title: Dexamethasone abrogates the antimicrobial and antibiofilm activities of different drugs against clinical isolates ofStaphylococcus aureusandPseudomonas aeruginosa.
abstract: Staphylococcus aureusandPseudomonas aeruginosaare part of the human microbiota and are also important bacterial pathogens, for which therapeutic options are lacking nowadays. The combined administration of corticosteroids and antimicrobials is commonly used in the treatment of infectious diseases to control inflammatory processes and to minimize potential toxicity of antimicrobials, avoiding sequelae. Although different pharmaceutical dosage forms of antimicrobials combined to corticosteroids are available, studies on the interference of corticosteroids on the pharmacological activity of antimicrobials are scarce and controversial. Here, we provide evidence of the interference of dexamethasone on the pharmacological activity of clinically important antimicrobial drugs against biofilms and planktonic cells ofS. aureusandP. aeruginosa. Broth microdilution assays of minimal inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and minimum biofilm eradication concentration (MBEC) of gentamicin, chloramphenicol, oxacillin, ceftriaxone and meropenem were conducted with and without the addition of dexamethasone. The effect of all drugs was abrogated by dexamethasone in their MIC, MBC, and MBEC, except gentamicin and meropenem, for which the MBC was not affected in some strains. The present study opens doors for more investigations onin vitroandin vivoeffects and safety of the combination of antimicrobials and glucocorticoids.
authors.affiliation: Health Sciences Faculty, University Vale do Rio Doce, Governador Valadares, 35020 220 MG, Brazil; Biological Sciences Institute, Federal University of Juiz de Fora, Juiz de Fora 35036 330, MG, Brazil.
authors.forename: Aquila
authors.initials: A
authors.lastname: Rodrigues
authors.affiliation: Health Sciences Faculty, University Vale do Rio Doce, Governador Valadares, 35020 220 MG, Brazil; Oncology Specialized Nucleus, Governador Valadares, 35044 418 MG, Brazil; Integrated Pharmacology and Drug Interactions Research Group (GPqFAR), Brazil.
authors.forename: André
authors.initials: A
authors.lastname: Gomes
authors.affiliation: Health Sciences Faculty, University Vale do Rio Doce, Governador Valadares, 35020 220 MG, Brazil; Biological Sciences Institute, Federal University of Juiz de Fora, Juiz de Fora 35036 330, MG, Brazil; Biological Sciences Institute, Federal University of Minas Gerais, Belo Horizonte 31270 901, MG, Brazil.
authors.forename: Pedro Henrique Ferreira
authors.initials: PH
authors.lastname: Marçal
authors.affiliation: Integrated Pharmacology and Drug Interactions Research Group (GPqFAR), Brazil; Biological Sciences Institute, Federal University of Minas Gerais, Belo Horizonte 31270 901, MG, Brazil.
authors.forename: Marcus Vinícius
authors.initials: MV
authors.lastname: Dias-Souza
keywords: Antimicrobials; Dexamethasone; Interference; P. aeruginosa; S. aureus