The Efficacy of Nano Silver Sulfadiazine and Nano Benzalkonium Chloride on Heterotrophic Biofilms

Silver sulfadiazine and benzalkonium chloride are biocidal agents known to be effective against microorganisms. Although planktonic cells are easily affected by these agents, bacteria in the biofilm layer are more resistant to the same chemicals. Agents fixed on nanoparticles are reported to have higher antimicrobial activity against biofilm bacteria. The effects of nanotechnological disinfectants on biofilm bacteria vary with dose and time. Also, the type of surface on which these disinfectants are sprayed also changes their activity. The aim of the study was to investigate the efficacy of nano silver sulfadiazine and nano benzalkonium on mature heterotrophic biofilm bacteria. Stainless steel coupons were sprayed with nano benzalkonium chloride and nano silver sulfadiazine and were air-dried to cure for 24 hours, then the coupons were placed into the biofilm reactor. Bacterial counts in the biofilm layer were compared at monthly intervals against control coupons. Heterotrophic biofilms allowed to form naturally for 4 months, were analyzed by microbiological culture methods. The number of live and dead microorganisms were determined by DAPI–CTC staining using epifluorescence microscope. After the test periods, microbial culture and DAPI–CTC (live/dead) results were found significantly lower on disinfectant covered coupons. Furthermore, nano benzalkonium chloride was found to be significantly more effective against biofilm bacteria than nano silver sulfadiazine. The results were examined in order to observe biofilm formation on the surfaces covered with nano benzalkonium chloride and nano silver sulfadiazine compounds, to evaluate their use in industrial and clinical fields as effective disinfectants. Because these disinfectants are frequently used in industrial or clinical environments, results have made an important contribution to the manufacturers to focus on final version of the product.