Genetic diversity of Actinobacillus lignieresii isolates from different hosts

Genetic diversity detected by analysis of amplified fragment length polymorphisms (AFLPs) of 54 Actinobacilus lignieresii isolates from different hosts and geographic localities is described. On the basis of variances in AFLP profiles, the strains were grouped in two major clusters; one comprising strains isolated from horses and infected wounds of humans bitten by horses and another consisting of strains isolated from bovine and ovine hosts. The present data indicate a comparatively higher degree of genetic diversity among strains isolated from equine hosts and confirm the existence of a separate genomospecies for A. lignieresi-like isolates from horses. Among the isolates from bovine and ovine hosts some clonal lines appear to be genetically stable over time and could be detected at very distant geographic localities. Although all ovine strains investigated grouped in a single cluster, the existence of distinct genetic lineages that have evolved specificity for ovine hosts is not obvious and needs to be confirmed in other studies

Sygdomme og velfærd

Siden anden verdenskrig er der sket store ændringer i fjerkræproduktionen. Indførslen af nye produktionssystemer, robuste og højtydende dyr, forbedret management og indførslen af biosecurity har medført en stor produktionsfremgang med lav mortalitet. I de senere år har forbrugerønsker medført at udvikling af udendørs produktionssystemer, hvor de klassiske fjerkræsygdomme nu er på fremmarch med en forhøjet mortalitet til følge. Forfatterne diskuterer, om de udendørs produktionssystemer reelt har betydet en forbedret velfærd for hønerne

Recombinant proteins from Gallibacterium anatis induces partial protection against heterologous challenge in egg-laying hens

International audienceAbstractGallibacterium anatis is a Gram-negative bacterium and major cause of salpingitis and peritonitis in egg-laying hens, thereby contributing to decreased egg production and increased mortality among the hens. Due to widespread drug resistance and antigenic diversity, novel prophylactic measures are urgently required. The aim of the present study was to evaluate the cross-protective capacity of three recombinant proteins recently identified as potential vaccine candidates; GtxA-N, GtxA-C, and FlfA, in an in vivo challenge model. Nine groups of birds were immunized twice with each protein, respectively, with 14 days separation. Additionally, three groups served as non-immunized controls. After 3 weeks, the birds were challenged with either of three G. anatis strains: 12656-12, 7990 or IPDH 697-78, respectively. Blood samples were taken at three different time points prior to challenge, as well as 48 h after challenge. All birds were euthanized and subjected to a post mortem procedure including scoring of lesions and sampling for bacterial growth. Moreover, ELISA assays were used to quantify antigen-specific IgG titers in serum. The results showed that all three proteins induced protection against the homologous strain 12656-12. No protein induced complete protection against strain 7990, although FlfA reduced the bacterial re-isolation rate. Moreover, immunization with GtxA-N and FlfA induced protection, while GtxA-C reduced the bacterial re-isolation, against strain IPDH 697-78. Thus although complete cross-protection against all three strains was not achieved, the results hold great promise for a new generation of immunogens in the search for novel prophylactic measures against G. anatis

QUINOLONE- AND ETA-LACTAM- RESISTANCE IN Escherichia coli FROM DANISH AND ITALIAN BROILER FLOCKS

The prevalence of quinolone- and -lactam-resistant E. coli was investigated among healthy broiler flocks in Denmark and Italy. In Denmark, sock samples were collected from 10 parent flocks and 10 offspring flocks, according to the procedure currently used for the surveillance of Salmonella in the EU. Samples were enriched in McConkey broth and streaked on McConkey agar plates added with nalidixic acid (32 g/ml), ciprofloxacin (2 g/ml), ampicillin (32 g/ml), cefotaxime (2 g/ml) or ceftiofur (8 g/ml). The -glucuronidase test was performed for verification of presumptive E. coli. The same methods were used to analyse sock samples collected from 6 Italian broiler flocks. PCR with primers for the CTX-M-type extended-spectrum -lactamases (ESBLs) was performed on cephalosporin-resistant isolates. While resistance to ampicillin and nalidixic acid was widespread in both countries, resistance to ciprofloxacin and cephalosporins was more common among Italian flocks. In Denmark, ciprofloxacin resistance was only detected in 1 parent flock without any history of quinolone usage and none of the flocks was positive for cephalosporin-resistant E. coli. In Italy, resistance to ciprofloxacin was detected in all flocks and resistance to ceftiofur and cefotaxime were detected in 5 flocks. Primers specific for the CTX-M-type ESBLs generated PCR amplicons from isolates from 3 of these flocks. In industrialized countries, the poultry production system is highly standardized, and therefore comparable. However, the use of broad-spectrum antimicrobials is particularly limited in Danish poultry production. Accordingly, the results of this study could reflect the different policies in antimicrobial usage between the two countries

Seroprevalence of Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum in Danish horses

<p>Abstract</p> <p>Background</p> <p><it>Borrelia burgdorferi </it>sensu lato and <it>Anaplasma phagocytophilum </it>are able to infect horses. However, the extend to which Danish horses are infected and seroconvert due to these two bacteria is unknown. The aim of the present study was to evaluate the seroprevalence of <it>B. burgdorferi </it>sensu lato and <it>A. phagocytophilum </it>in Danish horses.</p> <p>Methods</p> <p>A total of 390 blood samples collected from all major regions of Denmark and with a geographical distribution corresponding to the density of the Danish horse population were analyzed. All samples were examined for the presence of antibodies against <it>B. burgdorferi </it>sensu lato and <it>A. phagocytophilum </it>by the use of the SNAP^®4DX ^®ELISA test.</p> <p>Results</p> <p>Overall, 29.0% of the horses were seropositive for <it>B. burgdorferi </it>sensu lato whereas 22.3% were seropositive for <it>A. phagocytophilum</it>.</p> <p>Conclusions</p> <p>Antibodies against <it>B burgdorferi </it>sensu lato and <it>A. phagocytophilum </it>are commonly found among Danish horses thus showing that Danish horses are frequently infected by these organisms.</p

Further evidence of Chelonid herpesvirus 5 (ChHV5) latency : High levels of ChHV5 DNA detected in clinically healthy marine turtles

The Chelonid herpesvirus 5 (ChHV5) has been consistently associated with fibropapillomatosis (FP), a transmissible neoplastic disease of marine turtles. Whether ChHV5 plays a causal role remains debated, partly because while FP tumours have been clearly documented to contain high concentrations of ChHV5 DNA, recent PCRbased studies have demonstrated that large proportions of asymptomatic marine turtles are also carriers of ChHV5. We used a real-time PCR assay to quantify the levels of ChHV5 Glycoprotein B (gB) DNA in both tumour and non-tumour skin tissues, from clinically affected and healthy turtles drawn from distant ocean basins across four species. In agreement with previous studies, higher ratios of viral to host DNA were consistently observed in tumour versus non-tumour tissues in turtles with FP. Unexpectedly however, the levels of ChHV5 gB DNA in clinically healthy turtles were significantly higher than in non-tumour tissues from FP positive turtles. Thus, a large proportion of clinically healthy sea turtle populations worldwide across species carry ChHV5 gB DNA presumably through persistent latent infections. ChHV5 appears to be ubiquitous regardless of the animals' clinical conditions. Hence, these results support the theory that ChHV5 is a near ubiquitous virus with latency characteristics requiring co-factors, possibly environmental or immune related, to induce FP

Occurrence of haemolytic Mannheimia spp. in apparently healthy sheep in Norway

<p>Abstract</p> <p>Background</p> <p>The occurrence of <it>Mannheimia </it>species in healthy sheep has only been investigated to a very limited extend since the genus and its five named species were established. The aim of the present study was to evaluate the occurrence of haemolytic <it>Mannheimia </it>species in apparently healthy sheep originating from four sheep flocks in South-Western Norway.</p> <p>Methods</p> <p>Typical <it>β</it>-haemolytic <it>Pasteurellaceae </it>were isolated from nasal swabs and subsequently subjected to bacteriological examination. A total of 57 <it>Mannheimia </it>isolates were obtained in pure culture. All isolates were genotyped by amplified fragment length polymorphisms (AFLP) analysis and compared to six reference strains. The 16S rRNA gene sequences of two isolates were also determined.</p> <p>Results</p> <p><it>β</it>-haemolytic <it>Mannheimia </it>species were isolated from 24% to 64% of the sheep in the four flocks. A total of 26 haemolytic <it>M. ruminalis</it>-like strains were isolated among which, a considerable genetic diversity was found. Eighteen <it>M. glucosida </it>isolates were obtained from three flocks, whereas <it>M. haemolytica </it>was only isolated from two flocks, 16 of them being from only one of the flocks.</p> <p>Conclusion</p> <p>We demonstrate that a relatively high number of apparently healthy sheep in Norway seem to carry the potentially pathogenic <it>M. haemolytica </it>and <it>M. glucosida </it>in the upper respiratory tract. An unexpectedly high number of haemolytic <it>M. ruminalis</it>-like organisms were also obtained in all four flocks. The usually non-haemolytic <it>M. ruminalis </it>are typically isolated from healthy ruminants. The significance of <it>β</it>-haemolytic <it>M. ruminalis</it>-like organisms is unknown and should be investigated in a future study.</p