EFICACIA ANTIMICROBIANA DE UM PEPTÍDEO CONTRA BIOFILME MISTO DE Staphylococcus aureus E Candida albicans

Abstract

ABSTRACT

Candida albicans and Staphylococcus species are, respectively, the most common fungal and bacterial agents isolated from bloodstream infections, worldwide. Moreover, it has been shown that 20% of all C. albicans bloodstream infections are polymicrobial in nature with Staphylococcus aureus being the third most common co-isolated organisms. Finding an efficient treatment strategy for polymicrobial infections is a major challenge since traditional therapies most often only target individual causative agents within specific kingdoms. Thus, the present study investigated the antimicrobial and anti-biofilm polymicrobial activity of the peptide ITR-16, a new synthetic peptide against microorganisms with a high incidence of hospital infections. The computational design was used to obtain the peptide ITR-16, the analysis of its secondary conformational structure was performed using the circular dichroism spectrum. This peptide was tested against S. aureus and C. albicans in planktonic form and mono and polymicrobial biofilm. Synergism tests were performed with other common antimicrobials. ITR-16 peptide was also tested for its preliminary acute toxicity in an in vivo model of Galleria mellonella. The ITR-16 peptide was shown to have a well-defined α-helix structure in contact with TFE and SDS. It showed antimicrobial activity, with minimal inhibitory concentrations (MICs) ranging from 0.62 to 2.5 µM. Treatment with ITR-16 at 10 x MIC significantly reduced biofilm formation and the viability of S. aureus and C. albicans biofilms. Furthermore, it demonstrated low toxicity in the G. mellonella model at anti-biofilm concentrations. These results present a new molecule with potential polymicrobial anti-biofilm activity. Keywords: peptide antimicrobial; anti-biofilm polimicrobial; computacional design.