Abstract
Purpose :
The purpose of this study was to analyse the sensitivity of contact lens (CL)-related keratitis isolates of Pseudomonas aeruginosa from Australia to antibiotics, multipurpose contact lens disinfecting solutions (MPDS) and disinfectants
Methods :
The susceptibilities (minimum inhibitory and minimum bactericidal concentrations) of 17 CL-related isolates of P. aeruginosa were evaluated. Antibiotics included ciprofloxacin, levofloxacin, gentamicin, tobramycin, piperacillin, imipenem, ceftazidime and polymyxin B. The multipurpose disinfecting solutions (MPDS) OPTI-FREE PureMoist, RevitaLens OcuTec and Biotrue, and the disinfectants alexidine dihydrochloride, polyquaternium-1 , polyhexamethylene biguanide (PHMB) and myristamidopropyl dimethylamine (Aldox) were analysed for their activity. The combined susceptibility of disinfectants based on the MPDSs formulation was assessed through fractional inhibitory concentration.
Results :
All isolates were sensitive to levofloxacin and gentamicin, 2/17 were resistant to ciprofloxacin, 1/17 was resistant to tobramycin, piperacillin and polymyxin, 3/17 were resistant to ceftazidime while 12/17 were resistant to imipenem. Of all the three MPDSs, for OPTI-FREE PureMoist 16/17 strains have an MIC ≤ 12.5% for RevitaLens 9/17 strains have an MIC ≤ 12.5 and for Biotrue 5/17 strains have MIC=12.5. All the strains were killed by 100% MPDS. At the concentrations used in the MPDSs, the individual disinfectants were not active. The combinations of disinfectants tested showed no interaction other than antagonism for two strains by polyquaternium-1 and PHMB and for one strain by polyquaternium and alexidine dihydrochloride.
Conclusions :
Australian CL-related isolates of Ps. aeruginosa were sensitive to most antibiotics. There was variability in sensitivity to different MPDS. Individual disinfectant excipients had limited activity. The combination of the disinfectants showed no synergy.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.