Serotypes, virulence genes and intimin types of verotoxin-producing Escherichia coli and enteropathogenic E. coli isolated from healthy dairy goats in Spain

Faecal samples from 222 healthy dairy goats on 12 farms in Spain, as well as bulk tank milk samples of these farms, were screened for the presence of verotoxin-producing Escherichia coli (VTEC) and enteropathogenic E. coli (EPEC). VTEC and EPEC were isolated in 47.7 and 7.7% of the animals, respectively. VTEC were isolated more frequently from adults and replacement animals than from goat kids. In contrast, EPEC were detected more frequently from goat kids than from replacement animals and adults. VTEC or EPEC strains were not detected in the bulk tank milk samples. Although a selective enrichment protocol was used, the serotype O157:H7 was not detected. The most frequent serotypes among the 106 VTEC strains isolated from goats were O5:H-, O76:H19, O126:H8, O146:H21, ONT:H- and ONT:H21. None VTEC strain was eae-positive. The absence of the eae gene in the VTEC strains could indicate that these strains are less virulent for humans that the classical eae-positive enterohaemorrhagic E. coli types. However, 16% of VTEC strains isolated from healthy goats belonged to serotypes associated with haemolytic uraemic syndrome in humans. The ehxA gene was detected in 84.9 and 52.9% of the VTEC and EPEC from goats, respectively. The beta1, theta/gamma2 and zeta were the most frequent intimin types among the 17 EPEC strains studied and the most prevalent serotypes of these strains were O156:H25 and O177:H11. Our data show that in Spain healthy goats are an important reservoir of VTEC and EPEC, and a potential source of infection for humans.     

Serotypes,phage types and virulence genes of shiga-producing Escherichia coli isolated from sheep in Spain

PROBLEM ADDRESSED: Shiga toxin-producing Escherichia coli (STEC), have emerged as food poisoning pathogens which can cause severe diseases in humans. OBJECTIVE: The aim of this study was to determinate the serotypes and virulence genes of STEC strains isolated from sheep in Spain, with the purpose of determining whether sheep represent a potential source of STEC pathogenic for humans. METHODS AND APPROACH: Faecal swabs obtained from 697 healthy lambs on 35 flocks in Spain during the years 2000 and 2001 were examined for STEC using phenotypic (Vero cells) and genotypic (PCR) methods. RESULTS: STEC O157:H7 strains were isolated from seven (1%) animals in six flocks, whereas non-O157 STEC strains were isolated from 246 (35%) lambs in 33 flocks. A total of 253 ovine STEC strains were identified in this study. PCR showed that 110 (43%) strains carried stx(1) genes, 10 (4%) possessed stx(2) genes and 133 (53%) both stx(1) and stx(2). Enterohaemolysin (ehxA) and intimin (eae) virulence genes were detected in 120 (47%) and in 9 (4%) of the STEC strains. STEC strains belonged to 22 O serogroups and 44 O:H serotypes. However, 70% were of one of these six serogroups (O6, O91, O117, O128, O146, O166) and 71% belonged to only nine serotypes (O6:H10, O76:H19, O91:H-, O117:H-, O128:H-, O128:H2, O146:H21, O157:H7, O166:H28). A total of 10 new O:H serotypes not previously reported in STEC strains were found in this study. Seven strains of serotype O157:H7 possessed intimin type gamma1, and two strains of serotype O156:H- had the new intimin zeta. STEC O157:H7 strains were phage types 54 (four strains), 34 (two strains) and 14 (one strain). CONCLUSIONS: This study confirms that healthy sheep are a major reservoir of STEC pathogenic for humans. However, because the eae gene is present only in a very small proportion of ovine non-O157 STEC, most ovine strains may be less pathogenic.     

Serotypes and intimin types of intestinal and faecal strains of eae+ Escherichia coli from weaned pigs

Enteropathogenic Escherichia coli (EPEC) that are known to cause severe diarrhoea in children and young rabbits are well characterized, but there are few reports on the serotypes and intimin (eae) types of EPEC in weaned pigs. Based on detection of the eae gene by PCR and by DNA-hybridisation with LEE specific gene probes, 20 intestinal and 17 faecal eae(+) strains from diarrhoeal (164) and non-diarrhoeal (57) weaned pigs from 13 Hungarian farms, representing 12.8% of diarrhoeal and 14.0% of non-diarrhoeal pigs, were identified. The dominant serotype was O123:H11 (40%) among intestinal, and O108:H9 (23%) among faecal strains. The majority (85%) of the intestinal strains possessed eae-beta and 10% carried eae-gamma gene. In contrast, significantly (p<0.025) fewer faecal strains (53%) harboured the eae-beta gene, and 23% were eae-gamma positive. In vitro adhesion tests of intestinal and faecal eae(+) strains indicated adhesion of 20/37 of the strains to PK15 (porcine kidney) cells while only 3/37 strains adhered to HeLa cells. The ultrastructure of intimate bacterial attachment of representative porcine eae(+) strains to PK15 cells showed no pedestal formation, in contrast to the human EPEC (O127:H5, eae-alpha) strain. In conclusion, the data do not demonstrate a significant role for the eae(+)E. coli in porcine post-weaning diarrhoea, but provide new information on a dominant porcine serotype (O123:H11, eae-beta), and on differences of serotypes and intimin types of porcine eae(+) strains according to their site of isolation. Furthermore there was an indication that the PK15 cell line could be used as a model to study in vitro adherence of eae(+)E. coli of some human and porcine origin.     

Serotypes and virulence factors of Escherichia coli strains isolated from dogs and cats

E. coli strains isolated from urine of dogs and cats with urinary tract infections (UTI) and from feces of healthy one's were serotyped, and the serotypes were correlated with uropathogenic virulence factors. The most prevalent O-serotypes, O4 and O6, were isolated from dogs and cats with UTI. In contrast, O11 and O102 strains were the most frequently found from feces of healthy dogs and cats. Most of type O4 and O6 strains possessed such virulence factors as pil, pap, sfa, hly, and cnf1, while most type O11 and O102 strains pil only or pil and aer. All strains of type O75 possessed afaI and aer. K1 antigen was negative in all strains obtained from UTI.     

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.     

Serotypes and virulence genes of bovine Shigatoxigenic Escherichia coli (STEC) isolated from a feedlot in Argentina

Grazing-fed cattle were previously demonstrated to be reservoir of non-O157 Shigatoxigenic Escherichia coli (STEC) serotypes in Argentina. The acid-resistance of some STEC strains makes it reasonable to assume the presence in feedlot of particular STEC serotypes. Fifty-nine animals were sampled every 2 weeks during 6 months by rectal swabs. Twenty-seven of 59 animals (45.8%) were shown to be Stx2(+); 3/59 (5.1%) carried Stx1(+) and 7/59 (11.9%) were Stx1(+) Stx2(+). Among 44 STEC isolates, 31 isolates were associated to 10 O serogroups (O2, O15, O25, O103, O145, O146, O157, O171, O174, O175) and 13 were considered non-typable (NT). Six H antigens (H2, H7, H8, H19, H21, H25) were distributed in 21 isolates whereas 23 were non-mobile (H-). Seventeen of 44 strains (38.6%) were eaeA(+) and 14 (31.8%) harbored the 60MDa plasmid. The megaplasmid (Mp) and eaeA gene were simultaneously found in a limited number of serotypes belonging to the enterohaemorrhagic E. coli (EHEC). E. coli O157:H7 strains, isolated from four (6.8%) animals, corresponded to the Stx2(+), eaeA(+), Mp(+) pattern. Three O157:H7 strains belonged to phage type 4 and the other strain was atypical. Many serotypes isolated from grain-fed cattle (O2:H25, O15:H21, O25:H19, O145:H-, O146:H-, O146:H21, O157:H7, O175:H8) also differed from those isolated by us previously from grazing animals. The serotypes O15:H21, O25:H19 and O175:H8 had not been identified at present as belonging to STEC. This work provides new data for the understanding of the ecology of STEC in grain-fed cattle and confirms that cattle are an important reservoir of STEC.     

Frequency of virulence factors in Escherichia coli isolated from suckling pigs with diarrhoea in China

Escherichia coli-associated diarrhoea is an important disease adversely affecting the pig industry. This study was conducted to investigate the frequency of virulence factors expressed by E. coli strains isolated from suckling pigs with diarrhoea in China. A total of 381 E. coli strains, obtained from 290 faecal samples from pigs on 38 farms, were tested for fimbriae (K88, K99, 987P, F41, F18, F17), non-fimbrial adhesins (AIDA-I, paa, CS31A, eae, saa), enterotoxin (LT-I, LT-II, STa, STb, EAST1), Shiga toxin (Stx1, Stx2, Stx2e), pathogenicity islands (HPI, LEE), α-haemolysin (hlyA), afa8 gene cluster (afaD, afaE) and sepA genes by PCR. Out of the 381 isolates, 206 carried at least one virulence gene. Of the 206 virulence positive isolates, the virulence factor genes detected were EAST1 (n = 120), irp2 (n = 59), paa (n = 50), STb (n = 41), AIDA-I (n = 34), LT-I (n = 23), ler (n = 11), hlyA (n = 9), K88 (n = 8), eae (n = 8), STa (n = 7), sepA (n = 6), F18 (n = 5), afaD (n = 3), afaE (n = 3), K99 (n = 2) and Stx2e (n = 1), with most isolates carrying multiple virulence genes. These results demonstrate that relatively few isolates from the study population express K88, K99, LT-I or STa, but that EAST1 (58%), irp2 (29%), AIDA-I (16.5%), paa (24%) and STb (20%) are frequent virulence factors expressed by E. coli strains isolated from suckling pigs with diarrhoea in China.     

Serotypes and virulence genes of extraintestinal pathogenic Escherichia coli isolates from diseased pigs in China

Extraintestinal pathogenic Escherichia coli (ExPEC) isolates were detected in 315/3127 (10.1%) diseased pigs from 19 provinces of China; the frequency of isolation increased from 3.1% in 2004 to 14.6% in 2007. All isolates were characterised for O serogroups, haemolysis, phenotypic and genotypic antimicrobial resistance, virulence genes and pathogenicity. The most prevalent serogroups were O161, O8, O11, O138, O101 and O26; 83/315 (26.3%) isolates were haemolytic. Forty percent of isolates in phylogenetic groups B2 and D were highly virulent porcine ExPEC strains. Thirty-three putative extraintestinal virulence factor genes that are normally associated with human and/or avian ExPEC strains were widely present in porcine isolates. These results indicate that ExPEC are prevalent in pigs in China and represent a potential public health threat.     

Isolation of Escherichia coli from piglets in South Korea with diarrhea and characteristics of the virulence genes

Escherichia coli was isolated from the feces of 122 piglets with diarrhea on 55 farms in Korea. The virulence genes of each isolate were characterized by polymerase chain reaction (PCR). Of the 562 isolates, 191 carried 1 or more of the virulence genes tested for in this study. Of the 191 isolates, 114 (60%) carried 1 or more of the genes for enterotoxigenic E. coli (ETEC) fimbriae F4, F5, F6, F18, and F41 and ETEC toxins LT, STa, and STb, 57 (30%) carried 1 or more of the genes for the Shiga-toxin-producing E. coli (STEC) toxins Stx1, Stx2, and Stx2e, and 21% and 37% carried the gene for enteropathogenic E. coli intimin and for enteroaggregative E. coli toxin, respectively. Collectively, our results indicate that other pathotypes of E. coli as well as ETEC can be strongly associated with diarrhea in piglets. In addition, detection of the genes for Stx1 and Stx2 indicates that pigs are reservoirs of human pathogenic STEC.     

Virulence gene profiles and intimin subtypes of Shiga toxin-producing Escherichia coli isolated from healthy and diarrhoeic calves

The virulence properties of Shiga toxin-producing Escherichia coli (STEC) strains isolated from diarrhoeic and non-diarrhoeic calves were compared. The strains were also tested for O157:H7, O111 and O26 serotypes, using PCR and conventional serotyping methods. E coli strains isolated from 297 faecal samples, from 200 diarrhoeic and 97 non-diarrhoeic calves, were screened by multiplex PCR assay for the stx1, stx2, eae and Ehly virulence genes. STECs were recovered from 8 per cent of diarrhoeic calves and 10.3 per cent of non-diarrhoeic calves. The predominant virulence gene profile was stx1/eae/Ehly (47.3 per cent) among isolates from diarrhoeic calves and eae/Ehly (36.8 per cent) among isolates from non-diarrhoeic calves. Among three tested serogroups, the predominant serogroup was O26 (18.4 per cent), and O157:H7 was not detected. Intimin subtyping by restriction fragment length polymorphism analysis revealed only three intimin subtypes (β, γ and ). A significant difference was observed in the distribution of Int- between two groups. Int- was present in 50 per cent of the isolates from diarrhoeic calves and in 11.1 per cent of the isolates from non-diarrhoeic calves; this difference was statistically significant (P=0.01).     

宠物源大肠杆菌的血清型和毒力基因及耐药性调查

为研究宠物源致病性大肠杆菌(Escherichia coli)的血清型、毒力基因和耐药性之间的相关性,本研究由健康和患病犬、猫直肠拭子样品中分离177株E.coli,并采用玻片凝集法鉴定其血清型,结果显示分离株中定型菌株135株,分别属于20个不同的血清型,其中O1、O2和O8为主要的流行血清型。PCR方法检测11种毒力相关基因,并采用琼脂稀释法测定分离菌株对14种抗菌药的敏感性,结果表明3个血清型的菌株拥有相似的耐药表型,但毒力基因谱不同。62%的分离菌株携带fimH基因,并且毒力基因组合iroN+hlyF、iroN+fimH和traT+sitA比较流行。55%的O1血清型携带fimH基因,并且多数耐受四环素、多西环素、头孢噻吩和庆大霉素;20.8%的O2血清型菌株携带traT和sitA基因;50%的O8血清型携带traT和fimH基因。3个血清型分离菌株多数对安普霉素和阿米卡星敏感。     

Prevalence of serogroups and virulence factors of Escherichia coli strains isolated from pigs with postweaning diarrhoea in eastern China

This study was undertaken to determine the present distribution of serogroups, hemolytic activity and virulence factors among Escherichia coli strains isolated from pigs with postweaning diarrhoea from eight provinces in eastern China. Two hundred and fifteen E. coli isolates were serogrouped with O-antisera, investigated for hemolytic activity, assessed for F4, F5, F6, F18 and F41 fimbrial antigens by monoclonal antibodies and detected for genes of enterotoxins and shiga-toxin-two-variant (Stx2e) by a multiplex polymerase chain reaction (PCR). Among these E. coli isolates, 140 were determined to be placed in serogroups, 52 were unable to be serogrouped and the rest 23 auto-agglutinated. These isolates distributed in 45 serogroups and 64.3% (90/140) belonged to 12 O serogroups: O8, O9, O11, O20, O32, O91, O93, O101, O107, O115, O116 and O131. Hemolytic activity was detected in 11.6% (25/215) of all isolates. Several uncommon O serogroups were discovered in this study. Agglutination tests showed that 50.2% (108/215) of these isolates were positive for one or more of the five fimbrial antigens. Seventy-two E. coli strains expressed single fimbria and 36 strains expressed two or more fimbriae. Among these 215 E. coli isolates, strains expressing F18, F4, F6, F6 + F18 or F5 + F41 occurred more frequently. PCR analysis showed that 60.5% (130/215) of the isolates only harboured the gene of estI (STI) while 6.0% (13/215) strains possessed the genes of stx2e, estI and estII and 5.6% (12/215) of strains had the genes of estI/estII. Of all these isolates, 107 (49.8%) were negative for the fimbrial antigens examined. The fimbria-negative isolates usually possessed genetic determinant of estI (78, 72.9%).     

Rapid identification of virulence genes in enterotoxigenic Escherichia coli isolates associated with diarrhoea in Queensland piggeries

OBJECTIVE: To identify virulence genes in enterotoxigenic E coli (ETEC) isolates associated with diarrhoea in neonatal, 1 to 3 week-old and weaned pigs in southeast Queensland. DESIGN: Multiplex PCR and serotyping were applied to E coli isolates obtained over a 5-year period (1998-2002) from cases diagnosed at Toowoomba Veterinary Laboratory. PROCEDURE: A total of 126 isolates from 25 different Queensland piggeries were tested for haemolytic activity on 5% sheep blood agar and by multiplex PCR for the presence of five commonly recognised fimbrial (F4, F5, F6, F41 and F18) and three enterotoxin genes (STa, STb, LT). A subset of 62 representative isolates were serotyped by slide agglutination. For comparative purposes, multiplex PCR was also performed on the DNA of 31 ETEC isolates from 9 serotypes originating from piggeries in southern New South Wales. RESULTS: A total of 113 (89.7%) of the isolates from Queensland possessed ETEC virulence genes, including 14 of 15 isolates from neonatal pigs (93.3%), 18 of 23 isolates from 1 to 3 week old pigs (78.3%) and 81 of 88 isolates from weaned pigs (92.1%). F4:STa:STb:LT (serotype O149) was the most prevalent pathotype in neonatal and 1-3 week old pigs and F4:STa:STb:LT (serotype O149) and F18:STa:STb:LT (serotype O141) were most prevalent in weaned pigs. In comparison, isolates obtained from neonatal pigs from New South Wales belonged to a more diverse range of pathotypes and serotypes. CONCLUSION: Multiplex PCR was a rapid and specific method for detecting the presence of ETEC virulence genes in porcine E coli isolates. For isolates obtained from cases of suspected colibacillosis in Queensland, growth of a heavy pure culture of haemolytic E coli was a sensitive prognostic indicator of the presence of ETEC virulence genes in the isolate. ETEC pathotypes and serotypes remained stable in Queensland piggeries over the five-year study period and appear to have changed little over the last three decades.     

CTX-M-9亚群鸡大肠杆菌的遗传背景及毒力基因特性

探讨鸡大肠杆菌bla_(CTX-M-9)的遗传背景和毒力因子流行特征,为进一步研究bla_(CTX-M-9)与致病特性是否相关奠定基础。取近年来收集的17株产CTX-M-9族鸡大肠杆菌为研究对象,分别采用定位PCR、多重PCR等技术检测受试菌株的种系发育、MLST序列、质粒复制子特性、bla_(CTX-M-9)的上、下游基因环境及其携带的31种毒力基因。结果显示,bla_(CTX-M-9)的上游均含有ISEcpl,部分被IS26截断,下游最常见的是IS903。受试菌ST分型多样化,17株菌分别属于12种不同的ST型。受试菌携带3种以上复制子,最常见的是IncFII复制子,其次为IncFIB、IncK和IncI1型。受试菌分属于种系发育的D群(7株)、B1群(6株)和A群(4株),未检出强致病力的B2群菌株。受试菌均含有fimH、traT和feoB毒力基因,同时毒力基因检测率较高的还有sit A、iut A、iucC、iroN和iss基因。结果表明,ISEcpl和IS903转座子、IncF在bla_(CTX-M-9)快速散播过程中发挥了重要的作用,克隆传播仅发挥了次要的作用;产CTX-M-9族鸡大肠杆菌含有较多的毒力基因,具有一定的致病力。     

Preliminary characterization of Escherichia coli isolated from pigs with diarrhoea in Venezuela

The aetiology of neonatal porcine diarrhoea was studied in 15 different herds located in the north-western region of Venezuela. Of 56 strains of Escherichia coli analyzed, 16 (28.6%) were shown to produce heat-stable (STa) enterotoxin, as detected by infant mouse assay. Only four of these STa+ isolates also possessed the K88 pilus antigen, two were 987P+ and none possessed the K99 antigen, leaving 10 STa+ samples in which no pilus antigen was identified. Among the 40 STa negative samples were six K88+ specimens, one K99+, four 987P+, one which reacted as K88+ + K99+ and one K88+ + 987P+. Considering as pathogenic any strain showing at least one of the characters studied, pathogenic E. coli were detected with an overall frequency of 42.9%, being more prevalent during the second week of life. An electrophoretic analysis of the plasmid content of the field isolates of E. coli, revealed the presence of numerous species of extrachromosomal DNA, although no direction association could be made between a particular plasmid and any of the pathogenic characteristics identified. Results of Southern blot analysis indicate that the STa enterotoxin was preferentially encoded within an endemic plasmid of 4.9 Md. Other plasmids present in the E. coli isolates could be related to antibiotic resistance. With the exception of one strain, all E. coli isolates were resistant to more than one of the nine drugs tested; multiresistant E. coli were frequently isolated, including four strains which were resistant to seven antibiotics.     

一规模化猪场断奶仔猪腹泻大肠杆菌毒力因子的检测

从疑似断奶仔猪腹泻的仔猪中分离、鉴定出15株病原性大肠杆菌。经O血清型鉴定,11株为0131、4株未定型,所有O131血清型菌株呈β溶血。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,O131菌株的毒素为STa、STb、SLT-2e,表达F18粘附素,未定型菌株的毒素为STa,共表达F6和F18粘附素。对15株大肠杆菌用16种抗生素进行药敏试验,结果表明:分离株对阿米卡星、痢特灵、新霉素敏感,而对多种抗生素产生了不同程度的耐药性。运用本场大肠杆菌分离株灭活苗免疫猪群,取得良好效果。     

Colonization antigens,antibiotic resistance and plasmid content of enterotoxigenic Escherichia coli isolated from piglets with diarrhoea in galicia (North-Western Spain)

Escherichia coli colonies isolated from 50 diarrhoeic and 29 healthy piglets were investigated for several properties related to pathogenicity, such as production of heat-labile (LT) and heat-stable (STa) enterotoxins, presence of K88 and K99 colonization antigens, mannose-resistant haemagglutinating activity (MRHA), β-haemolysis and antibiotic resistance. The objective was to establish the toxic and adhesive abilities of E. coli strains that cause porcine diarrhoea in Galician farms. Fifty-seven colonies from 14 diarrhoeic piglets formed STa, while no STa⁺ colony was detected from healty piglets. Thirty-four of the 57 STa⁺ colonies were resistant to gentamicin. Sixteen representative STa⁺ strains isolated from the 14 infected piglets were serotyped, investigated for plasmid content and examined by electron microscopy. Of these STa⁺ strains, 15 belonged to serotype 0141:K85ab and carried on their surface the fimbrial antigen P987. The remaining representative STa⁺ strain belonged to serotype 0101:K30 and was K99⁺, being the only STa⁺ strain with MRHA activity. All 15 STa⁺ P987⁺ strains possessed a similar plasmid pattern, with three plasmids ranging in molecular weight from 33 × 10⁶ to 74 × 10⁶; nine of the gentamicin-resistant strains possessed an additional plasmid of molecular weight 16 × 10⁶, which was absent in the six gentamicin-sensitive strains. Strains producing LT or K88 antigen were not detected. Forty-one MRHA⁺ colonies were isolated at similar rates from both diarrhoeic and healthy piglets. Twelve of the 19 non-enterotoxigenic MRHA⁺ strains of which the O-group was established, belonged to serogroups (01, 02, 07, 08, 09 and 075) typical of the human E. coli strains that cause extraintestinal infections. Finally, a statistically significant association between haemolytic and MRHA activities in porcine E. coli was found. In conclusion, it was found that STa⁺E. coli strains belonging to serotype 0141:K85ab:P987 are associated with porcine diarrhoea in Galicia. Additionally, no correlation between the isolation of non-ETEC MRHA⁺ strains and diarrhoea was observed.     

Prevalence of virulence factors of Escherichia coli strains isolated from diarrheic and healthy piglets after weaning.

This study determined the prevalence of F4, F5, F6, F17 and F41 fimbriae and the genes for FedA (F18 fimbriae), LT and ST enterotoxins, and Shiga toxins Stx1, Stx2 and Stx2e among E. coli isolated from 372 weaned pigs with diarrhea and 46 healthy pigs of the same age. Agglutination tests showed that most isolates were negative for all five fimbrial antigens. The F4 antigen was found in 71 (19.1%) and the F5, F6, or F41 antigen was detected in 6.4% of isolates from diseased pigs. Genes for the F18 fimbriae were detected in 10 (2.7%) strains from diarrheic pigs and in 1 of 46 isolates from healthy pigs. Most isolates (213, 57.3%) from pigs with diarrhea were positive for LTI only or for LTI and STI or Stx2e toxin genes. Fifteen strains (13.7%) possessed only the STI or STII toxin genes. All F4-positive bacteria had genes for LTI or LTI and STI, whereas F18-positive isolates had genes for LTI, LTI/STI, or LTI/Stx2e. Of the strains isolated from diseased pigs, 264 (71.0%) were negative for the fimbrial antigens (genes) examined in this study. The fimbria-negative isolates frequently possessed genetic determinants for LTI (118, 31.7%) or for STII (16, 4.3%) enterotoxins.