B1 and B2 (1.8%). The results suggest that Stx2e-producing E. coli strains are highly prevalent in diseased pigs in Germany. Despite their significant diversity, most strains possess all typical features (Stx2e, F18) of porcine edema disease E. coli. However, a considerable portion of porcine strains resembles published human Stx2e+ strains in that they lack any recognized pig-associated adhesin. Thus, a zoonotic potential cannot be excluded for these strains.     

Prevalence of virulence genes in Escherichia coli strains recently isolated from young pigs with diarrhea in the US

Enterotoxigenic Escherichia coli (ETEC)-associated post-weaning diarrhea (PWD) is economically one of the most important diseases for the swine industry. Porcine ETEC strains typically express K88 or F18 fimbria and heat-labile (LT) and/or heat-stable (STa, STb) enterotoxins. However, recent studies indicate that EAST1 toxin, adhesin involved in diffuse adherence (AIDA-I) and porcine attaching and effacing-associated factor (paa) may also be expressed by ETEC strains associated with diarrhea. To better understand the virulence factors of E. coli strains that cause PWD, we applied PCR to screen for K88, F18, F41, 987P and K99 fimbrial genes; LT, STa, STb, Stx2e and EAST1 toxic genes; and AIDA-I, paa and EAE adhesin genes in E. coli strains recently isolated from young pigs with PWD in the US. Of 304 E. coli isolates from diarrheic pigs submitted for testing, 175 (57.6%) strains possessed fimbrial genes: K88 (64.6%), F18 (34.3%), F41 (0.57%), K99 (0.57%), 987P (0); toxin genes: LT (57.7%), STb (72.6%), STa (27.4%), STx2e (17.4%), EAST1 (35%); and adhesin genes: AIDA-I (26.9%), paa (60%), EAE (1.1%). All toxin genes except the EAST1 toxin gene, were almost exclusively associated with K88+ or F18+ isolates, and most of these isolates carried multiple toxin genes. The non-fimbrial adhesin paa was found present in over half of the K88+ isolates. A total of 129 (42%) isolates carried no fimbrial genes, including 66 (21.7%) isolates that did not have any of the above virulence genes. These results suggest a broad array of virulence genes associated with PWD in pigs.     

Isolation and association of Escherichia coli AIDA-I/STb, rather than EAST1 pathotype, with diarrhea in piglets and antibiotic sensitivity of isolates.

To identify emerging Escherichia coli that have the potential to cause diarrhea in pigs, the prevalence of E. coli pathotypes was determined among 170 and 120 isolates from diarrheic and nondiarrheic piglets, respectively. The isolates were tested for F4, F5, F6, F18, and F41 fimbriae, for E. coli attaching and effacing (EAE), porcine attaching and effacing-associated (Paa), and adhesin involved in diffuse adherence (AIDA-I) factors, for LT, STa, STb, and enteroaggregative heat-stable (EAST1) enterotoxins, and for Shiga toxins (Stxl, Stx2, and Stx2e), using DNA hybridization and polymerase chain reaction. All isolates were O-serotyped and tested for antibiotic resistance against 10 drugs. Seventeen different pathotypes, accounting for 40.0% of the isolates, were recovered from diarrheic piglets. The main pathotypes included EAST1 (13.5%), F4/LT/STb/EAST1 (6.5%), AIDA-I/STb/EAST1 (4.1%), F5/STa (2.9%), EAE/EAST1 (2.9%), and AIDA-I/F18 (2.3%). Only 3 pathotypes, EAE (11.7%), EAST1 (10.8%), and EAE/EAST1 (3.3%), were recovered from nondiarrheic piglets. Paa factor was detected in 8.8% and 7.5% of isolates from diarrheic and nondiarrheic piglets, respectively, and always was associated with other virulence determinants. Overall, 22.9% of isolates from diarrheic piglets appeared to be enteropathogens: enterotoxigenic E. coli (11.7%), enteropathogenic E. coli (3.5%), and E. coli isolates (3.0%) for which none of the above adherence factors was detected. Pathotypes AIDA-I/STb/EAST1 and AIDA-I/STb were isolated only from diarrheic piglets and accounted for 4.7% of isolates. Strains of these pathotypes induced diarrhea when inoculated into newborn colostrum-deprived pigs, in contrast to an isolate positive only for EAST1, which did not induce diarrhea. Antibiotic sensitivity test showed that isolates of the AIDA-I/STb/EAST1 and AIDA-I/STb pathotypes were the only strains sensitive to enrofloxacin, gentamicin, neomycin, and trimethoprim-sulfamethoxazole. This study showed that at least 20.5% of isolates from diarrheic piglets appeared to be associated with AIDA-I/STb pathotype and that EAST1 pathotype is probably not an important marker for diarrhea in piglets.