Role of polysaccharide intercellular adhesin in adhesion of Staphylococcus aureus to human epithelial cells

• Main Authors: Li Ping Lin, 林莉萍
• Other Authors: M. H. Lin
• Format: Others
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/05043752036173535955

碩士 === 長庚大學 === 醫學生物技術暨檢驗學系 === 100 === Staphylococcus aureus is an important nosocomial pathogen. The ability to adhere and subsequently form biofilms on indwelling devices facilitates the development of chronic infections. During biofilm formation, S. aureus produces polysaccharide intercellular adhesin (PIA) which is synthesized by enzymes encoded by the ica operon. In addition to the involvement of biofilm formation in attachment and bacterial aggregation, several studies have demonstrated that PIA contributes significantly to cellular adherence. This study finds that S. aureus SA113Δica which is defective in PIA production adheres less efficiently to human epithelial cells than does the wild-type strain, S. aureus SA113. However, PIA production also affects the adhesion of S. aureus SA113 to host cells. When the SA113Δica mutant was complemented with pGicaΔR, which carries the wild type ica genes, the adherence of S. aureus Δica to host cells is partially restored. Moreover, when S. carnosus TM300, a PIA-negative and non-adherent strain, is introduced with a PIA-expressing plasmid, PIA production, biofilm formation and cellular adherence of the bacteria strain increases. In addition, adding PIA purified from S. aureus SA113 to the culture medium also enhances the adherence of S. carnosus TM300 to epithelial cells. Furthermore, PIA-mediated adhesion of S. aureus may not involve the extracellular matrix. These results from the study indicated that PIA is critical to the adhesion of S.aureus to human epithelial cells. This study reveals a mechanism that is important to understanding of the adhesion and invasion of S. aureus.