AUTHOR=Bezerra Filho Clovis Macêdo , da Silva Luís Cláudio Nascimento , da Silva Márcia Vanusa , Løbner-Olesen Anders , Struve Carsten , Krogfelt Karen Angeliki , Correia Maria Tereza dos Santos , Vilela Oliva Maria Luiza 

TITLE=Antimicrobial and Antivirulence Action of Eugenia brejoensis Essential Oil in vitro and in vivo Invertebrate Models

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.00424

DOI=10.3389/fmicb.2020.00424

ISSN=1664-302X

ABSTRACT=<p><italic>Eugenia brejoensis</italic> L. (Myrtaceae) is an endemic plant from caatinga ecosystem (brazilian semi-arid) which have an <italic>E. brejoensis</italic> essential oil (EbEO) with reported antimicrobial activity. In this work, <italic>in vitro and in vivo</italic> models were used to characterize the inhibitory effects of EbEO in relation to <italic>Staphylococcus aureus.</italic> EbEO inhibited the growth of all tested <italic>S. aureus</italic> strains (including multidrug resistance isolates) with values ranging from 8 to 516 μg/mL. EbEO also synergistically increased the action of ampicillim, chloramphenicol, and kanamycin. The treatment with subinhibitory concentrations (Sub-MIC) of EbEO decreased <italic>S. aureus</italic> hemolytic activity and its ability to survive in human blood. EbEO strongly reduced the levels of staphyloxanthin (STX), an effect related to increased susceptibility of <italic>S. aureus</italic> to hydrogen peroxide. The efficacy of EbEO against <italic>S. aureus</italic> was further demonstrated using <italic>Caenorhabditis elegans</italic> and <italic>Galleria mellonella</italic>. EbEO increased the lifespan of both organisms infected by <italic>S. aureus</italic>, reducing the bacterial load. In addition, EbEO reduced the severity of <italic>S. aureus</italic> infection in <italic>G. mellonella</italic>, as shown by lower levels of melanin production in those larvae. In summary, our data suggest that EbEO is a potential source of lead molecules for development of new therapeutic alternatives against <italic>S. aureus</italic>.</p>