Antibacterial and Antibiofilm Potential of Ethanolic Extracts of Duguetia vallicola (Annonaceae) against in-Hospital Isolates of Pseudomonas aeruginosa

TL;DR

This study explores the antibacterial and antibiofilm effects of plant extracts from Duguetia vallicola against Pseudomonas aeruginosa, a drug-resistant hospital pathogen.

Contribution

The novel contribution is the evaluation of Duguetia vallicola's ethanolic extracts as potential agents against Pseudomonas aeruginosa biofilms and cell membrane disruption.

Findings

Ethanolic extracts inhibited bacterial growth by over 50% at low concentrations.

Extracts inhibited mature biofilms with inhibition ranging from 48.4% to 93.7%.

Cell membrane damage was observed through material leakage and fluorescence microscopy.

Abstract

Pseudomonas aeruginosa is an opportunistic pathogen that is especially dominant in people with cystic fibrosis; the drug resistance expressed by this pathogen and its capacity for adaptation poses a significant challenge to its treatment and control, thereby increasing morbidity and mortality rates globally. In this sense, the search for new treatment alternatives is imminent today, with products of plant origin being an excellent alternative for use. The objective of this research was to evaluate the antibacterial and antibiofilm potential and to explore the possible effect of ethanolic extracts from the wood and bark of Duguetia vallicola on the cell membrane. Microdilution assays showed the inhibition of bacterial growth by more than 50%, with the lowest concentration (62.5 μg/mL) of both extracts evaluated. Furthermore, we report the ability of both extracts to inhibit mature biofilms, with inhibition percentages between 48.4% and 93.7%. Intracellular material leakage experiments (260/280 nm), extracellular pH measurements, and fluorescence microscopy with acridine orange (AO) and ethidium bromide (EB) showed cell membrane damage. This indicates that the antibacterial action of ethanolic extracts of D. vallicola is associated with damage to the integrity of the cell membrane and consequent death of these pathogens. These results serve as a reference for future studies in establishing the mechanisms of action of these extracts.

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