AUTHOR=Kim Yong-Guy , Lee Jin-Hyung , Raorane Chaitany J. , Oh Seong T. , Park Jae G. , Lee Jintae 

TITLE=Herring Oil and Omega Fatty Acids Inhibit Staphylococcus aureus Biofilm Formation and Virulence

JOURNAL=Frontiers in Microbiology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2018.01241

DOI=10.3389/fmicb.2018.01241

ISSN=1664-302X

ABSTRACT=<p><italic>Staphylococcus aureus</italic> is notorious for its ability to become resistant to antibiotics and biofilms play a critical role in antibiotic tolerance. <italic>S. aureus</italic> is also capable of secreting several exotoxins associated with the pathogenesis of sepsis and pneumonia. Thus, the objectives of the study were to examine <italic>S. aureus</italic> biofilm formation <italic>in vitro</italic>, and the effects of herring oil and its main components, omega fatty acids [<italic>cis</italic>-4,7,10,13,16,19-docosahexaenoic acid (DHA) and <italic>cis</italic>-5,8,11,14,17-eicosapentaenoic acid (EPA)], on virulence factor production and transcriptional changes in <italic>S. aureus</italic>. Herring oil decreased biofilm formation by two <italic>S. aureus</italic> strains. GC-MS analysis revealed the presence of several polyunsaturated fatty acids in herring oil, and of these, two omega-3 fatty acids, DHA and EPA, significantly inhibited <italic>S. aureus</italic> biofilm formation. In addition, herring oil, DHA, and EPA at 20 μg/ml significantly decreased the hemolytic effect of <italic>S. aureus</italic> on human red blood cells, and when pre-treated to <italic>S. aureus</italic>, the bacterium was more easily killed by human whole blood. Transcriptional analysis showed that herring oil, DHA, and EPA repressed the expression of the α-hemolysin <italic>hla</italic> gene. Furthermore, in a <italic>Caenorhabditis elegans</italic> nematode model, all three prolonged nematode survival in the presence of <italic>S. aureus</italic>. These findings suggest that herring oil, DHA, and EPA are potentially useful for controlling persistent <italic>S. aureus</italic> infection.</p>