Effect of Ultraviolet Light on the Expression of Gene in Local Isolates in Iraq.

The current study was designed to reveal the impact of ultraviolet (UV) light on polysaccharide intercellular adhesion of the gene expression and its relation to biofilm as virulence markers in Staphylococcus aureus. In total, 37 isolates of were gathered from various bacterial infection sources, and 26 isolates were definite to gene using the Polymerase Chain Reaction (PCR) technique. Prior to and after exposure to UV light, RNAs from the isolates were extracted which had strong biofilm formation by crystal violet staining assay, and they were then exposed to quantitative real-time PCR (qPCR). In vitro, the survival of isolates was evaluated after the exposition to several periods of the UV light power via counting the number of colonies. The results showed that the exposure to the UV light at 320 nm for 2, 4, 6, 8, and 10 min had inhibitory effects on the bacterial growth. The sub-lethal exposure time was 8 min. The rapid reduction of bacterial survival rates was associated with the increment irradiation time of UV power from 5 to 1.24 log10 CFU/ml. In general, down regulation of the gene expression was decreased upon exposure to the UV light which was used as a physical agent for controlling the bacterial infection and biofilm formation.