The ability of rabbit hemorrhagic disease virus to agglutinate human erythrocytes and to attach to rabbit epithelial cells of the upper respiratory and digestive tracts was shown to depend on the presence of ABH blood group antigens. Indeed, agglutination was inhibited by saliva from secretor individuals but not from nonsecretors, the latter being devoid of H antigen. In addition, erythrocytes of the rare Bombay phenotype, which completely lack ABH antigens, were not agglutinated. Native viral particles from extracts of infected rabbit liver as well as virus-like particles from the recombinant virus capsid protein specifically bound to synthetic A and H type 2 blood group oligosaccharides. Both types of particles could attach to adult rabbit epithelial cells of the upper respiratory and digestive tracts. This binding paralleled that of anti-H type 2 blood group reagents and was inhibited by the H type 2-specific lectin UEA-I and polyacrylamide-conjugated H type 2 trisaccharide. Young rabbit tissues were almost devoid of A and H type 2 antigens, and only very weak binding of virus particles could be obtained on these tissues. Rabbit hemorragic disease virus (RHDV) is a noncultivablecalicivirus that infects rabbits and causes epidemics of an acute fatal hepatitis. The disease is characterized by high morbidity and mortality rates for adult animals. Death is the result of a widespread circulation dysfunction associated with disseminated intravascular coagulation and necrotizing hepatitis lesions (14, 24). Large quantities of virus particles are found in several organs, especially the liver, which is considered the major site of virus replication (6,14,19,27). The viral genome consists of a single-stranded RNA of nearly 7.5 kb, packaged in a small icosahedral capsid (3, 15). The capsid protein has an estimated molecular mass of 60 kDa (VP60) (16), and expression of the corresponding cDNA in insect cells infected with a recombinant baculovirus yields a protein that spontaneously assembles into virus-like particles (VLPs). These VLPs are both antigenically and morphologically similar to native RHDV particles (11,23). Yet very little is known about the pathogenesis of naturally occurring RHDV infections, and identification of the cellular receptor(s) used by the virus to establish infection would lead to a better understanding of the pathogenesis of RHDV.RHDV is known to agglutinate human erythrocytes (2, 25), and previous studies demonstrated that its hemagglutinin receptor on human red blood cells corresponds to a developmental antigen which is not expressed on fetal cells and is mainly carried by polyglycosylceramides (26). The glycolipid nature of the receptor on human red blood cells suggests that the carbohydrate moiety could be recognized by the virus capsid protein. Carbohydrate antigens of the histo-blood group family are developmental antigens that can be shared among various mammal species, and the presence of some of these antigens has been detected on epithelial cells of the rabbit digestive tract (1,17,21...

No abstract

A total of 50 Staphylococcus intermedius strains isolated in France from canine pyodermas in 2002 were investigated for their susceptibility to various antimicrobial drugs. Antimicrobial susceptibility was assessed using a 2-fold serial dilution method in Mueller-Hinton agar, and the minimal inhibitory concentrations (MICs) were determined. About 62% of the 50 strains tested were producers of beta-lactamase and categorized as penicillin-resistant. About 26% demonstrated resistance to sulphonamides, 46% to oxytetracycline, 30% to chloramphenicol, 28% to streptomycin, kanamycin, neomycin or erythromycin, 22% to clindamycin, 6% to doxycycline, 2% to gentamicin, enrofloxacin, marbofloxacin or pradofloxacin. Acquired resistance was not observed to a clavulanic acid-amoxicillin combination, oxacillin, cephalosporins (cephalexin, ceftiofur and cefquinome), trimethoprim, a sulphamethoxazole-trimethoprim combination and florfenicol. About 42% were simultaneously resistant to three or more antimicrobial classes (multiresistance). All isolates with acquired resistance to erythromycin were also resistant to streptomycin and neomycin/kanamycin. About 22% of isolates exhibited cross-resistance between erythromycin and clindamycin and all clindamycin-resistant isolates also exhibited resistance to erythromycin. Resistance to penicillin, oxytetracycline and chloramphenicol was also positively associated with resistance to erythromycin and streptomycin.

The efficacy of three feline leukaemia virus (FeLV) vaccines was compared. Kittens were immunised with either a recombinant subunit vaccine, Leucogen, or one of two inactivated virus vaccines, Leukocell 2 or Leucat. On subsequent challenge by intraperitoneal inoculation of FeLV of subgroup A (FeLV-A), only Leucogen gave significant protection. In a second experiment, kittens vaccinated with Leucogen were protected against oronasal challenge with a phenotypic mixture of FeLV of subgroups A, B and C. These results indicate that a recombinant vaccine, containing only the protein moiety of the surface glycoprotein of FeLV-A, can provide better protection than the inactivated virus vaccines tested against challenge with virus of the same subgroup, and can also protect against challenge by all three subgroups of FeLV.

No abstract

This study provides the first report of a floR-carrying plasmid in the genus Aeromonas and the first description of a tetR-tet(Y) determinant. The analysis of the multiresistant A. bestiarum strain indicates that strains of this species, some of which are opportunistic pathogens for fish, might also act as a resistance gene reservoir in the freshwater environment.

Aims:  The aims of this study were: (i) to determine the proportions of Aeromonas spp. resistant to florfenicol (FC), oxolinic acid (OA) and oxytetracycline (OTC) along a river receiving effluents from fish farms, and (ii) to assess the relevance of using this bacterial group as an indicator for studying the consequences of the use and release of these aquacultural antimicrobials in the freshwater environment, as compared with performing antimicrobial measurements in sediments. Methods and results:  Sediment interstitial waters sampled along a river during two distinct climatic seasons were plated on an Aeromonas‐selective medium supplemented or not with OA, OTC or FC. The October 2004 campaign showed an enrichment of OA‐ and OTC‐resistant Aeromonas immediately downstream of the fish farms and a wastewater treatment plant. Two fish farms showed similar results in March 2005. In contrast, only 10 FC‐resistant Aeromonas strains could be isolated, which revealed that minimum inhibitory concentrations of FC were greater than 64 μg ml−1 and multiple antimicrobial resistances. Contamination of sediments by antimicrobials was detected but was not always co‐localized with resistance peaks or known point sources of contamination. Conclusions:  Aeromonas could be valuable indicators of OA, OTC and FC resistance in the freshwater environment. Fish farms contribute to the contamination of the river by antimicrobials and resistant bacteria. Significance and Impact of the Study:  Considering the still very low proportion of FC‐resistant Aeromonas, this study can be considered as a reference for further studies about this recently introduced veterinary antimicrobial agent.

A. Thébault (10) , A.M. Hattenberger (2) & B. Toma (11) (1) Unité sous contrat (USC) École nationale vétérinaire d'Alfort (ENVA)/Agence nationale de sécurité sanitaire (Anses)-Epidémiologie des maladies animales infectieuses (EPIMAI), École nationale vétérinaire d'Alfort, 7 avenue du Général de Gaulle, 94700 Maisons-Alfort Cedex, France (2) Unité de l'évaluation des risques liés à l'alimentation et à la santé animales (UERASA), Agence nationale de sécurité sanitaire (Anses)-Direction de l'évaluation des risques (DER), 27-31 avenue du Général Leclerc,