Role of DNase in combination with quinolones on stentrophomonas maltophila biofilm

Stentrophomonas maltophila [S. maltophila] biofilm plays a crucial role in its resistance to antibiotics. Extracellular DNA found to be an essential component of biofilm of different Gram positive and Gram negative bacteria. Its role in S. maltophila biofilm is not well established. This work assessed the role of destruction of extracellular DNA of S. maltophila biofilms in enhancing the antimicrobial effect of the used levofloxacin or ciprofloxacin. This study enrolled twenty three isolates of S. maltophila in which biofilm production and the presence of extracelular DNA in it were tested. The effect of two quinolone antibiotics [ciprofloxacin and levofloxacin] and DNAase each alone and in combination together on biofilm production were assessed on biofilm production and viable count. Our results showed that combined use of DNase with either ciprofloxacin or levofloxacin caused significant reduction of both biomass and viable count. In conclusion, the addition of DNase to quinolones boosts the antibiotic efficacy against S. maltophila biofilm