Sequence analysis of a RAPD band differentiating high and low virulence Staphylococcus aureus strains from rabbits.

RAPD typing revealed the presence of a nucleotide band in typical high virulence rabbit Staphylococcus aureus strains which was absent in low virulence strains and in an atypical high virulence strain. The nucleotide sequence of this band was determined. Primers within this sequence were developed and PCR products of eight typical high virulence, one atypical high virulence and nine low virulence rabbit S. aureus strains were sequenced. All low virulence strains and the atypical high virulence strain revealed a constant difference with the typical high virulence strains for nucleotide 377 of the 1055bp sequence. The eight typical high virulence strains possessed a guanine base on this site, while the other strains tested showed an adenine base. These findings support the hypothesis on the clonal origin of typical high virulence rabbit S. aureus strains. After comparison with databases, two open reading frames (ORF) were identified within the sequence, which appeared to encode two structural ribosomal proteins. The single nucleotide mutation does not affect the amino acid sequence of the protein it encodes for.     

Colonization of rabbits with Staphylococcus aureus in flocks with and without chronic staphylococcosis.

Rabbits of 19 rabbitries were examined for the presence of Staphylococcus aureus in nine different body sites. Seven rabbitries experienced epidemically spreading signs of staphylococcosis while the other 12 rabbitries did not. S. aureus was isolated in all seven flocks that suffered from chronic problems of staphylococcosis and in 11 of the 12 clinically healthy flocks. The mean percentage of infected animals in these two groups was 90 and 43.3%, respectively. S. aureus was isolated from all body sites examined, but the ear and the perineum were often more intensely colonized. The number of animals colonized with S. aureus and the mean number of positive body sites in S. aureus positive rabbits were significantly higher in rabbitries with chronic staphylococcosis. This indicates that colonization capacity of S. aureus plays a role in epidemically spreading disease in rabbits. S. aureus isolates belonged to five different biotypes and 23 different phage types. Several different types simultaneously circulated in contaminated rabbitries and even simultaneously infected individual rabbits. Strains that belonged to the biotype-phage type combination mixed CV-C, 3A/3C/55/71 only occurred in rabbitries chronically dealing with signs of staphylococcosis. This may indicate a relationship between phenotypic strain properties and virulence of S. aureus.     

Association of Streptococcus gallolyticus strains of high and low virulence with the intestinal tract of pigeons

We investigated the ability of a high virulence (STR 357) and a low virulence (STR 598) strain of Streptococcus gallolyticus to attach to the intestinal tract of pigeons. For that purpose, first of all, two groups of six pigeons were anesthetized and ligatures were placed at the beginning of duodenum, jejunum, ileum, and colon. The obtained intestinal loops of the birds of the first and second group were injected with S. gallolyticus strains STR 357 and STR 598, respectively. At 15, 30, and 60 min postinoculation, two pigeons of each group were euthanatized and the various intestinal loops were sampled for histologic, immunohistochemical, and electron microscopic examination. Both the high and low virulence strains were able to adhere to the intestinal mucosa. Indeed, all samples dearly showed numerous coccal-shaped bacteria that stained positively with S. gallolyticus antiserum and were lining up against the intestinal epithelium. Likewise, on electron microscopic examination, cocci were seen in the mucus covering the intestinal epithelium. Second, the association of S. gallyticus strains of differing virulence with the intestinal tissue was determined quantitatively. Experiments were performed as described above. The number of S. gallolyticus bacteria that adhered to the intestinal epithelium was determined by plating out 10-fold serial dilutions of the segments. No significant differences in the number of adhered bacteria were found between the strains of high and low virulence.     

Multiplex PCR assay for the detection of high virulence rabbit Staphylococcus aureus strains

High virulence rabbit Staphylococcus aureus strains, which are clonal in origin, are responsible for the spread of chronic staphylococcosis at the rabbit flock level. The aim of the present study was to develop a multiplex PCR assay that can be used for the identification of these high virulence strains. Two targets of the assay were the bbp and the selm genes, which have recently been shown to occur specifically in high virulence isolates. A third target was a sequence designated "flank", which was derived from a previously generated high virulence specific RAPD pattern. Furthermore, the femA gene, which is specific for S. aureus, was incorporated in order to avoid false negative results due to insufficient DNA preparation. The multiplex PCR was successful at differentiating the 26 typical high virulence and 50 low virulence rabbit S. aureus strains incorporated in the present study. Therefore it is useful for the initial screening of newly acquired breeding stock, in order to prevent the intake of high virulence strains in rabbitries.     

Influence of gallic acid and tannic acid on the mechanical and barrier properties of wheat gluten films

Vital wheat gluten, a byproduct of wheat starch production, is a highly functional ingredient having a unique viscoelasticity that makes it ideal for the production of edible biodegradable films. However, its functional properties must be modified to ensure sufficient strength and elasticity, in addition to water vapor barrier properties. In this study, vital gluten was modified using tannic and gallic acid. It was found that the addition of tannic acid resulted in stiffer, more resistant, and less resilient and flexible films, having as well decreased water vapor permeability. Tannic acid containing films became reddish brown, whereas gallic acid addition did not have an influence on the film appearance. Films containing gallic acid became more elastic. Gallic acid was found to potentially act like a plasticizer. Scanning electron microscopy was used to investigate the ultrastructure of the produced films.     

Helminth and protozoan parasites in dogs and cats in Belgium

This study investigates the level of helminthic and protozoal infestation over the last 10 years in strays, well-cared-for dogs and cats. Determination of the prevalence of infections was based either on faecal examination or on worm counts at necropsy. Of 2324 faecal flotations (NaCl sp.gr. 1.20) of stray dogs, 34.2% had eggs or proglottids of one or more worm species consisting of Toxocara canis (17.4%), Toxascaris leonina (10.1%), Uncinaria stenocephala (11.4%), Trichuris vulpis (7.0%) and cestodes (2.1%). Isospora oocysts were observed in 5.2% of the dogs. The data on the distribution of the various worm species in the positive dogs indicate that T. canis eggs were by far the most common (50.9%). Necropsy data from 212 infected dogs indicate that 38.9% were infected with T. canis and 33.7% with T. leonina. The overall prevalence of worm infestation of 246 well-cared-for kennel dogs, based on worm egg counts by the McMaster technique, was 36.1%. Of 30 feline faecal samples examined by flotation, 83.3% were positive for parasites, including Toxocara cati (60%), Ancylostoma tubaeformae (36.6%), Taenia (Hydatigera) taeniaeformis (20%) and coccidia (30%). Toxocara cati was the most frequently found worm species at the necropsy of 25 cats (52%). Toxoplasma was not observed.     

Characterization of two unknown compounds in methanol extracts of rosemary oil

In this study, two unknown compounds in rosemary oil, containing 3% carnosic acid and 0.3% carnosol, were identified and characterized. After methanol extraction, purification, and analysis by reversed-phase HPLC and LC-MS, a recovery of 92% (+/-8%) of carnosic acid was obtained, but no carnosol was found. However, two unknown compounds with a molecular weight of 330.2 and 302.2 were consistently detected. From additional LC-MS-MS, (1)H NMR, and elemental analyses, it became clear that the first compound (M(w) = 330.2) could not be carnosol. It was hypothesized that it originated from the breakdown of the intramolecular bond of carnosol, followed by the addition of a water molecule. Possibly, an unsaturated double bond was formed after dehydration. Assuming that this compound was an intermediate in the conversion to rosmanol, the second unknown compound (M(w) = 302.2) may have resulted from the breakdown of the intramolecular bond of rosmanol. Similarly, an unsaturated double bond may have been formed. After splitting off carbon oxide, a detectable molecule with a molecular weight of 302.2 was observed.     

Prevalence of genes encoding exfoliative toxins, leucotoxins and superantigens among high and low virulence rabbit Staphylococcus aureus strains

Staphylococcus aureus is an important cause of pododermatitis, subcutaneous abscesses and mastitis in rabbits. On rabbitry level, two types of S. aureus infections can be distinguished. In the first type, caused by low virulence strains, the infection affects only a small number of animals. The second type of infection is caused by high virulence strains and spreads throughout the rabbit flock. The pathogenic capacity of a particular S. aureus strain is attributed to a combination of invasive properties and extracellular factors such as toxin production. Therefore, 22 high virulence and 37 low virulence S. aureus isolates were compared regarding the prevalence of genes encoding exfoliative toxins, leucotoxins and superantigens. This study revealed a clearly significant difference between HV and LV rabbit S. aureus strains. All typical HV isolates were positive for the egc cluster, containing the enterotoxin(like) genes seg, sei, selm, seln, selo and selu, whereas these genes were not detected in any of the LV isolates. Further research is necessary to clarify the importance of the egc cluster in the pathogenesis of infections with high virulence S. aureus strains in rabbits.     

Prevalence of wet litter and the associated risk factors in broiler flocks in the United Kingdom

A postal questionnaire was sent to the managers of 857 broiler farms in the UK to determine the prevalence and risk factors for wet litter. The response rate was 75 per cent. Wet litter was reported by 75 per cent (95 per cent confidence interval [CI] 71.3 to 78.3) of the respondents in at least one flock during the year 2001 and 56.1 per cent (95 per cent CI 52.0 to 60.0) of them reported that they had an outbreak of wet litter in their most recently reared flock. Wet litter occurred more often during the winter months and farms using side ventilation systems were at an increased risk (odds ratio 1.74; 95 per cent CI 1.09 to 2.76). A multivariable analysis was carried out using two different definitions of wet litter as outcome variables - all cases of wet litter, and cases of wet litter associated with disease. Consistent risk factors for both outcomes were coccidiosis, feed equipment failures and the availability of separate farm clothing for each house. Cases of wet litter associated with disease were reported by 33.7 per cent (95 per cent CI 28.8 to 39.1) of the managers in their last flock and were associated with the use of hand sanitisers and broiler houses with walls made of concrete.     

The current status and future directions of myxoma virus, a master in immune evasion

ABSTRACT: Myxoma virus (MYXV) gained importance throughout the twentieth century because of the use of the highly virulent Standard Laboratory Strain (SLS) by the Australian government in the attempt to control the feral Australian population of Oryctolagus cuniculus (European rabbit) and the subsequent illegal release of MYXV in Europe. In the European rabbit, MYXV causes a disease with an exceedingly high mortality rate, named myxomatosis, which is passively transmitted by biting arthropod vectors. MYXV still has a great impact on European rabbit populations around the world. In contrast, only a single cutaneous lesion, restricted to the point of inoculation, is seen in its natural long-term host, the South-American Sylvilagus brasiliensis and the North-American S. Bachmani. Apart from being detrimental for European rabbits, however, MYXV has also become of interest in human medicine in the last two decades for two reasons. Firstly, due to the strong immune suppressing effects of certain MYXV proteins, several secreted virus-encoded immunomodulators (e.g. Serp-1) are being developed to treat systemic inflammatory syndromes such as cardiovascular disease in humans. Secondly, due to the inherent ability of MYXV to infect a broad spectrum of human cancer cells, the live virus is also being developed as an oncolytic virotherapeutic to treat human cancer. In this review, an update will be given on the current status of MYXV in rabbits as well as its potential in human medicine in the twenty-first century.Table of contentsAbstract1. The virus2. History3. Pathogenesis and disease symptoms4. Immunomodulatory proteins of MYXV4.1. MYXV proteins with anti-apoptotic functions4.1.1. Inhibition of pro-apoptotic molecules4.1.2. Inhibition by protein-protein interactions by ankyrin repeat viral proteins4.1.3. Inhibition of apoptosis by enhancing the degradation of cellular proteins4.1.4. Inhibition of apoptosis by blocking host Protein Kinase R (PKR)4.2. MYXV proteins interfering with leukocyte chemotaxis4.3. MYXV serpins that inhibit cellular pro-inflammatory or pro-apoptotic proteases4.4. MYXV proteins that interfere with leukocyte activation4.5. MYXV proteins with sequence similarity to HIV proteins4.6. MYXV proteins with unknown immune function5. Vaccination strategies against myxomatosis5.1. Current MYXV vaccines5.2. Vaccination campaigns to protect European rabbits in the wild6. Applications of myxoma virus for human medicine6.1. MYXV proteins as therapeutics for allograft vasculopathy and atherosclerosis6.2. Applications for MYXV as a live oncolytic virus to treat cancer7. Discussion and Conclusions8. List of AbbreviationsReferencesAuthor DetailsAuthors' contributionsCompeting interestsFigure LegendsAcknowledgements.