OBJECTIVES: Aminoglycoside ototoxicity may be mitigated by administration of dexamethasone; however, dexamethasone could theoretically impair its antibacterial properties. The purpose of this experiment was to determine if dexamethasone decreases the antibacterial activity of gentamicin against Pseudomonas aeruginosa (PA) and Stapholococcus aureus (SA).
STUDY DESIGN: In vitro microbiological assay.
METHODS: Four separate trials of minimum inhibitory concentration (MIC) testing were performed for gentamicin against five PA strains and six SA strains, with and without the addition of high and low concentrations of dexamethasone.
RESULTS: MICs were not changed by more than one dilution with the addition of either high or low concentrations of dexamethasone for any of the PA and SA strains.
CONCLUSION: Dexamethasone does not impair the antibacterial efficacy of gentamicin for PA and SA. This supports the role of dexamethasone as an otoprotectant with aminoglycoside therapy.
Get full access to this article
View all access options for this article.
References
1.
MascarettiO.Bacteria Versus Antibacterial agents: an integrated approach. Washington, DC: ASM Press; 2003. p. 229–333.
2.
ChambersHFThe aminoglycosides. In: HardmanJGLimbirdLEGilmanAG, editors. Goodman & Gilman's the pharmacological basis of therapeutics. New York: McGraw-Hill; 2001. p. 1219–38.
3.
HimenoCKomedaMIzumikawaM. Intra-cochlear administration of dexamethasone attenuates aminoglycoside ototoxicity in the guinea pig. Hear Res2002;167:61–70.
4.
ParkSKChoiDRussellP. Protective effect of corticosteroid against the cytotoxicity of aminoglycoside otic drops on isolated cochlear outer hair cells. Laryngoscope2004;114:768–71.
RappaportJMBhattSMBurkardRF. Prevention of hearing loss in experimental pneumococcal meningitis by administration of dexamethasone and ketorolac. J Infect Dis1999;179:264–8.
9.
HartnickCJKimHYChutePM. Preventing labyrinthitis ossificans: The role of steroids. Arch Otolaryngol Head Neck Surg2001; 127:180–3.
10.
LiZLiRChenJ. Mutational analysis of the mitochondrial 12S rRNA gene in Chinese pediatric subjects with aminoglycoside-induced and non-syndromic hearing loss. Hum Genet2005;117:9–15.
11.
GuanMXMolecular pathogenetic mechanism of maternally inherited deafness. Ann N Y Acad Sci2004;1011:259–71.
12.
NCCLS methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically; approved standard, 6th ed.Wayne, PA; National Committee for Clinical Laboratory Standards; 2003.
13.
LoewDSchusterOGraulEHDose-dependent pharmacokinetics of dexamethasone. Eur J Clin Pharmacol1986;30:225–30.
14.
TothGGKloostermanCUgesDR. Pharmacokinetics of high-dose oral and intravenous dexamethasone. Ther Drug Monit1999; 21: 532–5.
15.
MooreRDSmithCRLietmanPSRisk factors for the development of auditory toxicity in patients receiving aminoglycosides. J Infect Dis1984;149:23–30.
16.
PlotkinBJRooseRJEriksonQ. Effect of androgens and glucocorticoids on microbial growth and antimicrobial susceptibility. Curr Microbiol2003;47:514–20.
17.
CaronzoloDLuciniVPannacciM. Glucocorticoids increase in vitro and in vivo activities of antibiotics against Chlamydophila pneumoniae. Antimicrob Agents Chemother2004;48:4878–81.
18.
BodeHBMullerR.Possibility of bacterial recruitment of plant genes associated with the biosynthesis of secondary metabolites. Plant Physiol2003;132:1153–61.
19.
RolandPSKreislerLSReeseB. Topical ciprofloxacin/dexamethasone otic suspension is superior to ofloxacin otic solution in the treatment of children with acute otitis media with otorrhea through tympanostomy tubes. Pediatrics2004;113:40–6.
20.
PitcairnMSchulerJErvePR. Glucocorticoid and antibiotic effect on experimental gram-negative bacteremic shock. Arch Surg1975;110:1012–5.
21.
WeisfeltMvan de BeekDde GansJ.Dexamethasone treatment in adults with pneumococcal meningitis: Risk factors for death. Eur J Clin Microbiol Infect Dis2006;25:73–8.
22.
NeuweltEALawrenceMSBlankNKEffect of gentamicin and dexamethasone on the natural history of the rat Escherichia coli brain abscess model with histopathological correlation. Neurosurgery1984; 15:475–83.
23.
CabellosCMartinez-LacasaJTubauF. Evaluation of combined ceftriaxone and dexamethasone therapy in experimental cephalosporin-resistant pneumococcal meningitis. J Antimicrob Chemother2000; 45: 315–20.
