ACTA VETERINARIA ET ZOOTECHNICA SINICA ›› 2018, Vol. 49 ›› Issue (3): 629-636.doi: 10.11843/j.issn.0366-6964.2018.03.021

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Effect of Andrographolide on the Biofilm Formation of Streptococcus suis

WANG Jin-yu1, JIANG Xiao-wen1, WANG Na1, WANG Jie-ran1, YU Miao-miao1, ZHONG Qiu1, YU Wen-hui1,2*   

  1. 1. College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, China;
    2. The Key Laboratory for the Prevention and Control of Common Animal Diseases in the Education Department of Heilongjiang Province, Harbin 150000, China
  • Received:2017-08-07 Online:2018-03-23 Published:2018-03-23

Abstract:

The aim of this study was to evaluate the inhibitory effect of Andrographolide on the Streptococcus suis. The dilution method was conducted to determine the minimum inhibitory biofilm formation of S. suis and to provide an alternative therapy for the drug resistance of concentration (MIC) and minimum bactericidal concentration (MBC) of Andrographolide on S. suis; The effects of Andrographolide on the biofilm formation of S. suis were detected by crystal violet staining (CV) and scanning electron microscopy (SEM). Result were as follows:1)The MIC and MBC of Andrographolide on S. suis were 0.25 and 0.5 mg·mL-1, respectively. 2)Scanning electron microscopy showed that the bacteria were embedded in the biofilm in the blank control group. Andrographolide(1/2MIC, 1/4MIC, 1/8MIC)can make the number of bacteria in the bacterial biofilm and the morphology of the biofilm changed greatly. According to the dose of the trend changed, bacterial biofilm gradually reduced. The results showed that Andrographolide had inhibitory effect on the formation of S. suis biofilm in a dose-dependent manner. 3)Through quantitatively detected the expression of luxS gene and virulence gene in S. suis by RT-PCR, we can see the sub-MICs (1/2MIC, 1/4MIC) of Andrographolide can respectively reduce the expression of gapdh, sly, fbps, ef and luxS genes and significantly increase the expression of cps2J, mrp, and gdh genes. 4)Detected the bacterial culture medium by Bioluminescence of Vibrio harveyi showed that Andrographolide (1/2MIC, 1/4MIC, 1/8MIC) had inhibitory effect on the production of AI-2 signal molecule in S. suis, in a dose-dependent manner. Intervention of Andrographolide can inhibit the formation of biofilm in S. suis, and can cause the difference of virulence gene expression levels.

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