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M Contrepois

Publications and source records attributed to M Contrepois.

At least 37 records · Page 2Linked to original sources
PubMed1988

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.

Animals↗
PubMed1988

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.

Amino Acid Sequence↗
PubMed1986

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.

Animals↗
PubMed1985

[Frequency of FY and K99 pili in strains of Escherichia coli isolated from diarrheal calves in France].

Epidemiological study of bovine E. coli shows that the FY E. coli pilus which has previously been described and is also known as Att25, can be found in 30 of 415 fecal samples of diarrheic calves, eight of them carrying both FY and K99 pili. The K99 E. coli pilus is present in 86 fecal samples. Strains carrying both FY and K99 pili account for 9% of K99 enterotoxigenic E. coli. K99-, FY+ E. coli do not produce the thermostable enterotoxin (TSa). K99+, FY- or K99+, FY+ E. coli are present mainly in calves under three days old but K99- FY+ E. coli are found whatever the age of the animal.

Age Factors↗
PubMed1985

[Anti-K99 vaccination and colostric protection of calves infected experimentally with 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.

Animals↗
PubMed1984

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.

Animals↗
PubMed1983

Expression of K99 pilus of E. coli.

Different factors are involved in production and (or) detection of K99. They are modifications in plasmid contents of the strains, the size of capsular antigens, the quantity of K99 protein produced according to the culture media. We made a distinction between the strains which produced K99 on Minca medium without glucose (K99-C) and those which needed glucose for production on this medium (K99-GD). The K99-GD strains were able to use adonitol and most K99-C strains did not. With strains K99-C we showed that heavily capsulated colonies produced as much K99 than non capsulated colonies, but heavily capsulated ones were hardly detected with slide agglutination. According to the carbon substrate, differences were observed in K99 production. Mannose was a bad carbon source for K99 production, the synthesis of which was completely inhibited with K99-GD strains, but not with K99-C strains. Adonitol was a good substrate for detection of K99 from K99-GD strains. Measure of intracellular AMPc showed that there was non catabolite repression for K99 biosynthesis. In the opposite, high intracellular level of AMPc was correlated with a low production of K99. Plasmid contents of the strains indicated that most strains had one or two plasmids in the range of 50-70 megadaltons. Small differences in plasmids are sometimes correlated with modifications in the quantity of K99 produced. The main conclusions were that the distinctions that we proposed between K99-C and K99-GD could help understand the mechanisms of K99 production.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

[Kinetics of fecal excretion of Escherichia coli K99+ by calves after experimental infection].

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.

Animals↗
PubMed1981

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.

Animals↗
PubMed1981

[Incidence of rotavirus infection and in combined infection of rotavirus and enteropathogenic Escherichia coli in French calves (author's transl)].

Detection of a rotavirus in faeces of 789 calves developing diarrhoea gave positive results among 48% of the calves. The same investigation extended to 96 apparently healthy animals shows that 12.5% of the faeces contained rotavirus. It appears that all the last ones cannot be considered as healthy controls. Association of rotavirus and E. coli K99+ is found in 5% of sick animals less than 10 days old.

Age Factors↗
PubMed1981

[Frequence of K99 antigen and antibioresistance in Escherichia coli from calves in France (author's transl)].

During the winter of 1979-1980, an epizootiological study of diarrhoeic calves revealed the presence of K99+ E. coli among 8.2 p. cent of clinically healthy calves and in 18.9 p. cent of diseases calves. Some calves which seemed healthy on the day of sampling possibly became diarrhoeic on the following days. In diarrhoeic calves, K99+ E. coli were mainly found during the early life, i.e. in 33.7 p. cent of calves less than 4 days old. These results were obtained with 147 healthy calves and 1053 diarrhoeic calves. They confirmed previous results obtained with more limited numbers of animals. Moreover, K99+ E. coli were found in all breeding systems. Antibiotics resistance among the isolated E. coli were very high, especially in K99+ strains. The results proved the interest of E. coli K99 diagnosis in liquid diarrhoea of very young calves.

Age Factors↗
PubMed1978

The experimental production of diarrhoea in colostrum deprived axenic and gnotoxenic calves with enteropathogenic Escherichia coli, rotavirus, coronavirus and in a combined infection of rotavirus and E. coli.

We attempted to produce diarrhoea experimentally in the newborn calf by orally injecting 17 colostrum-deprived calves with two serotypes of Escherichia coli Ent+ K99+, a rotavirus and a coronavirus. With E. coli alone, a dose of 2 x 10(8) bacteria administered 24 hours after birth causes a mild attack of diarrhoea, whereas 1 x 10(10) bacteria leads to dehydration and death. An inoculation of rotavirus is followed by diarrhoea which always contains large quantities of rotavirus. These animals were anorectic for a time, but none was dehydrated or died. With coronavirus, there were large quantities of watery diarrhoea, which led to dehydration and death. The inoculation of rotavirus, not lethal in itself, followed by a similarly non lethal inoculation of E. coli in doses of 3 x 10(8) to 2 x 10(9) led to dehydration and death. The authors conclude that dehydration and death of the animal can caused by large doses of E. coli or coronavirus or by two non-lethal doses of rotavirus and E. coli administered one after the other.

Animals↗
PubMed1978

Scanning electron microscopy of abomasium and intestine of gnotoxenic calves infected either with rotavirus, coronarivus or enteropathogenic Escherichia coli or with rotavirus and E. coli.

Neonatal calf diarrhoea induced with several agents of infection was studied by scanning electron microscopy. In a gnotoxenic calf infected with E. coli K99+ Ent+, slight lesions of the small intestine were observed and desquamation or puffiness of microvilli occurred. In rotavirus-infected calves, the abomasum was covered with abudant mucous film and appeared to be desquamated. In the small intestine, no desquamation of epithelium was observed. Inoculation of the rotavirus and E. coli induced severe diarrhoea. The whole digestive tract, even the abomasum and colon, was eroded. Coronavirus induced marked lesions in all levels of the intestine. These results demonstrate unequivocally the pathogenic properties of the three infectious agnets, the synergistic effect of E. coli and rotavirus. Furthermore, the importance of the abomasum in neonatal diarrhoea is emphasized.

Abomasum↗
PubMed1978

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.

Animals↗