Antibacterial effect of sevoflurane and isoflurane

Multidrug resistant bacteria are increasing worldwide and therapeutic options are limited. Some anaesthetics have shown antibacterial activity before. In this study, we have investigated the antibacterial effect of the halogenated anaesthetic agents sevoflurane and isoflurane against a range of resistant pathogens.

Two experiments were conducted. In the first, bacterial suspensions of both ATCC and resistant strains of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa were exposed to liquid sevoflurane and isoflurane during 15, 30 and 60 minutes. In the second experiment clinical resistant strains of E. coli, Klebsiella pneumoniae, Enterobacter cloacae, P. aeruginosa, Acinetobacter baumannii, S. aureus, and Enterococcus faecium were studied. Previously inoculated agar plates were irrigated with the halogenated anaesthetic agents and these were left to evaporate before the plates were incubated. In both experiments colony forming units were counted in resultant plates.

In the first experiment, isoflurane showed faster and higher antimicrobial effect than sevoflurane against all the strains studied. Gram-negative organisms were more susceptible. In the second experiment, E. faecium was found to be resistant to both halogenated agents; only isoflurane showed statistically significant activity against the rest of the strains studied.

Both halogenated agents, but particularly isoflurane, showed in vitro antibacterial activity against pathogens resistant to conventional antibiotics. Further investigation is required to determine whether or not they also exhibit this property in vivo. This might then allow these agents to be considered as rescue treatment against multidrug resistant pathogens, including a topical use in infected wounds.