Biochemical and Molecular Characterization of Biofilm Producing Escherichia coli Isolated from Clinical Specimens in Irrua Specialist Teaching Hospital, Irrua Edo State

Escherichia coli, like many bacteria with the ability to form biofilm, can withstand stress in its environment to evade the host defence mechanisms and even antimicrobial agents. The biochemical and molecular characterisation of biofilm-producing Escherichia coli isolated from clinical specimens within Ekpoma and its environs was analysed to isolate E. coli, detect their biofilm-forming capacity(s), and demonstrate their biofilm-forming and antibiotic resistance genes. Two methods were used to establish biofilm production, the Congo red agar (CRA) and microtitre plate methods. This gave a reproducibility of about 90%. Clinical isolates had stronger biofilm formers of 25.7% with a percentage of weak formers (17.1%). Antibiotic resistance was low before biofilm formation but increased by 61.5% after biofilm formation. Molecular characterisation tests revealed plasmid-encoded fimbriae H (fim h) and aggregate genes [(agg) 3IV] for biofilm formation for strong, moderate and weak formers only from both sources of isolates. The presence of plasmids for biofilm formation made multidrug resistance of commonly used antibiotics possible in their normal routine dosages. This was further established by the presence of antibiotic-resistance genes for quinolones and aminoglycosides. Biofilm-forming isolates were further tested with 75ul/g of acrydine orange (AO) dye for plasmid curing. Results showed a drop in biofilm formation from about 90% to 9.9%, and antibiotic resistance from 78.6% to 10.0%. Plasmid-mediated antibiotic resistance can be attributed to the widespread use of antimicrobial agents and self-medication which is of great concern for public health and a great threat to chemotherapy and medicine worldwide.