Abstract:

Aim: Staphylococcus aureus is the most clinically important bacterium among Staphylococci, colonizing 15-36% of the entire population. Biofilm formation is an important virulence factor of S. aureus. Treatment of biofilm-associated S. aureus infections is difficult. This study aimed to investigate the effects of glucose, sucrose, and sodium chloride (NaCl) addition to seven different media on biofilm formation capacity of methicillin resistant S. aureus (MRSA) strains. Material and Method: Biochemical and molecular methods (spa, nuc, coa, and mecA PCR) were used to identify S. aureus strains. Cefoxitin resistance was determined by the agar disc diffusion method. Biofilm formation of the strains was investigated in 7 different media (Tryptone soya broth (TSB), TSB+1% sucrose, TSB+1% glucose, TSB+4% NaCl, Brain Heart Infusion broth (BHI), BHI+1% glucose, and BHI+4% NaCl) using the microplate test. The growth of strains in 7 different media was determined at 600 nm, and then 96-well microplates were stained with crystal violet and their biofilm formation abilities were determined by measuring absorbance values ​​at 590 nm. Results: In this study, 53 strains containing spa, nuc, coa, and mecA genes were identified as MRSA with resistance to cefoxitin. When biofilm formation was examined in seven different media using the microplate test, the biofilm formation ability of MRSA strains increased significantly with glucose and sucrose addition to TSB and BHI (P<0.05), while the addition of 4% NaCl decreased the biofilm formation (P<0.05). When the media were compared, it was determined that BHI increased bacterial growth and biofilm formation compared to TSB. Conclusion: It was concluded that the biofilm formation abilities of MRSA strains increased especially in the presence of glucose. The results showed that biofilm production capacity is affected by environmental factors, especially nutrient content in used media.

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