Effects of probiotics and antibiotics on biofilms

Experiments were conducted to study the effects of probiotics and antibiotics on 3-months old biofilms formed on three different substrates, namely glass, granite and fiberglass reinforced plastic. The variations in heterotrophic bacterial populations associated with biofilms were monitored for a period of one month after one-time application of the probiotic Biogreen (Gee Key Marine Pvt. Ltd, Chennai) at 0.2 mg lˉ¹ and the antibiotic tetracycline at 1.0 mg lˉ¹. The variations in heterotrophic bacterial populations associated with biofilms were compared with that of control to analyse the effects of probiotics and antibiotics on biofilms. The observations showed that the biofilm formation and succession in aquatic environment is substrate dependent and that the resistance to antibiotics also depends on the substrate. The probiotics did not show significant effect on biofilms.