CLINICAL QUESTION
What is the in vitro efficacy of the ophthalmic medication Maxitrol against Staphylococcus aureus and Pseudomonas aeruginosa biofilms?
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July 2024BOTTOM LINE
Maxitrol reliably eradicates P. aeruginosa biofilm but not S. aureus biofilm in vitro.
BACKGROUND: Bacterial biofilms are a feature of many chronic diseases of the head/neck. Few of the topical antibiofilm agents that can be used to eradicate biofilms in vitro are suitable for otolaryngological application. Maxitrol may demonstrate antibiofilm activity and may therefore be useful in the management of biofilm-related disease in the head/neck.
STUDY DESIGN: In vitro study.
SETTING: Department of Surgery, University of Auckland, Auckland, New Zealand.
SYNOPSIS: Researchers performed minimum biofilm eradication concentration (MBEC) assays using biofilms of P. aeruginosa ATCC 27853 and S. aureus ATCC 6538 strains. Isolates of both species were chosen because of the high rates of biofilm formation and multi-drug resistant strains in patients. The isolates were collected from the middle meatuses of patients with cystic fibrosis. Biofilms of the isolates were grown on 96-pin lids and treated in vitro for six hours with Maxitrol, a medication containing polymyxin B (recognized to be active against bacterial biofilms), neomycin, and dexamethasone, used both in undiluted form and at the identified MBEC. The isolates were then cultured to identify bacterial survival. Results showed that P. aeruginosa biofilms were eradicated using a median of 90% and 5.6% Maxitrol at one and six hours, respectively, and S. aureus with 90% Maxitrol at six hours. Undiluted Maxitrol reliably eradicated all clinical isolates of P. aeruginosa but only one of five S. aureus isolates. Overall findings suggest that Maxitrol may be useful in managing difficult biofilm-associated otolaryngological conditions amenable to topical application of antimicrobials, particularly where P. aeruginosa is the dominant pathogen. Study limitations include the use of only one of several similar products.
CITATION: Hale SJM, Kim R, O’Carroll M, et al. Maxitrol as an antibiofilm agent with potential applications in otolaryngology-head and neck surgery. Laryngoscope Investig Otolaryngol. 2024;9:e1245.