Screening and evaluation of Biofilm forming antibiotic-resistant bacterial strains isolated from wastewater treatment plants and river environment

This study aimed to assess the antibiotic resistance and biofilm formation efficiency in different bacterial strains isolated from wastewater treatment plants (WWTPs) and Ganges River environments of three North Indian cities in summer and winter. A total of 104 morphologically distinct bacterial strains were isolated from wastewater and river samples and molecularly characterized by 16S rRNA gene sequencing. All bacterial strains showed multidrug resistance against the most commonly used antibiotics. The biofilm formation ability of bacterial strains was evaluated through the crystal violet method. According to the results, 54.38% of bacterial isolates were strong biofilm formers isolated in the summer season, whereas 35.41% isolated in the winter were strong biofilm formers after 72 hours of incubation. Among the biofilm-forming bacterial isolates, the highest autoaggregation index was observed in Kerstersia gyiorum (summer) and Bacillus cereus (winter). However, some bacterial strains capable of biofilm formation showed no aggregation properties. Thus, the present study showed that multidrug-resistant bacterial strains isolated from wastewater and river environments can form biofilm. Also, this study suggested the development of innovative bioinocula in antibiotic degradation and preventing biofilm development.