Autogenous vaccination reduces antimicrobial usage and mortality rates in a herd facing severe exudative epidermitis outbreaks in weaned pigs.

This study was conducted in a commercial 1000-sow herd facing recurrent exudative epidermitis (EE) outbreaks during the nursery period and assessed the efficacy of autogenous vaccination in controlling such outbreaks. The vaccine was produced using three Staphylococcus hyicus isolates recovered from affected pigs shortly before the onset of the study. All of those isolates were positive for the exhB gene, which encodes the exfoliative toxin type B (ExhB). From four consecutive farrowing batches of sows, two batches were vaccinated (V) against S hyicus at five and two weeks before farrowing, and two sow batches remained non-vaccinated (NV). Vaccination efficacy was primarily determined by the levels of metaphylactic antimicrobial usage, and the morbidity and mortality data for the pigs of the V and NV sows. The total amount of antimicrobials used metaphylactically against EE in pigs among the V and NV farrowing batches was 39,600 and 88,550 mg, respectively. The used daily dose pig to animal daily dose pig ratio for the V and NV batches were 1.31 and 1.79, respectively (a ratio of 0.8 to 1.2 is indicative of correct dosing). The morbidity and mortality rates were V=6.50 and NV=14.36 (P=0.008), and V=2.59 and NV=5.02 (P=0.000), respectively. To conclude, autogenous vaccination of the sows with a vaccine based on exhB-positive S hyicus isolates reduced metaphylactic treatment with antimicrobials as well as the morbidity and mortality rates in weaned pigs compared with pigs from NV sow batches.

A highly pathogenic strain of Staphylococcus sciuri caused fatal exudative epidermitis in piglets.

Staphylococcus sciuri are important human pathogens responsible for endocarditis, peritonitis, septic shock, urinary tract infection, pelvic inflammatory disease and wound infections. However, little information is known regarding the pathogenicity of S. sciuri to animals. From the pericardial fluid of a diseased piglet with exudative epidermitis (EE), we isolated a strain of Staphylococcus in pure culture. Surprisingly, this isolate was a member of S. sciuri rather than S. hyicus as identified by its biochemical traits and also by analysis of 23S ribosomal DNA using Internal Transcribed Spacer PCR. In addition, inoculation of newborn piglets with 1x10(10) CFU of the isolate by oral feeding or intra-muscular injection successfully reproduced EE in piglets, which suggested that the oral intake of the pathogen by the animals is one of the major routes of exposure. These unexpected findings prioritized S. sciuri as important zoonotic agents, which may have ramifications for human medicine.