Treatment of tympanic membrane fibroblasts with 0.3% ciprofloxacin, as found in eardrops, reduces fibroblast viability and collagen and α-tubulin protein levels. These findings could explain tympanic membrane healing problems associated with quinolone eardrops.

Objective To assess collagen and α-tubulin levels of mouse tympanic membrane fibroblasts treated with quinolone and aminoglycoside antibiotics at concentrations found in eardrops. Study Design Prospective controlled cell culture study. Setting Academic tertiary medical center. Subjects Mouse tympanic membrane fibroblasts. Methods In experiment 1, fibroblasts were treated with the following for 24 or 48 hours: phosphate-buffered saline (negative control), dilute hydrochloric acid (positive control), 0.5% gatifloxacin, or commercially available 0.3% ciprofloxacin, 0.3% ciprofloxacin + 0.1% dexamethasone, 0.3% ofloxacin, 0.5% moxifloxacin, 0.3% gentamicin, or 3.5 mg/mL of neomycin + polymyxin B sulfate + hydrocortisone. In experiment 2, cells were treated with the pure form of gatifloxacin, gentamicin, ofloxacin, or ciprofloxacin. Cells were observed with phase-contrast microscope until harvested. Proteins were extracted for Western blotting with antibodies against collagen α1 type I (collagen 1A1) and α-tubulin, and for densitometry to quantify levels. Results Collagen and tubulin levels in fibroblasts treated with ofloxacin, moxifloxacin, gatifloxacin, or gentamicin for 24 hours were not different from the saline control. Fibroblasts treated with neomycin + polymyxin B + hydrocortisone, ciprofloxacin + dexamethasone, or ciprofloxacin for 24 hours had lower collagen 1A1 and α-tubulin levels (all P < .001) than the negative control. After 48 hours, fibroblasts treated with neomycin + polymyxin B sulfate + hydrocortisone, ciprofloxacin + dexamethasone, ciprofloxacin, or moxifloxacin had lower collagen 1A1 ( P ≤ .007) and α-tubulin ( P < .0001; except ciprofloxacin, P = .033) as compared with control. In experiment 2, only cells treated with ciprofloxacin had lower collagen 1A1 and α-tubulin levels and cell viability (all P < .0001) than control. Cytotoxicity assay and phase-contrast images mirrored the protein findings. Conclusion The adverse impact of topical antibiotic exposure on tympanic membrane collagen and tubulin protein levels is drug specific. This may be important for selection of ototopical therapy.

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ObjectiveTo determine if widely available solutions can effectively kill ticks that may be found in the human ear canal.MethodsThis study was prospective, controlled and blinded animal study. Lone star ticks (Amblyomma americanum), both nymphal and adult, were submerged in one of four preparations (acetone, isopropyl alcohol 70%, ethanol 95%, or 4% lidocaine) in test tubes (n = 20 per group) for 20 minutes. Ticks were agitated by intermittent probing. Activity of the nymphal ticks was directly observed while those of the adult ticks was video‐recorded during the exposure period. Two blinded investigators viewed the videos of adult ticks and during the exposure period to determine the time until death (ie, movement cessation). Mortality was assessed immediately after exposure, and confirmed 24 and 48 hours after exposure.ResultsAcetone killed ticks most rapidly (nymph mean time = 185.1 s; adult mean time = 562.9 s). Isopropyl alcohol 70% (nymphs, 328.9 s; adults, 1128.4 s) and ethanol 95% (nymphs, 294 s; adults, 1129.4 s) took longer to kill the ticks. All ticks treated with 4% lidocaine survived. These differences were significant (nymphs, P < .0001; adults, P < .0001).ConclusionsAcetone was the fastest acting and most effective reagent, followed by ethanol and isopropyl alcohol. These solutions may prove useful in otoacariasis with an intact tympanic membrane.Level of EvidenceN/A

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