Naringenin interferes with the dispersal of Staphylococcus aureus biofilms.

LOMBARTE SERRAT, A; DOTTO C; SULIGOY M; CERVINI BOHM G; SAENZ D; SORDELLI D; GIACOMODONATO M; BUZZOLA F

Ciudad Autónoma de Buenos Aires

Congreso; Reunión conjunta de Sociedades de Biociencias; 2017

Reunión conjunta de Sociedades de Biociencias (SAIC y otras)

Staphylococcusaureus biofilmsare recalcitrant to antibiotic treatment leading to chronicinfections. The final benefit to thebiofilm development is the potential for seeding dispersal or cellulardetachment. The dispersal mechanism requires an active agr quorum sensing system and occurs in a protease-dependentmanner. Naringenin (N) is a natural flavanone with antioxidant andantimicrobial properties. The aim of this study was to investigate the effectof N on S. aureus biofilm. S. aureus AR411 (osteomyelitis isolate related to USA300clone) and SH1000 laboratory strain were used. Citotoxicity using LM2 cell line was determined by MTT assay. Bacteriawere treated with N before biofilm formation takes place (prior-to-exposure)and 24 h after biofilms were formed (post-exposure). Biofilms were spectrophotometrically quantified. Inhibitionof agr system was monitoredfluorometrically. Proteolytic activity was assessed using milk agar plates. N (50µg/ml) did not affect the epithelial cells viability. The ability to formbiofilm by AR411 strain (prior-to exposure) significantly diminished inpresence of N (AR411: 3.27±0.11vs AR411+N: 1.64±0.08, p<0.01, t-test). The percentages of dispersalof AR411 and SH1000 biofilms were 83% and 64%, respectively. However, theaddition of N to mature biofilms (post-exposure) induced high biomass in bothstrains (AR411: 0.57±0.03vs AR411+N: 1.42±0.08,p<0.01; SH1000: 0.45±0.11vs SH1000+N: 2.03±0.16,p<0.01). The activation of agrsystem was inhibited by N (F/DO: 521; C+: 3777 and C-: 572). Supernatants of AR411mature biofilms treated with N did not show proteolytic activity. Altogetherthe results indicate that N reduced the ability to form biofilm by S. aureus USA300-like strain. Thedispersal mechanism was negatively affected by N due to the inhibition of agr system. Therefore, mature biofilmsincreased in presence of N as a result of absence of proteases.