Association of genes encoding P fimbriae, CS31A antigen and EAST 1 toxin among CNF1-producing Escherichia coli strains from cattle with septicemia and diarrhea.

Fifty-six CNF1-producing Escherichia coli strains isolated from cattle with diarrhea or septicemia were screened by PCR for the detection of pap, sfa, afa, clpG, or f17 adherence factor and EAST 1 toxin genes. All the isolates were pap-positive, in accordance with the close association of pap, CNF1 and alpha-hemolysin genes observed on human and porcine E. coli. Only the gene encoding the P adhesin of class III (PrsG) was detected. Genes encoding CS31A antigen (71%) and S fimbriae (34%) (but not Afa or F17) were detected among the bovine isolates. E. coli producing both CNF1 and plasmid-encoded CS31A is a new example of association between bacterial clones and plasmid-mediated virulence factors. The EAST 1 toxin-encoding gene was detected on 66% of the CNF1-producing isolates but was linked to CS31A rather than to CNF1. These results suggest a close association between EAST 1 toxin and the adherence factor CS31A among pathogenic bovine E. coli.

Prevalence of CS31A and F165 surface antigens in Escherichia coli isolates from animals in France, Canada and India.

Bovine and porcine enterotoxigenic and non-enterotoxigenic Escherichia coli isolates from France, Canada, and India were characterized with respect to serogroup and production of fimbrial antigens CS31A and F165. Of 231 bovine isolates from the 3 countries, 20.5% produced CS31A alone, 17.7% produced F165 alone, and 17.3% produced both CS31A and F165. On the other hand, of 84 porcine isolates from Canada, 1.2% produced CS31A alone, 14.3% produced F165 alone, and no isolate produced both CS31A and F165. CS31A was found together with F5 (K99) in 7 of 16 bovine enterotoxigenic E. coli isolates of serogroups 08, 09, 020, and 023, but was not found in any of 20 F4 (K88)- or 5 F6 (987P)-positive porcine enterotoxigenic E. coli isolates. F165 was not found in enterotoxigenic E. coli. Among non-enterotoxigenic isolates, CS31A and F165 were mainly associated with serogroups 08, 09, 011, 015, 017, 023, 025, 078, 0101, 0115, 0117, 0141, and 0153.

Clonal relationships among bovine pathogenic Escherichia coli producing surface antigen CS31A.

Forty-two Escherichia coli strains producing surface antigen CS31A isolated from bovine infections were characterized with respect to OKH serotypes, outer membrane protein (OMP) electrophoretic patterns, allozymes for esterases A, B, C, I and biotypes. A large majority of the strains could be clustered in a limited number of groups of clonally related strains with diverse O serogroups. CS31A producing Escherichia coli strains thus appear to have a common genetic background and are representative of an important part of bovine pathogenic Escherichia coli.

Factors and markers of virulence in Escherichia coli from human septicemia.

One hundred Escherichia coli isolates from human septicemia were characterized with respect to O serogroups 1, 2, 4, 6, 7, 8, 15, 18, 75 and 78, alpha-hemolysin, carboxylesterase B typing, cytotoxic necrotizing factor, F165 and CS31A fimbrial antigens, aerobactin production, colicins, and antibiotic sensitivity. A factorial analysis of correspondence and chi 2 tests indicated that most of E. coli isolates belonging to the studied O serogroups were positive for the virulence factors or markers alpha-haemolysin, carboxylesterase B2 type, cytotoxic necrotizing factor, F165 fimbrial antigen and were antibiotic-sensitive (Group I). These characteristics differentiated them from E. coli isolates from other O serogroups which were generally antibiotic resistant and negative for the cited virulence factors and markers (Group II). Aerobactin and colicin production did not differentiate the two E. coli groups. E. coli O serogroups 4 and 6 were highly represented in group I and were responsible for most of the differences between the two groups.

Clonal relationships among Escherichia coli serogroup 06 isolates from human and animal infections.

The clonal relationship of thirty E. coli strains of 0 antigen serotype 06 isolated from human, dog, pig or cow infections were investigated. Two main clones with serotypes 06 : H1 or 06 : H31, H- were identified. Isolates from humans, dogs, pigs and cows were found in both clones, indicating that animals are a possible source for human extraintestinal Escherichia coli strains. Two human ETEC (06 : H16) and two pig isolates (06 : H10) were not related to the 06 : H1 or 06 : H31, H- E. coli clones.

A study of relationships among F17 a producing enterotoxigenic and non-enterotoxigenic Escherichia coli strains isolated from diarrheic calves.

We investigated the clonal relationships among 41 enterotoxigenic (ETEC) or non-enterotoxigenic (NETEC) Escherichia coli strains producing the F17 a fimbriae isolated from diarrheic calves in France or Belgium in the early 1980s. Twenty-three of the 26 ETEC strains were highly clonally related, most of them with a O101:K32:H9-serotype. The NETEC strains were also divided in clonal subgroups, most of them with O101:H-serotype. The F17 a positive ETEC strains are no longer isolated from diarrheic calves in these countries. It is postulated that the use of a vaccine including O101, K32 and H9 antigens in addition to K99 (F5) explains the strongly reduced isolation of the O101:K32:H9, K99 (F5) E. coli clone.

Characters of Escherichia coli 078 isolated from septicaemic animals.

Twenty-one Escherichia coli isolates of serogroup 078 from animal septicaemia were obtained from laboratories in France, England and Canada. The bacteria were compared for outer membrane protein (OMP) patterns, lipopolysaccharide patterns, surface proteins of fimbrial types, biotypes, antibiotypes, colicin production, hydroxamate production and virulence in mice. Sixteen isolates from bovine, ovine, porcine and avian species in France and England had a similar OMP pattern. This characteristic associated with minor properties like surface proteins type, colicin V production and virulence in mice made these 16,078 E. coli isolates from 4 animal species, good candidates for the same clonal grouping. The five other bovine isolates with "Vir" or "31a" phenotypes were heterogeneous for most of the characteristics studied.

Septicaemic Escherichia coli and experimental infection of calves.

Three strains of Escherichia coli with a common surface antigen, 31a, capable of adhering to calf enterocytes in vitro were compared to reference strains of septicaemic E. coli (RVC 330 and vir E. coli). The surface antigen 31a was present in the RVC 330 reference strain. E. coli vir had a surface antigen which was not present in E. coli 31a or E. coli RVC 330. The RVC 330 and vir reference strains also adhered to calf enterocytes in vitro. Oral infection of calves not receiving colostrum with E. coli 31a was generally followed by septicaemia and death in less than 48 h. Post-mortem examination revealed pneumonia and oedema of the kidneys and gall bladder. Oral infection of calves receiving colostrum had no effect, but intravenous inoculation produced arthritis within 15 days. The comparison of these results with those previously described by other workers did not lead to the identification of pathognomonic characteristics, which could be clearly correlated with properties specific to E. coli 31a. It is suggested that, like ColV and vir, antigen 31a may be a virulence marker for certain strains of bovine septicaemic E. coli. Furthermore, the 31a antigen appears to be carried on a plasmid.

Influence of digestive microflora on parasite development and the pathogenic effect of Eimeria ovinoidalis in the axenic, gnotoxenic and conventional lamb.

The interaction between the digestive microflora and the development and pathogenic effect of Eimeria ovinoidalis was studied in lambs. All animals were reared and fed in the same conditions and were infected on the second day after birth with 150,000 sterilised oocysts. Two conventional lambs that had absorbed colostrum had haemorrhagic diarrhoea for several days and excreted 10(5) to 10(6) oocysts g-1 faeces. One lamb died. Similar results were recorded in two gnotoxenic lambs inoculated with 63 pure bacterial strains representative of the dominant digestive microflora and free of all pathogenic organisms. By contrast, no clinical signs and, in particular, no diarrhoea were observed in nine axenic lambs. OOcyst excretion in these only started on the 16th day, and the number of oocysts was between 10(2) and 10(3) g-1. The presence of digestive microflora is thus essential to the development of the parasite's pathogenic expression.

Virulence factors and markers in Escherichia coli from calves with bacteremia.

Relative pathogenicity of 151 Escherichia coli isolates from 36 calves with bacteremia after necropsy was studied by measurement of the LD50 after mice were inoculated IP with E coli isolates. Study of virulence factors and markers revealed that the pathogenicity of E coli was associated with the production of hydroxamate siderophores and with resistance to serum bactericidal effects. Production of colicins, including colicin V, and of surface antigen 31A was correlated with virulence. The close association between phenotypic expression of virulence factors and markers was consistent with a hypothesis of a localization of genes coding for virulence factors and markers on the same plasmid.

A new diarrhoeic syndrome with ataxia in young Charolais calves: clinical and microbiological studies.

A new diarrhoeic syndrome was examined clinically in 19 one to two-week old Charolais calves. It differs from other digestive disorders in calves of this age in the discrete diarrhoeic signs, the absence of dehydration and the presence of signs of ataxia. The microbiological study carried out for three consecutive years in 58 sick calves and nine healthy control calves demonstrated the special role of E coli possessing virulence markers from septicaemic strains (CS31A, Col V). The clinical signs could be the result of bacteraemia with subacute E coli endotoxaemia.

[Kinetics of fecal excretion of Escherichia coli K99+ by calves after experimental infection]. / Cinétique d'excrétion fécale de Escherichia coli K99+ par des veaux après infection expérimentale.

Complete kinetics of fecal excretion of K99+ E. coli in colibacillary diarrhoea of young calves is not known. Six calves received two liters of colostrum as a first meal and UHT sterilized milk later. They were kept in isolators. When one week old, they received orally 2.5 X 10(10) to 9.8 X 10(10) K99+ E. coli which are able to grow on adonitol. These bacteria numbered on a minimal medium with adonitol were excreted at a level between 10(5) to 10(8)/g of feces during about eight days. Calves a few weeks old might be healthy carriers of K99+ E. coli and contaminate newborn calves which are highly sensitive to enterotoxigenic colibacillary diarrhoea.

Additive protective effects of colostral antipili antibodies in calves experimentally infected with enterotoxigenic Escherichia coli.

With oral infection of calves by an enterotoxigenic Escherichia coli strain carrying K99, F41, and FY adhesins, colostrums from cows vaccinated against either K99+F41 or FY did not provide protection, but a mixture of the two colostrums did. The association of antibodies directed against the different adhesins is more effective than antibodies directed against one adhesin alone for colostral protection against enterotoxigenic E. coli carrying several adhesins.

Non-radioactive oligonucleotide probe for detection of clinical enterotoxigenic Escherichia coli isolates of bovine origin.

Oligonucleotides (32 or 34 mer) corresponding to enterotoxigenic Escherichia coli STIa (ST-P) toxin gene were tailed with Bio-11-dUTP using terminal deoxynucleotidyl transferase. Plasmids from clinical E. coli isolates were prepared by modified rapid alkaline lysis procedure and dot-spotted. Biotinylated oligonucleotide probes were hybridized to detect the STIa toxin gene. The results were in agreement with that obtained by radioactive oligonucleotide probes. Of 135 clinical isolates (sampled from 6 different regions of France), only 7 (5.2%) were found to be STIa+. These 7 isolates were the only ones to be found positive for the K99 adhesive pili antigen. Both the probes were specific to the STIa toxin gene and failed to detect the closely related STIb (ST-H) toxin gene. Possibilities of their wide usage in clinical labs are discussed.

Interferon activity in rotavirus infected newborn calves.

A viral inhibitor displaying the main properties of a type 1 (alpha or beta) interferon was found in intestine and serum of diarrheic newborn calves following oral administration of bovine rotavirus. Other internal organs examined 24 hours after infection all contained appreciable amounts of interferon. A kinetic study performed in ileum and serum of a one day-old calf showed a good time correspondence between peak levels of virus multiplication in the gut, intestinal interferon, and systemic interferon. In the same experiment, a two week-old calf was refractory to the disease, developing much delayed and weaker productions of both virus and interferon, when compared to the newborn calf. Therefore, the enhanced susceptibility of the newborn calf to rotavirus induced diarrhea is not related to a deficiency in interferon synthesis.

CS31A, a new K88-related fimbrial antigen on bovine enterotoxigenic and septicemic Escherichia coli strains.

The nature of the common surface antigen of six hemagglutinating and adhesive piliated Escherichia coli strains isolated from diarrheic or septicemic calves was studied. By electron microscopy studies, the E. coli surface antigen designated CS31A was found on bacterial cells and in purified form to consist of thin (2-nm) "fibrillar" fimbriae. E. coli 31A, which was cured of a 105-megadalton plasmid, failed to express CS31A fimbriae, but retained the ability to hemagglutinate and to adhere in vitro on intestinal cells. Conversely, E. coli K-12, harboring the 105-megadalton plasmid originating from strain 31A, produced CS31A fimbriae but was not able to hemagglutinate or adhere on intestinal cells. A single fimbrial subunit of 29 kilodaltons was observed when purified fimbriae from the 105-megadalton plasmid-containing E. coli K-12 strain was subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis or eluted by gel filtration after dissociation by 8.5 M guanidium hydrochloride from an S300 Sephacryl column. Western immunoblot analysis and the N-terminal sequence and amino acid composition of CS31A indicate structural and immunological relatedness between CS31A and K88 protein subunits.

[Anti-K99 vaccination and colostric protection of calves infected experimentally with Escherichia coli K99]. / Vaccination anti-K99 et protection colostrale des veaux infectés expérimentalement avec Escherichia coli K99.

Colostral antibodies of cows vaccinated with E. coli B41 (O101: K99, F41) protect completely B41 experimentally infected calves. In order to know more precisely the role of K99, F41 antibodies in protection, calves receiving the colostrum of B41 vaccinated cows are infected with E. coli B44 (O9: K30: H-K99, F41). Vaccination multiplies K99 antibodies in colostrum by seven. In B44 infected calves, specific K99, F41 antibodies protect only 3 out of 6 calves completely. Additive effect of antibodies against K99 and other surface antigens of enterotoxigenic E. coli seems desirable for a more complete protection.

Specific protection by colostrum from cows vaccinated with the K 99 antigen in newborn calves experimentally infected with E. coli Ent+ K99+.

We have measured the protective effect of colostrum of vaccinated cows with the K99 antigen comparatively with the colostrum of non vaccinated cows, in calves receiving at birth 2 liters of colostrum and just after 5 times 10(10) to 1 times 10(11) E. coli Ent+, K99+. The K99 antigen was prepared from E coli B41 (0101:K99:H-) cultured in a fermentor. Cows were vaccinated subcutaneously with 100 mg or 300 mg (wet weight) in emulsion in Freund uncomplete adjuvant 45 and 15 days before parturition. Of 4 calves receiving a colostrum of non vaccinated cows 4 had a diarrhoea, 3 became dehydrated and 2 died. Of 6 calves receiving colostrum of vaccinated cows, 5 were healthy and the 6th calf had a mild diarrhoea for few hours and became again healthy. Control and protected calves excreted E. coli K99+, 24 HOURS AFTER INFECTION. The protection is probably due to K99 antibodies which inhibit adhesion of E. coli K99+ to the intestinal epithelium.

[Diarrhea of the newborn animal: nature and mechanism of action of enteropathogenic Escherichia coli in the calf and piglet]. / Diarrhée du nouveau-né: propriétés et mécanismes d'action des Escherichia coli entéropathogènes chez le veau et le porcelet.

The present knowledge of the enteropathogenic characteristics of Escherichia coli (adhesion and toxinogenesis) is reviewed in the calf, and compared with piglet data. A pathogenic model of E. coli diarrhoea in the calf is proposed, taking into account the electromyographic, bacteriologic and physiologic data.