Abstract
Purpose :
To analyze the in vitro antimicrobial activity of aqueous humor after instillation of topical 0.6% besifloxacin or 0.3% gatifloxacin.
Methods :
An experimental prospective controlled study was performed using aqueous humor samples obtained from 43 patients undergoing cataract surgery. Fifteen patients were submitted to 4 topical instillation of 0.6% besifloxacin. Thirteen patients were submitted to 4 topical instillation of 0.3% gatifloxacin. A control group of 15 patients did not receive topical application of antimicrobial drug before surgery. Samples of aqueous humor were aspirated from the anterior chamber using 0.45 x 13.00 mm needle at 12 o'clock position. Samples were then stored in a sterile micro tube (Eppendorf, São Paulo, Brazil) and transported to be stored at -80°C. The microorganisms were inoculated in Tryptic Soy Broth for turbidity standards corresponding to a concentration of 0.5 of the McFarland scale (1.5 x 108 colony forming units). The microorganisms were then seeded on the respective plaques. Five strains from American Type Culture Collection (ATCC) were studied: Escherichia coli (ATCC25922), Staphylococcus aureus (ATCC25923), Staphylococcus epidermidis (ATCC12226), Klebsiella pneumoniae (ATCC13883), and Streptococcus pneumoniae (ATCC49619). Other multi-resistant microorganisms isolated from various ophthalmic diseases from our outpatient clinic were also studied: Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, Klebsiella pneumoniae, Streptococcus pneumoniae, Enterobacter sp, Acinetobacter baumannii, Streptococcus pyogenes, Streptococcus viridans, Pseudomonas aeruginosa, and Serratia sp. Aqueous humor sample from each study group were then pooled and 0.013µl of each sample were placed in a 6mm blank disc previously located in each bacteria plaque. Negative control for the blank disc was also performed. After 24 hours, the inhibition halos were measured with ruler.
Results :
Inhibition halo was not observed in aqueous humor samples submitted to 0.6% Besifloxacin. As for 0,3% gatifloxacin, inhibition halo was not observed in all microorganisms except for ATCC E. coli (8.27 ± 0.46 mm).
Conclusions :
Aqueous humor, after topical application of 0.6% besifloxacin had no bacteriostatic or bactericidal effect in any microorganisms studied. Aqueous humor after topical application of 0.3% Gatifloxacin have inhibited ATCC Escherichia coli.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.