ANTIBIOFILM ACTION OF THE HYDROALCOHOLIC EXTRACT OF Plectranthus barbatus (Brazilian boldo) ON MULTIRESISTANT STRAINS OF Acinetobacter baumannii

• Grant number: 24/20423-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2025
• End date: January 31, 2026
• Field of knowledge: Biological Sciences - Microbiology - Applied Microbiology
• Principal Investigator: Luciane Dias de Oliveira
• Grantee: Gabriel da Costa Chin
• Host Institution: Instituto de Ciência e Tecnologia (ICT). Universidade Estadual Paulista (UNESP). Campus de São José dos Campos. São José dos Campos , SP, Brazil

Abstract

The bacterium Acinetobacter baumannii is an opportunistic pathogen highly resistant to antibiotics, dehydration and common disinfectants. This resistance, especially due to its ability to form biofilms, allows A. baumannii to survive for up to a month on various surfaces, including medical equipment and hospital furniture, which facilitates its spread in hospitals, especially in Intensive Care Units (ICU). Due to the growing international concern about superbugs, concomitantly with the encouragement of the World Health Organization (WHO) for the research of new treatments, the medicinal properties of plants have gained prominence as a promising alternative in the fight against multiresistant bacteria, through the use of phytotherapeutics. In the present study, the antibacterial and antibiofilm action of the hydroalcoholic extract of the leaves of Brazilian boldo (Plectranthus barbatus) will be evaluated against multiresistant clinical strains and a standard strain of A. baumannii (ATCC 19606). In addition, the antioxidant activity analysis, quantification of the flavonoid and phenol content and High Performance Liquid Chromatography (HPLC) will be performed to identify the extract components. For this, the boldo extract will be prepared and its soluble solids content will be quantified later. In the analysis by High Performance Liquid Chromatography, an analytical method employed in the HPLC equipment will be employed, and the determination of the antioxidant action by the 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical reduction assay. The determination of the Minimum Inhibitory Concentration (MIC) and the Minimum Bactericidal Concentration (MBC) will be according to the broth microdilution assay recommended by CLSI (standard M7-A9). Subsequently, the antibiofilm action of the extract will be analyzed by the MTT test, using the minimum bactericidal concentrations (MBC) predetermined in contact with the biofilm for 5 minutes and 30 minutes in formed biofilms. The data will be analyzed using Graphpad prism 5.0 software with the ANOVA test complemented by the Tukey test with 5% significance (p<0.05).