In vitro antimicrobial analysis of bacterial liquid broth submitted to ozone transfer via bubble diffusion

Abstract

Purpose : Ozone is known to be a strong antimicrobial agent against bacteria by damaging its cytoplasmic membrane and inducing modification of intracellular contents. The purpose of this study is to analyze the in vitro antimicrobial activity of ozone in bacterial liquid broth.

Methods : Five bacteria related to ophthalmic infection were selected: Staphylococcus epidermidis, Staphylococcus aureus, Pseudomonas aeruginosas, Corynebacterium sp, and Streptococcus pneumoniae. Each bacterium was inoculated in respective broth until a scale of 0.5 McFarland (1.5 x 10⁸ CFU/ml) was obtained. Ozone transfer via bubble diffusion technique was performed using an ozone generator (OzoneLab OL80 Desktop Line 90° panel series, Canada) and a 2µm aerator. The concentration of the appliance was determined by a table provided by the manufacturer (Figure 1). Each bacterium was tested for two different concentrations: 8 μg/ml (group 1) and 10 μg/ml (group 2). All samples were submitted to 4 minutes of bubbling in both concentrations. Then, 5 ml of each solution was transferred to a closed chamber containing 30ml of enriched broth (Sistema Hemobac Trifasico Pediatrico, Probac, Sao Paulo, Brazil). The vials were incubated at 36°C for 5 days, and readings were performed every 24 hours. Positive control was performed using samples that were not submitted to ozone transfer.

Results : For the ozone concentration of 10 μg/ml, no bacterial growth was observed, except for Streptococcus pneumoniae. For ozone concentration of 8 μg/ml, bacterial growth was observed in all microorganism studied. The obtained data is shown in figure 2.

Conclusions : Ozone transfer via bubble diffusion in a concentration of 10 μg/ml has important antimicrobial activity against liquid broth of studied bacteria, except for Streptococcus pneumoniae. No antibacterial activity of ozone transfer was observed in any microorganism in concentration of 8 μg/ml.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.