Antibacterial and Antibiofilm Activity of the Mixed Lactobacilli Against the Most Bacterial Etiology of Otitis Media

Abstract

The present study aimed to investigate the anti-biofilm activity of Cell Free Supernatant (CFS) and Biosurfactant (BS) of mixed lactobacilli (L. acidophilus and L. plantarum) against biofilm formation by bacterial pathogens isolated from chronic otitis media. In addition, the antimicrobial potential of ciprofloxacin in combination with CFS of lactobacilli species was evaluated againt the tested pathogens. The automated identification of bacterial isolates was peroformed by VITEK2 compact system their antibiotics susceptibility was evaluated using disc diffusion method. The minimum inhibitory concentrations (MIC) of the mixed lactobacilli CFS and ciprofloxacin were determine against the bacterial isolates using broth micro-dilution assay. Anti-biofilm activities of CFS and bio-surfactant of the mixed lactobacilli were evaluated against the biofilm–associated bacterial isolates. The minimum biofilm inhibitory concentrations (MBIC50) were determined. In the current study, one hundred sixty-two ear swab were collected from had otitis media cases with chronic discharging. These patients attended to the ENT department in the medical consultation clinic at Baquba Teaching Hospital and to private doctors’ clinics. Ear swabs were taken from both genders during September 2021 to the end of December. The most bacterial species isolated from otitis media samples were Pseudomonas aeruginosa and Staphylococcus aureus. Ciprofloxacin was an effective antibiotic against the tested pathogenic bacteria. The mixed lactobacilli CFS showed an inhibitory effect at MIC90 (25%) against P. mirabilis but (50%) against P. aeruginosa, S.aureus, and K. pneumoniae. The data illustrated that CFS of mixed lactobacilli was synergized ciprofloxacin against otitis media-bacterial isolates. The CFS of mixed lactobacilli exhibited a higher MBIC50 against K. pneumoniae (50%) compared to other bacterial isolates. In addition, a higher MBIC50 of the mixed lactobacilli bio-surfactant was reported against P. aeruginosa 50%, compred to the other bacterial species. The authors concluded that tested probiotics cells, the mixed lactobacilli, and their products possessed an effective antimicrobial potential and enhanced ciprofloxacin activity to control the chronic otitis media-associated bacteria and inhibit their persistent biofilm formation.