Abstract
Purpose: :
Bacterial biofilm formation has been implicated in the pathogenesis of endophthalmitis. Biofilm formation may result in a prolonged treatment course or poor initial response to treatment due to difficulty in obtaining complete clearance of infection as a result of increased resistance to host defenses or antibiotics. The hypothesis to be tested by this study is that biofilm proficient bacterial strains will cause chronic endophthalmitis or late presentation of acute endophthalmitis, whereas biofilm deficient strains will present sooner due to provocation of a more brisk inflammatory response. Biofilm formation data from clinical endophthalmitis isolates are described in the current study.
Methods: :
Clinical endophthalmitis isolates were grown in brain-heart infusion broth (BHIB), diluted to optical density (OD) 600 of 0.01 in BHIB with 0.2% glucose, plated in a 96 well microtiter plate, incubated for 20 hours at 37 degrees Celsius in a closed, humidified container, and post-incubation OD 600 recorded as a metric of growth. Nonadherent cells were removed and adherent cells were stained with 0.1% crystal violet (CV). CV was solubilized using 30% glacial acetic acid for 15 minutes. Relative biofilm formation was assayed by reading A 590 nm using a microplate reader and correcting for post-incubation OD 600.
Results: :
Data are available for 39 endophthalmitis isolates. Biofilm formation ranged from 0.002458 to 7.708956. The average formation was 0.748123, with a standard deviation of 1.462574. Approximately 65 additional isolates are being studied.
Conclusions: :
Clinical endophthalmitis isolates demonstrate widely variable biofilm formation. These data will be used to assess correlation of biofilm formation with clinical course and outcomes of endophthalmitis.
Keywords: endophthalmitis • bacterial disease