Salicylic Acid Diminishes Staphylococcus aureus Capsular Polysaccharide Type 5 Expression

• Published in: Infection and Immunity Vol. 78; no. 3; pp. 1339 - 1344
• Main Authors: Alvarez, Lucía P, Barbagelata, María S, Gordiola, Mariana, Cheung, Ambrose L, Sordelli, Daniel O, Buzzola, Fernanda R
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for Microbiology 01-03-2010; American Society for Microbiology (ASM)
• Subjects: Adhesins; Aspirin; Bacterial Capsules - metabolism; Bacterial Proteins - biosynthesis; Bacteriology; Biological and medical sciences; Capsular polysaccharides; Cell Line; Data processing; Enzyme Inhibitors - pharmacology; Epithelial cells; Epithelial Cells - microbiology; Fundamental and applied biological sciences. Psychology; Gene Expression Profiling; Gene Expression Regulation, Bacterial - drug effects; Humans; Metabolites; Microbiology; Miscellaneous; Molecular Pathogenesis; Polymerase chain reaction; Promoters; Reverse Transcriptase Polymerase Chain Reaction; Salicylic acid; Salicylic Acid - pharmacology; Serotypes; Staphylococcus aureus; Staphylococcus aureus - drug effects; Transcription; virulence factors; Virulence Factors - antagonists & inhibitors; Prostaglandin-endoperoxide synthase; Salicylic acid; Enzyme; Enzyme inhibitor; Immunity; Non steroidal antiinflammatory agent; Microorganism capsule; Analgesic; Antipyretic; Bacteria; Micrococcales; Micrococcaceae; Oxidoreductases; Salicylates; Antirheumatic agent; Polysaccharide; Staphylococcus aureus
• ISSN: 0019-9567; 1098-5522
• DOI: 10.1128/IAI.00245-09

Capsular polysaccharides (CP) of serotypes 5 (CP5) and 8 (CP8) are major Staphylococcus aureus virulence factors. Previous studies have shown that salicylic acid (SAL), the main aspirin metabolite, affects the expression of certain bacterial virulence factors. In the present study, we found that S. aureus strain Reynolds (CP5) cultured with SAL was internalized by MAC-T cells in larger numbers than strain Reynolds organisms not exposed to SAL. Furthermore, the internalization of the isogenic nonencapsulated Reynolds strain into MAC-T cells was not significantly affected by preexposure to SAL. Pretreatment of S. aureus strain Newman with SAL also enhanced internalization into MAC-T cells compared with that of untreated control strains. Using strain Newman organisms, we evaluated the activity of the major cap5 promoter, which was significantly decreased upon preexposure to SAL. Diminished transcription of mgrA and upregulation of the saeRS transcript, both global regulators of CP expression, were found in S. aureus cultured in the presence of SAL, as ascertained by real-time PCR analysis. In addition, CP5 production by S. aureus Newman was also decreased by treatment with SAL. Collectively, our data demonstrate that exposure of encapsulated S. aureus strains to low concentrations of SAL reduced CP production, thus unmasking surface adhesins and leading to an increased capacity of staphylococci to invade epithelial cells. The high capacity of internalization of the encapsulated S. aureus strains induced by SAL pretreatment may contribute to the persistence of bacteria in certain hosts.