Maxitrol as an antibiofilm agent with potential applications in Otolaryngology-Head and Neck Surgery

Objectives

Maxitrol (Novartis) is a topical ophthalmic medication that contains polymyxin B, neomycin, and dexamethasone. If it possesses antibiofilm activity, it may be useful for treating diseases of the head and neck in which biofilms are implicated, including chronic rhinosinusitis, chronic suppurative otitis media and osteoradionecrosis. We investigated the in vitro efficacy of Maxitrol against Staphylococcus aureus and Pseudomonas aeruginosa biofilms.

Methods

Minimum biofilm eradication concentration (MBEC) assays were performed using biofilms of P. aeruginosa ATCC 27853 and S. aureus ATCC 6538 type strains, grown on 96-pin lids and treated in Maxitrol for 30 min, 1 h, or 6 h. Isolates of both species were collected from the middle meatuses of patients with cystic fibrosis. Biofilms of clinical isolates were grown and treated in vitro for 6 h with Maxitrol, both undiluted at full concentration and at the identified MBEC, then cultured to identify bacterial survival.

Results

Neither type strain was eradicated at 30 min nor S. aureus at 1 h at any tested concentration. P. aeruginosa was eradicated by a median of 90% and 5.6% Maxitrol at 1 and 6 h, respectively, and S. aureus with 90% Maxitrol at 6 h. Undiluted Maxitrol reliably eradicated all clinical isolates of P. aeruginosa but only one of five S. aureus isolates.

Conclusions

Maxitrol reliably eradicates P. aeruginosa biofilm but not S. aureus biofilm in vitro. It may have a therapeutic role against biofilms in which P. aeruginosa is the dominant pathogen.

Level of Evidence

N/A.