Crystal Violet and XTT Assays on Staphylococcus aureus Biofilm Quantification.
Staphylococcus aureus (S. Aureus) is a common food-borne pathogenic microorganism. Biofilm formation remains the major obstruction for bacterial elimination. The study aims at providing a basis for determining S. aureus biofilm formation. 257 clinical samples of S. aureus isolates were identified by routine analysis and multiplex PCR detection and found to contain 227 MRSA, 16 MSSA, 11 MRCNS, and 3 MSCNS strains. Two assays for quantification of S. aureus biofilm formation, the crystal violet (CV) assay and the XTT (tetrazolium salt reduction) assay, were optimized, evaluated, and further compared. In CV assay, most isolates formed weak biofilm 74.3 %), while the rest formed moderate biofilm (23.3 %) or strong biofilm (2.3 %). However, most isolates in XTT assay showed weak metabolic activity (77.0 %), while the rest showed moderate metabolic activity (17.9 %) or high metabolic activity (5.1 %). In this study, we found a distinct strain-to-strain dissimilarity in terms of both biomass formation and metabolic activity, and it was concluded from this study that two assays were mutual complementation rather than being comparison.
College of Food Science and Technology, South China University of Technology, Guangzhou, 510640, China. zhenbo.xu@hotmail.com.|Department of Biomedical Science, University of Maryland, Baltimore, MD, 21201, USA. zhenbo.xu@hotmail.com.|College of Light Industry and Food Science, South China University of Technology, 381 Wushan Road, Guangzhou, 510640, China. zhenbo.xu@hotmail.com.
Zhenbo
Z
Xu
College of Food Science and Technology, South China University of Technology, Guangzhou, 510640, China.
Yanrui
Y
Liang
College of Food Science and Technology, South China University of Technology, Guangzhou, 510640, China.
Shiqi
S
Lin
Department of Laboratory Medicine, First Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510120, China.
Dingqiang
D
Chen
College of Food Science and Technology, South China University of Technology, Guangzhou, 510640, China.
Bing
B
Li
College of Food Science and Technology, South China University of Technology, Guangzhou, 510640, China.
Lin
L
Li
College of Food Science and Technology, South China University of Technology, Guangzhou, 510640, China.
Yang
Y
Deng
D018441:Biofilms; D005840:Gentian Violet / Q000737:chemistry; D006801:Humans; D013194:Staining and Labeling / Q000379:methods*; D013203:Staphylococcal Infections / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology; D013778:Tetrazolium Salts / Q000737:chemistry
D013778:Tetrazolium Salts; D005840:Gentian Violet