Synergism of Plant Compound With Traditional Antimicrobials Against Streptococcus spp. Isolated From Bovine Mastitis

Abstract

Mastitis is an inflammation of the mammary gland that causes major losses in the dairy industry. Streptococcus spp. are among the main agents of this disease. Increased resistance to antibiotics is one of the causes of therapeutic failure. Plants, due to their broad chemodiversity, are an interesting source of new molecules with antibacterial activity. Using these compounds along with traditional antibiotics is a possible method for reversing resistance. The objective of this work was to determine the interactions between the activities of guttiferone-A and 7-epiclusianone, two active substances isolated from the fruits of Garcinia brasiliensis, and traditional antibiotics against Streptococcus spp. isolated from bovine mastitis and known to be resistant to them. First, the MIC for the antibiotics and bioactive compounds was determined, followed by their activities, alone and in combination. Then, their cytotoxicity was measured in bovine mammary epithelial cells. Finally, molecular docking simulations were performed to elucidate molecular details of the interactions between β-lactamase and the compounds binding to it (clavulanic acid, ampicillin, 7-epiclusianone, and guttiferone-A). The bacterial isolates were resistant to ampicillin and gentamicin. Both antibiotics showed predominantly synergistic antibacterial activities in combination with guttiferone-A or 7-epiclusianone. These two active substances were not cytotoxic at synergistic concentrations and both showed strong binding to β-lactamase, which may explain the reversal of ampicillin resistance. These substances are promising for the treatment of bovine mastitis.

Eugenol-Functionalized Magnetite Nanoparticles Modulate Virulence and Persistence in Pseudomonas aeruginosa Clinical Strains

“…In this context, nanostructured systems able to modulate microbial virulence, such as the reported magnetic NPs, in association with natural compounds that are highly biocompatible and well tolerated, could represent an efficient alternative in fighting microbial infections, especially those produced by resistant pathogens as P. aeruginosa . Moreover, such agents could be used as synergic factors for the improved antimicrobial activity of antibiotics—antimicrobial synergisms between antibiotics and plant-derived compounds have recently been reported [ 49 , 50 ]—but also between antibiotics and NPs [ 51 , 52 ].…”

Enhanced Antibacterial Activity of Meropenem against Extensively Drug-Resistant Acinetobacter baumannii by Myrtaceae Plant Extracts

“…Numerous plant-derived compounds with antibiotic-modulation activity against drug-resistant bacteria have been noted to inhibit antibacterial resistance in a variety of mechanisms [21,22]. Guttiferone-A and 7-epiclusianone, isolated from the fruits of Garcinia brasiliensis, could reverse resistance to ß-lactams by inhibiting ß-lactamase [23], while tannic acid was found to be a drug-resistant modifying agent through the inhibition of carbapenemase [24].…”

Phytochemicals: A Promising Weapon in the Arsenal against Antibiotic-Resistant Bacteria

“…This condition is an inflammation of the mammary gland that results in major economic losses to the dairy industry [ 46 ]. To combat this problem, Maia and co-workers [ 47 ] isolated guttiferone-A and 7-epiclusianone from the fruits of Garcinia brasiliensis , a tree native to the Amazon and widely cultivated in Brazil. The pharmacological properties of these two bioactive compounds, particularly their antimicrobial properties against S. aureus and Bacillus cereus [ 48 ], suggested their possible prevention of metastasis.…”