›› 2019, Vol. 46 ›› Issue (7): 2110-2118.doi: 10.16431/j.cnki.1671-7236.2019.07.028

• Clinical Veterinary Medicine • Previous Articles     Next Articles

Establishment of Model of Exudative Dermatitis of Piglets Infected with Clinical Isolated Staphylococcus hyicus

MA Xuanxuan1,2, REN Weike3, TENG Da1,2, CHI Jingjing3, WANG Xiumin1,2, DONG Zhimin3, MAO Ruoyu1,2, HAO Ya1,2, LI Xiuli3, WANG Jianhua1,2   

  1. 1. Gene Engineering Laboratory, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China;
    2. Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Areas, Beijing 100081, China;
    3. Tianjin Animal Science and Veterinary Research Institute, Tianjin 300381, China
  • Received:2019-01-31 Online:2019-07-20 Published:2019-07-22

Abstract:

In order to provide a target animal model of exudative dermatitis of piglet for exploring the pathogenesis and therapeutic reagents,in this study,the toxin type of isolated Staphylococcus hyicus 437-2 was identified by PCR and BLAST sequence alignment,its drug resistance was detected by disk diffusion method,and the clinical pathogenicity,minimum pathogenic concentration,pathogenesis and histopathological changes caused by the strain were analyzed by artificially infecting piglets with different concentrations of bacterial liquid.The results showed that the strain carried the ExhD virulence gene,which showed 99% gene sequence homology with the isolated Germany strain (GenBank accession No.:AM94662.1) and Russian isolate (GenBank accession No.:AM950188.1).The drug resistant assay displayed S.hyicus 437-2 was a multi-drug resistant strain,which showed resistance to penicillin,sulfamethoxazole,streptomycin,azithromycin,erythromycin,tetracycline,bacitracin and norfloxacin.And the pathogenicity test of S.hyicus 437-2 on piglets showed that the low dose group displayed dermatitis symptoms only at the injection site throughout the experimental period,while significant exudative dermatitis symptoms appeared in the middle and high dose groups after subcutaneous injection for 2 d,which showed detailedly as oily skin behind the ear,rough fur,a large piece of suede and yellow liquid exuded,and thick dark brown skin.The results of pathological sections showed that organs in the low dose group were not damaged,while the skin tissue displayed excessive keratinization on the ear skin,inflammatory cell infiltration,and no cell separation.Meanwhile,the piglets in the middle and high dose groups all showed a certain degree of damage,the cell epidermal layer of the skin appeared obvious cell separation.This results indicated that this strain had strong pathogenicity and could successfully replicate exudative dermatitis on piglets.In addition,this result further indicated that the minimum bacterium concentration required for the establishment of exudative dermatitis model was 1×109 CFU/mL.

Key words: piglet exudative dermatitis; Staphylococcus hyicus; exfoliative toxin; piglet exudative dermatitis model

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