<p>Evaluation of essential oil obtained from <em>Mentha×piperita</em> L. against multidrug-resistant strains</p>

Abstract

BackgroundBacterial multidrug resistance currently poses an increasingly serious threat, with important clinical consequences regarding treatment options. In 2017, the WHO released a global list of resistant bacteria, identifying multidrug-resistant (MDR) Gram-negative bacteria such as carbapenem-resistant Enterobacteriaceae, Pseudomonas aeruginosa or Acinetobacter baumannii, extended-spectrum cephalosporin-resistant Enterobacteriaceae as critical priorities for developing new strategies of treatment.PurposeThe novelty presented in this study refers to the evaluation of the volatile oil obtained from the leaves of Mentha×piperita L., on MDR strains from hospitalized patients.Material and methodsThe essential oil was extracted by steam distillation and tested on six reference bacterial strains and also on the MDR strains collected from patients of the “Pius Brînzeu” Emergency Clinical County Hospital Timișoara. The in vitro antibacterial activity was evaluated by agar disk diffusion method and microdilution method.ResultsTesting the antibacterial activity of peppermint oil on both reference strains and isolated MDR strains from hospitalized patients demonstrated its bactericidal effect. Minimum inhibitory concentration (MIC) was lower (20 mg/mL) for Staphylococcus aureus, Escherichia coli and Proteus mirabilis and higher (40 mg/mL) for Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii strains. Minimum bactericidal concentration (MBC) was equal to MIC, with the exception of Pseudomonas aeruginosa strains, where MBC was the double of MIC.ConclusionThe present study highlights the bactericidal activity of Mentha×piperita L. essential oil on all tested MDR or extensively drug-resistant Gram-positive and Gram-negative strains of Staphylococcus aureus, Escherichia coli, Klebsiellapneumoniae, Proteus mirabilis, Pseudomonas aeruginosa and Acinetobacter baumannii. This oil may be a therapeutic option in the near future for many infectious diseases produced by MDR bacteria.

Properties of Salvia officinalis L. and Thymus serpyllum L. Extracts Free and Embedded into Mesopores of Silica and Titania Nanomaterials

“…The antibacterial and antifungal activity of these compounds were evaluated by the agar disk diffusion method and dilution method, according to the Clinical Laboratory and Standard Institute (CLSI) [ 32 , 33 ].…”

Biological Evaluation of Black Chokeberry Extract Free and Embedded in Two Mesoporous Silica-Type Matrices

“…The antimicrobial activity of the samples was evaluated by both the agar disk diffusion method and the dilution method, according to the procedures outlined by the Clinical Laboratory and Standard Institute (CLSI), the European Committee on Antimicrobial Susceptibility Testing (EUCAST), and the other studies [26][27][28][29][30].…”

Phytochemical and Biological Screening of Oenothera biennis L. Hydroalcoholic Extract

“…The disk diffusion method was performed according to the CLSI (Clinical Laboratory and Standards Institute Inc.) guidelines [ 36 , 37 , 38 , 39 ]. Ten microliters of the OB extract were deposited onto a blank paper disk (BioMaxima, Lublin, Poland) and was then placed on the surface of Mueller-Hinton agar plates (Sanimed, Bucharest, Romania), inoculated with 100 µL of a microbial suspension (0, 5 McFarland) in saline solution.…”

“…The OB extract was tested by the broth dilution method in accordance with the CLSI and European Committee on Antimicrobial Susceptibility Testing (EUCAST) [ 36 , 37 , 38 , 39 ]. A concentration of 200 μg/mL in Mueller Hinton broth (Sanimed, Bucharest, Romania) of the OB extract was initially prepared.…”