Impact of Plant Extracts and Antibiotics on Biofilm Formation of Clinical Isolates From Otitis Media

Background: Otitis media can lead to severe health consequences, and is the most common reason for antibiotic prescriptions and biofilm-mediated infections. However, the increased pattern of drug resistance in biofilm forming bacteria complicates the treatment of such infections. Objectives: This study was aimed to estimate the biofilm formation potential of the clinical isolates of otitis media, and to evaluate the efficacy of antibiotics and plant extracts as alternative therapeutic agents in biofilm eradication. Materials and Methods: The ear swab samples collected from the otitis media patients visiting the Mayo Hospital in Lahore were processed to isolate the bacteria, which were characterized using morphological, biochemical, and molecular (16S rRNA ribotyping) techniques. Then, the minimum inhibitory concentrations (MICs) of the antibiotics and crude plant extracts were measured against the isolates. The cell surface hydrophobicity and biofilm formation potential were determined, both qualitatively and quantitatively, with and without antibiotics. Finally, the molecular characterization of the biofilm forming proteins was done by amplifying the ica operon. Results: Pseudomonas aeruginosa (KC417303-05), Staphylococcus hemolyticus (KC417306), and Staphylococcus hominis (KC417307) were isolated from the otitis media specimens. Among the crude plant extracts, Acacia arabica showed significant antibacterial characteristics (MIC up to 13 mg/ml), while these isolates exhibited sensitivity towards ciprofloxacin (MIC 0.2 mu g/mL). All of the bacterial strains had hydrophobic cellular surfaces that helped in their adherence to abiotic surfaces, leading to strong biofilm formation potential (up to 7 days). Furthermore, the icaC gene encoding polysaccharide intercellular adhesion protein was amplified from S. hemolyticus. Conclusions: The bacterial isolates exhibited strong biofilm formation potential, while the extracts of Acacia arabica significantly inhibited biofilm formation among the isolates and, therefore, could be executed in the development of cost-effective biofilm inhibitor medicines.