Isolation, characterization and identification of antibiotic-resistant biofilm forming bacteria from East Kolkata...

The current study holds major socio-economic importance of East Kolkata Wetland (EKW) in India, a Ramsar site, presently under constant threat of anthropogenic wastes that could accelerate antibiotic resistance (AR). The underlying mechanism behind the spread of AR in EKW requires proper investigation. Towards this direction, we focused on the isolation of antibiotic resistant bacteria (ARB) from EKW with adequate characterization by employing biochemical, molecular and antibiotic sensitivity tests. Thus, water samplings were carried out and a total of 32 ARB were isolated from three different study sites at EKW by selective agar plating. The isolates exhibited diverse biochemical properties with multi-antibiotic resistance (MAR) index exceeding 0.2 against 14 antimicrobial agents. MAR is strongly linked with biofilm formation. For comprehensive understanding of MAR among the isolates, their biofilm forming ability was checked. Henceforth, 14 potent biofilm formers were identified by measuring the total biofilm biomass through crystal violet (CV) assay and light microscopy. Furthermore, extracellular polymeric substance (EPS), metabolic activity, auto-aggregation property along with their motility pattern also confirmed their strong biofilm forming ability. Considering their pathogenicity, few exhibited hemolytic activities. Subsequently, these potent biofilm formers were identified by 16S rRNA gene and phylogenetic approach. These biofilm forming ARB in waterbodies of EKW requires vigilant monitoring before it is recycled for household, aquaculture and agricultural activities. Hence this study requires attention from the viewpoint of Sustainable Developmental Goals (SDGs) particularly related to good health (SDG 3) in the context of ensuring clean, sanitary water (SDG 6) and managing life below water (SDG 14).

The online version contains supplementary material available at 10.1007/s13205-026-05012-6.