Production of exfoliative toxin by isolates of Staphylococcus hyicus from different countries.

A total of 218 isolates of Staphylococcus hyicus from pigs in eight countries (Belgium, Croatia, Germany, Japan, Korea, Slovenia, the uk and the usa) and 44 isolates from other animals in Belgium, India, Japan and the usa were examined for the genes encoding the exfoliative toxins ExhA, ExhB, ExhC and ExhD by multiplex pcr. The expression of the toxins was confirmed by immunoblot analysis, using monoclonal or polyclonal antibodies specific for each of the toxins. The porcine isolates were from pigs with exudative epidermitis, pigs with other lesions and from healthy pigs, and one or more of the toxins could be found among the isolates from the pigs in all the countries. Toxigenic strains of S hyicus were isolated from both healthy and diseased pigs, but the chance of isolating toxigenic strains from pigs with exudative epidermitis was greater than from pigs with other lesions or healthy pigs. Of the 44 isolates from other animal species, only one isolate, from a hare from Belgium, produced ExhB, and one isolate, from a cow with mastitis from Japan, produced ExhA.

Exudative epidermitis and porcine circovirus-2 infection in a Swedish SPF-herd.

An outbreak of exudative epidermitis (EE) among piglets in a Swedish SPF-herd initiated a survey for indications as to the cause of disease. The herd was established by caesarean section and has been closed to all new animal material, with the exception of semen for artificial insemination (AI). The study comprised serum samples from the SPF-herd over a 10-year period (n=109) and a close monitoring of animals in the herd during the period after the EE outbreak. Serum samples from conventional boars at the AI-station servicing the herd were also included (n=9). All serum samples were tested for antibodies to porcine circovirus-2 (PCV-2). In addition, 3-week-old piglets from three litters (n=24) farrowed close after the initial EE outbreak were closely monitored for clinical signs of skin disease, sampled for Staphylococcus hyicus, tested for antibodies to porcine parvovirus and in sequentially collected serum samples tested for interferon-alpha (IFN-alpha) and interleukin-6. The PVC-2 serology showed that animals in the herd were sero-negative at least until 2 months prior to the EE outbreak. During the period close after the EE outbreak the animals showed varying levels of antibodies to PCV-2 but all the tested animals had sero-converted 4 months later. The AI boars were also sero-positive to PCV-2 at the time of the EE outbreak. Animals in the SPF-herd remained sero-positive to PCV-2 during the following 7 years. In the monitored litters, one piglet had clinical EE and 15 piglets displayed defined erythemas on the abdomen. Fourteen of the piglets also had IFN-alpha in serum on one or more occasions during the study, indicating viral activity among the animals. S. hyicus was isolated from all of the piglets from the earliest sampling point (3 days of age) and onwards, irrespective of clinical signs. PCV-2 was isolated from lymph node tissue collected from one of the EE affected pigs.Further, increases in the number of stillborn piglets, small litters (<6 piglets) and repeat breeders could be correlated to the time of PCV-2 sero-conversion. Coincidence of active viral infection and sero-conversion to PCV-2 points to the virus as the cause of the EE outbreak and reproductive disturbances.

Chromosomal and extrachromosomal synthesis of exfoliative toxin from Staphylococcus hyicus.

Evidence for the existence of two molecular species of exfoliative toxin (ET) synthesized by Staphylococcus hyicus (SHET) under chromosomal and plasmid control is presented. Serological evidence that these molecular species of toxins are distinct from each other is given. The molecular weights of SHET from plasmidless strain P-1 (SHETA) and from plasmid-carrying strains P-10 and P-23 (SHETB) were almost equal. Both of the serotypes of SHET exhibited exfoliation in 1-day-old chickens. The plasmid-cured (P(-)) substrains (P-23C1 and P-23C2) of S. hyicus P-23 did not cause exfoliation in 1-day-old chickens, whereas P(-) substrains (P-10C1 and P-10C2) of strain P-10 caused exfoliation, but they decreased their exfoliative activity. These findings suggest that SHETB was synthesized along with SHETA by strain P-10, whereas the P-23 strain synthesized SHETB alone. The plasmid-carrying strain (P-23) as well as the plasmidless strain (P-1) exhibited the typical clinical signs of exudative epidermitis in pigs. However, plasmid-cured (P(-)) substrains of P-23 (P23C1 and P23C2) did not exhibit the typical clinical signs of exudative epidermitis. These findings suggest that SHETA is synthesized under chromosomal control and SHETB is synthesized under plasmid control and that SHET-producing strains can be divided into three groups: SHETA-producing strains, SHETB-producing strains, and strains producing both toxins.

Ulcerative glossitis and stomatitis associated with exudative epidermitis in suckling swine.

Thirty piglets 1 to 4 weeks old from five herds had epidermal, foot, conjunctival and renal lesions typical of exudative epidermitis. Ten piglets had a large central ulceration of the dorsum of the tongue. Three piglets had multiple erosions of the hard palate and one had mucoid degeneration of the urinary bladder epithelium and a thick viscous material in the renal pelvis, ureters and urinary bladder.