A Highly Pathogenic Strain of Staphylococcus sciuri Caused Fatal Exudative Epidermitis in Piglets

Abstract

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 1×1010 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.

Critical roles of amino acids Ser231, His107 and Asp156 of Staphylococcus sciuri exfoliative toxin C (ExhC) in the induction of skin exfoliations in neonate mice

“…It has been reported that some pathogenic strains of S. sciuri are responsible for mastitis in ruminants such as goats (Poutrel 1984) and cows (Rahman et al 2005), suggesting that some members of S. sciuri are potentially pathogenic. In our previous study, we reported that a strain S. sciuri HBXX06 with ExhC as a major toxin was highly pathogenic to piglets (Chen et al 2007).…”

“…From S. hyicus, a commonly seen causative agent for EE, four exfoliative toxins (ExhA-D) have been characterized (Ahrens & Andresen 2004). Although certain strain of S. hyicus code for more than one exfoliative toxins (Andresen 2005), ExhC is the only exfoliative toxin encoded by S. sciuri HBXX06 strain (Chen et al 2007). In our previous study, we found that the ExhC (GenBank accession No.…”

“…ExhC was the only exfoliative toxin harboured in S. sciuri HBXX06 responsible for EE in piglets (Chen et al 2007). To investigate the role of ExhC in the pathogenesis of EE, we predicted three-dimensional structure of ExhC using SWISS-MODEL (http://swissmodel.…”

“…Exudative epidermitis (EE) in pigs results from infection with exfoliative toxin-producing strains of Staphylococcus hyicus (Andresen et al 1993) and Staphylococcus sciuri (Chen et al 2007). EE is characterized by exfoliated epidermis accompanied by extensive exudation and crust formation.…”

“…To explore the pathogenicity of S. sciuri strain HBXX06, we predicted the three-dimensional structure of ExhC, the only exfoliative toxin produced by S. sciuri HBXX06 (Chen et al 2007), obtained the mutant ExhC by replacing Ser231 or His107 or Asp156 in the active site of ExhC, and examined the activity of mutant ExhC using BHK-21 cells and newborn mice as models. We found that mutant ExhC lost its exfoliative effects on newborn mice but could still induce necrosis in cultured cells if any one of amino acid residues in the active site was replaced.…”