Antimicrobial Activities of the Polypropylene Imine Dendrimer Aginst Bacteria Isolated From Rural Water Resources

Background: Dendrimers are a new class of polymeric materials with the well-defined structure, composition and architecture. Owing to antibacterial properties of dendrimers, they can be used as alternative water and wastewater disinfection with the minimum adverse side effects. Objectives: The aim of the present study was to evaluate the antibacterial activity of second generation poly propylene imine (PPI- G2) dendrimer on predominant bacteria in drinking water resources. Materials and Methods: In this qualitative and interventional study, a total of 764 water samples were collected from rural areas in Qom Province, Iran, and bacteria were isolated and identified using standard procedures. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against gram-positive and gram-negative bacteria were determined according to clinical and laboratory standards institute (CLSI) guideline. Standard discs were prepared using different concentrations of dendrimer on Mueller- Hinton agar plates. Results: The most important isolated bacteria were Escherichia coli 37 (48.7%), Klebsiella oxytoca 12 (15.8%), Proteus mirabilis 3 (4%), Entrobacter aerogenes 8 (10.5%), Citrobacter freundii 4 (5.2%), Pseudomonas aeruginosa 5 (6.6%), Staphylococcus aureus 2 (2.6%), and Bacillus subtilis 5 (6.6%). Moreover, it was found that PPI-G2 showed more potent activity towards the gram-positive bacteria than the gram-negative ones. Conclusions: The PPI-G2 dendrimer with end amine groups exhibited a positive impact on the removal of dominant bacterial isolated strains. Therefore, it is possible to use these nanodendrimers as a safe and effective material for water disinfection in the future.