Antibacterial and Antibiofilm Activity of Selected Medicinal Plant Leaf Extracts Against Pathogens Implicated in Poultry Diseases

Abstract

Antimicrobial resistant poultry pathogens are responsible for treatment failure and economic losses, and can also be a source of resistant zoonotic infections representing a risk to human health. In 2006 the European Union banned the use of antibiotics as growth promoters in farm animals and other regions are likely to follow suit. Alternative products and strategies are sought to help maintain animal gut health to reduce the prevalence of pathogens in the food chain. The minimum inhibitory concentration (MIC) of organic and aqueous leaf extracts of Alchornea laxiflora, Ficus exasperata, Morinda lucida, Jatropha gossypiifolia, Ocimum gratissimum, and Acalypha wilkesiana were tested against bacterial poultry pathogens including Staphylococcus aureus, Enterococcus faecalis, Salmonella spp., Escherichia coli, Campylobacter spp., and fungal species (Aspergillus fumigatus, Aspergillus flavus, and Candida albicans) using a 2-fold serial microdilution method. Activity of extracts against biofilms of the pathogens was done using a modified crystal violet staining in vitro assay. The safety of extracts was determined against Vero and Caco-2 cells using a tetrazolium-based in vitro assay. Acetone and cold water extracts of M. lucida had the best activity against three bacteria (MIC = 0.05–0.07 mg/ml) and two fungal (MIC = 0.03–0.15 mg/ml) organisms, respectively. The E. coli isolate and A. flavus were the most susceptible bacteria and fungi, respectively. Caco-2 cells generally displayed higher selectivity index (SI) values compared to Vero cells and average SI values against Vero and Caco-2 cells for both bacteria and fungi ranged from 0.01 to 4.48 and 0.005 to 16.41, respectively. All plant extracts had good anti-biofilm activity (>50%) against at least one organism. The disruption of established biofilm growth by the plant samples proved to be more difficult to achieve than efficacy against planktonic forms of bacteria. This study shows that some of the plant species are potential candidates as alternative feed additives in poultry production. In the future, a poultry feed trial to evaluate their in vivo efficacy as herbal feed additives will be conducted.

Natural Strategies as Potential Weapons against Bacterial Biofilms

“…Olawuwo et al investigated the in vitro antibiofilm activity of Acalypha wilkesiana , Alchornea laxiflora , Ficus exasperata , Jatropha gossypiifolia , Morinda lucida , and Ocimum gratissimum plant extracts against poultry pathogens ( Aspergillus flavus , A. fumigatus , C. albicans , Campylobacter spp., Salmonella spp., E. coli , S. aureus, and Enterococcus faecalis ). All plant extracts showed effective biofilm inhibition of approximately >50% against the tested micro-organisms [ 160 ]. Fathi et al determined the antibiofilm potential of Malva sylvestris methanolic extract against some human pathogens, such as E. coli , S. aureus , P. aeruginosa , E. faecalis , and K. pneumoniae .…”

Antioxidant, Antibacterial and Antiqourum Sensing Properties of Selected Wild Tea Leaves of Mountain Province

“…Numerous secondary metabolites from medicinal plants have anti-QS effects have been isolated such as cinnamaldehyde, flavanones, and flavonoids have been studied and demonstrated promising anti-QS activities specifically, inhibition of HAIand AI-2-medicated bioluminescence, restrict with QS detection and influence. 34 Olawuwo et al 35 observed a comparable observation in their determination of antibiofilm formation activity of the medicinal leaf extracts against bacterial biofilms.…”

Effects of Astragalus, Epimedium, and Fructus Ligustri Lucidi extractive on antioxidant capacity, production performance, and immune mechanism of breeding pigeons under stress

“…It is now a crucial method for reducing the negative effects of stress on animals both domestically and overseas ( Liu and Yang, 2006 ). For the past several years, plant extracts has been increasingly used in poultry and mammals ( Olawuwo et al, 2022 ).…”