The objective of this study was to elucidate the role of the icaA gene in biofilm formation of Staphylococcus aureus exposed to NaCl. The icaA-deletion mutant of S. aureus ATCC 13565 was constructed with the temperature-sensitive plasmid pIMAY. Microtiter plate assays were performed to confirm biofilm formation for both the wild type and the mutant at 0% (control), 2, 4, and 6% NaCl. The microtiter plate assay revealed that biofilm formation by the wild type increased ( P < 0.05) as NaCl concentration increased, but biofilm formation of the mutant was not affected by NaCl concentration. Biofilm formation by the mutant was lower ( P < 0.05) than that by the wild type. These results indicate that icaA plays an important role in biofilm formation by S. aureus when the pathogen is exposed to NaCl.
Keywords: Biofilm; NaCl; Staphylococcus aureus; icaA.