Modulative and adaptive effect of (+)-alpha-pinene in front of commercial antimicrobials in staphylococcus aureus strains

The discovery of new molecules with antimicrobial activity and the understanding of the mechanisms of action involved are important strategies against multiresistant pathogens.Given this perspective, the positive α-pinene enantiomer appears as an alternative to combat them, as it inhibited the growth of microorganisms, including strains of Staphylococcus aureus, which gives it the possibility of its use as an isolated antimicrobial agent or in combination with other drugs.The aim of this study is to evaluate the sensitivity profile of S. aureus ATCC 25923 strain against clinical antimicrobials associated with (+) - α-pinene and how it behaves after successive exposures to subinhibitory concentrations of phytoconstituent.MIC was determined according to the Clinical Laboratory Standards Institute, the study of the modulating effect of (+)-α-pinene on the activity of antibiotics of clinical use in S. aureus strains, and the analysis of the adaptation of strain to the monoterpene tested.As a result, it was observed that for penicillin, rifampicin and nitrofurantoin there was no final change in adaptation to phytoconstituent; For vancomycin, cefoxitin, ciprofloxacin and gentamicin, the effect was considered indifferent, as no change in sensitivity was observed.Meanwhile, for the other antimicrobials the strain studied was resistant.It wasnoticed through this study that, after successive exposures to subinhibitory concentrations, the S.aureus strain suffered from bacterial stress and acquired resistance, consequently presenting a reduction in the efficacy of antimicrobials, which can be noticed by the increase of MIC against the phytoconstituent, as well as phenotypic changes visualized in cultures subjected to incubation.