Avaliação das atividades antibacteriana e antiaderente dos óleos essenciais de Eucalyptus globulus e Eucalyptus citriodora contra cepas de Pseudomonas aeruginosa.

Abstract

Biofilm can be defined as a complex sessile microbiological ecosystem formed by one or more species of bacteria, fungi or protozoa, isolated or in combination, embedded in a matrix of extracellular polymeric substances. Among the microorganisms capable of forming biofilm is Pseudomonas aeruginosa, a gram-negative bacterium with extensive virulence factors and high resistance to antimicrobials, making it difficult to treat infections caused by it, and it is one of the main causes of nosocomial infections. In this sense, in view of various studies demonstrating their efficacy, phytotherapy and essential oils are promising therapeutic alternatives to multi-resistant microorganisms. In view of this, the aim of this study was to evaluate the antibacterial and anti-adherent activities of the essential oils of Eucalyptus globulus and Eucalyptus citriodora against clinical strains of P. aeruginosa, and to compare their antibiofilm effects with 0.12% chlorhexidine digluconate. Duplicate experiments were used to determine the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of the oils using the broth microdilution technique in 96-well plates. At the same time, the Minimum Adherence Inhibitory Concentration (MIC) was determined using the inclined glass tube technique in the presence of 5% sucrose, using proportions corresponding to the pure essential oil up to a dilution of 1:1024, and its positive control was 0.12% chlorhexidine digluconate. The results obtained indicated that the essential oils of E. globulus and E. citriodora varied between strong and moderate effects on the P. aeruginosa strains tested, as well as between bactericidal and bacteriostatic action. In addition, the oils showed an effective anti-adherent effect and were superior to the positive control, with E. globulus standing out as the most effective.