The effect of bovine milk-derived extracellular vesicles on the biofilm of staphylo-coccus aureus
10.16303/j.cnki.1005-4545.2025.11.17
- VernacularTitle:牛乳源细胞外囊泡对金黄色葡萄球菌生物被膜的影响
- Author:
Ziqiang GAO
1
;
Zi WANG
1
;
Peng LIU
1
;
Yangyang SONG
1
;
Xiaolin LI
1
;
Huaxue SONG
1
;
Binglei SHEN
1
Author Information
1. 黑龙江八一农垦大学动物科技学院,黑龙江大庆 163319
- Publication Type:Journal Article
- Keywords:
mastis milk extracellular vesicles;
Staphylococcus aureus;
biofilm;
gene expression
- From:
Chinese Journal of Veterinary Science
2025;45(11):2430-2438
- CountryChina
- Language:Chinese
-
Abstract:
The objective of this experiment was to investigate the inhibitory effect and mechanism of mammary-derived extracellular vesicles(MmEVs)from mastitis dairy cows on the biofilm for-mation of Staphylococcus aureus SA1.The biofilm-forming ability of Staphylococcus aureus SA1 was confirmed using Congo red staining,and the biofilm growth curve of S.aureus SA1 was plot-ted using the crystal violet staining method.The minimum inhibitory concentration(MIC)and minimum biofilm inhibitory concentration(MBIC)of MmEVs against S.aureus SA1 were deter-mined.After treating S.aureus SA1 with different concentrations of MmEVs,the cell morphology of S.aureus SA1 was observed using transmission electron microscopy.The effects of MmEVs on S.aureus SA1 under low pH(pH value=5)or heat stress(58℃)were investigated.The hydro-phobicity index was explored using the microbial adhesion to hydrocarbons(MATH)assay.Bacte-rial conductivity was measured.The expression levels of biofilm-related genes(SarA,icaB,FnbA,ClfB,CidA,and gyrB)were detected using quantitative real-time PCR(qPCR).The results showed that MIC of MmEVs against the biofilm of S.aureus SA1 was 1 000 mg/L,and the MBIC was 500 mg/L.Under the influence of MmEVs,the internal substances of S.aureus SA1 leaked,the biofilm boundary became blurred,and the cell wall separated.At the MBIC concentration,MmEVs significantly reduced the tolerance of S.aureus SA1 to low pH(P＜0.001)and high tem-perature(P＜0.001),decreased hydrophobicity(P＜0.001),and increased bacterial conductivity(P＜0.001).At the MBIC concentration,MmEVs significantly downregulated the gene expression of Sa rA(P＜0.001),icaB(P＜0.001),FnbA(P＜0.001),ClfB(P＜0.001),and CidA(P＜0.001)in S.aureus SA1,while no significant effect was observed on the expression of the gyrB gene.In summary,MmEVs inhibit the formation of Staphylococcus aureus SA1 biofilms by sup-pressing the gene expression of SarA,icaB,FnbA,ClfB,and CidA within the biofilm.This dis-ruption damages the biofilm's morphological structure,reduces its tolerance to low pH and high temperature,decreases hydrophobicity,and increases bacterial conductivity,thereby ultimately in-hibiting the formation of S.aureus SA1 biofilms.
