Potencial antimicrobiano do óleo essencial de lippia sidoides contra bactérias gram-negativas multidroga resistentes

Abstract

The production of specific enzymes is one of the main ways that bacteria survive and adapt to antibiotics. Essential oils, originating from aromatic plants, are composed of chemical substances which are attributed beneficial effects for those who use them. Lippia sidoides Cham. (Verbenaceae) has its origins in the semiarid region of northeastern Brazil and the extract obtained from its leaves has anti-inflammatory, insecticidal, antibacterial, larvicidal effects, among others. Thus, the aim of this study was to evaluate the antimicrobial potential of essential oil (EO) from L. sidoides against Gram-negative bacteria isolated from healthcare-related infections (HRI) with multidrug resistance phenotype and to correlate the results obtained with the genetic profile of these microorganisms. Said oil was extracted from the leaves of this plant by steam dragging and condensation with Clevenger equipment, the chemical components of the mixture were identified and quantified by gas chromatography coupled with mass spectrometry and gas chromatography coupled with the flame ionization detector, respectively. The antibacterial potential was evaluated by Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (CBM) values against ATCC standard strains and sixty multidrug resistant (MDR) nosocomial isolates of Escherichia coli (n=20), Klebsiella pneumoniae (n=20) and Pseudomonas aeruginosa (n=20) collected from hospitals located in Sobral/ CE and belonging to the biological collection of the Laboratory of Microbiology and Parasitology (FAMED – UFC/Sobral). The results showed that thymol is the prevalent component of this EO, and at a concentration of 312μg/mL the oil was effective in inhibiting 52% of E. coli strains and about 38% of K. pneumoniae. However, for P. aeruginosa a concentration of 2.500μg/mL was needed to obtain growth inhibition of approximately 38% of the specimens. All clinical isolates analyzed are producers of extendedspectrum β-lactamases (ESBL) and among the resistance genes detected, the highest prevalence was blaCTX-M1/2, so the multi-resistance phenotype did not prevent the antibacterial action of the EO. Therefore, the substance presents itself as an efficient antibacterial compound with potential for use in fighting MDR bacterial infections.