Abstract
Purpose:
To determine the susceptibility of Australian ocular isolates of S. maltophilia to antibiotics, and to various contact-lens-multipurpose solutions (MPS).
Methods:
A total of 40 strains of S. maltophilia isolated from either contact lenses or lens storage cases of contact lens wearers were tested in the study. Bacterial susceptibilities to antibiotics were determined using a disc diffusion test. The antibiotics tested included trimethoprim-sulfamethozole, tigecycline, fluoroquinolones, aminoglycosides, β-lactams, chloramphenicol, and polymyxin B. Susceptibility of test strains to seven commonly used MPS was determined by using a broth microdilution method.
Results:
The resistant rates of isolates were 93% to imipenem, 15% to aztreonam, 13% to chloramphenicol, and 8% to cefepime. None of the isolates was resistant to trimethoprim-sulfamethozole, tigecycline, ceftazidime, gatifloxacin, levofloxacin, or moxifloxacin. The susceptibility of test strains to the test MPS varied with MIC levels ranging from 3% to 100% (full strength) MPS. The test strains were less susceptible to the MPSs containing single disinfectant (PHMB) and the MPS containing PQ-1 and Aldox than to the three recently available MPS containing dual disinfectants (p < 0.05).
Conclusions:
The Australian ocular isolates of S. maltophilia remain susceptible to trimethoprim-sulfamethozole, tigecycline, and most fluoroquinolones, but are less susceptible to MPS containing single or certain dual disinfectant/s.
Keywords: 422 antibiotics/antifungals/antiparasitics •
477 contact lens