Hydrocortisone Impairs the Activity of Antimicrobial Drugs against Clinical Isolates of Staphylococcus aureus

The clinical use of antimicrobials has increased the chances of cure and life expectancy. However, indiscriminate use and/or incorrect prescription have aggravated the worrying scenario of bacterial resistance. In antimicrobial therapies, the combined use of corticosteroids aims to modulate the inflammatory process triggered by the infection and prevent adverse reactions from antimicrobials such as nephrotoxicity. Several combinations are available as topical formulations, and they are commonly prescribed in the same device for intravenous administration in hospitals. Notwithstanding eventual benefits, the safety of these combinations remains poorly investigated. The aim of the present study was to conduct in vitro tests to assess the interference of hydrocortisone on the antimicrobial activity of some drugs against clinical isolates of Staphylococcus aureus and to provide insights into the chemical nature of such interactions. Tests of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were performed with and without the addition of hydrocortisone (HYDRO). Chemoinformatics data on predicted NMR, GC-MS and FTIR spectra of the drugs to obtain chemical data that could support a more detailed analysis of potential interaction. HYDRO elevated MIC and MBC of oxacillin, and abrogated the activity of gentamicin and chloramphenicol, suggesting that these combinations may pose a risk to clinical treatments. More studies should be carried out in animal models to confirm these effects in vivo.