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Background: The aim of this study was to investigate the synergistic effect of ciprofloxacin (CPFX) and fosfomycin (FOM) on CPFX-resistant Pseudomonas aeruginosa strains. Methods: The synergistic effect was evaluated using the fractional inhibitory concentration index, acute bactericidal effect and morphological observation. Results: In the fractional inhibitory concentration index experiments, the combination of CPFX with FOM showed a synergistic effect in 20 of 74 (27.0%) strains of P. aeruginosa. From the morphological observations, it was determined that CPFX affected the outer membrane structure. CPFX combined with FOM caused striking morphological changes, resulting in bacteriolysis. A time lag experiment suggested that the addition of CPFX prior to FOM produced more pronounced bactericidal activity than the addition of FOM prior to CPFX. Conclusions: These results indicate that the combination of CPFX with FOM induces a synergistic effect on CPFX-resistant P. aeruginosa strains. The role of CPFX is thought to be related to damage of the outer membrane, enhancing FOM penetration.

Traumatic luxation of the stapes into the vestibule is a rare entity, and the disease complicated with pneumolabyrinth is extremely rare. We report the case of a 72-year-old woman with pneumolabyrinth associated with a stapediovestibular dislocation. The patient presented with vertigo and nystagmus following penetrating trauma to the middle ear. High resolution computed tomography scans demonstrated air in the vestibule and dislocation of the stapes. Exploratory tympanotomy demonstrated oozing of the perilymph from the oval window and depression of the stapes into the vestibule. Pneumolabyrinth and stapes luxation detected by high resolution computed tomography should be predictive of a perilymphatic fistula.

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Burow's solution has been shown to be effective against chronic suppurative otitis media and otitis externa. We demonstrated that Burow's solution had antibacterial effects against Staphylococcus aureus and Pseudomonas aeruginosa, inducing ultrastructural changes in these bacteria in vitro. S. aureus strain 209P and P. aeruginosa strain IID1130 were treated with 13% Burow's solution. Viable cell counts were determined to measure bactericidal effects. Ultrastructural changes in cells of both strains were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Viable cell counting revealed that S. aureus cells treated with Burow's solution were killed within 30 min. The viable cell count of P. aeruginosa was reduced by 1 × 10(7) colony-forming units/ml (CFU/ml) after a 60-min treatment. SEM examination of S. aureus revealed blebbing on the surface of bacterial cells, whereas TEM revealed undulating deformation of the bacterial cell wall, diluted cytoplasm, and cell membrane detachment. SEM observations of P. aeruginosa revealed a more apparent undulating deformation of the bacterial cell surface. TEM observations also revealed deformations in the bacterial cell wall and diluted cytoplasm in both bacteria. These findings show that Burow's solution is active against S. aureus and P. aeruginosa, resulting in damage to the cell wall.