Unveiling the role of free DNA in biofilm formation; potential relevance in Cholera epidemiology

Abstract

This study meticulously probes the impact of both isogenic and heterogenic genomic DNA, in its entirety and fragmented states, on the density of biofilms formed by distinct bacterial strains, spanning both gram-positive and gram-negative classifications. Utilising samples from two distinct strains of Vibrio cholerae (WT346 and 1877), Escherichia coli (0157:H7), and Staphylococcus aureus (ATCC 25923), which were procured from the Life and Natural Sciences Laboratory at BRAC University, the formation and robustness of biofilms were quantitatively analysed via the crystal violet assay technique. Notably, biofilm density exhibited pronounced variations when exposed to isogenic genomic DNA as opposed to its heterogenic counterpart. Moreover, intact genomic DNA consistently elicited enhanced biofilm thickness relative to its fragmented variant, which elicited a more heterogeneous and attenuated response. Among the bacterial exemplars scrutinised, strain 1877 exhibited the most pronounced percentage augmentation in biofilm density in the presence of both fragmented (150%) and whole (125%) ATCC 25923 genomic DNA. This investigation underscores the nuanced interplay between genomic DNA and bacterial biofilm dynamics, offering pivotal insights for microbial ecology.