Enhancement of the Antibiotic Activity against a Multiresistant <i>Escherichia coli</i> by <i>Mentha arvensis </i>L. and Chlorpromazine

Abstract

Background: This is the first report testing the antibiotic resistance-modifying activity of Mentha arvensis. Methods: In this study an ethanol extract of M. arvensis L. and chlorpromazine were tested for their antimicrobial activity alone or in combination with conventional antibiotics against strains of Escherichia coli. Results: The growth of two E. coli strains tested was not inhibited by the extract. The minimum inhibitory concentration and minimal bactericide concentration values were ≧1 mg/ml for both strains of E. coli used. A potentiating effect of this extract on gentamicin was demonstrated. Similarly, there was a potentiating effect of chlorpromazine on kanamycin, amikacin and tobramycin, indicating the involvement of an efflux system in the resistance to these aminoglycosides. Conclusions: It is therefore suggested that extracts from M. arvensis could be used as a source of plant-derived natural products with resistance-modifying activity, such as in the case of gentamicin, constituting a new weapon against bacterial resistance to antibiotics, as with chlorpromazine.

In vitroadditive effect ofHyptis martiusiiin the resistance to aminoglycosides of methicillin-resistantStaphylococcus aureus

“…Estragole showed synergism too with amphotericin B against Candida species (Shin & Pyun, 2004). Against bacteria, data from the checkerboard titer test confirmed synergism between norfloxacin (a quinolone) and Thymus magnus (Nakai) Nakai (Labiatae) essential oil or thymol and the extracts of Mentha arvensis L. (Labiatae) and H. martiusii were effective to enhance the antibiotic activity of aminoglycosides against Escherichia coli and Staphylococcus aureus (Shin & Kim, 2005;Coutinho et al, 2008aCoutinho et al, , 2009aCoutinho et al, , 2009c. This study demonstrates the additive effect of H. martiusii against Gram positive bacteria.…”

“…In the last few years a number of studies have been conducted in different countries to prove such efficiency (Saeed & Tariq, 2007). Many plants have been evaluated not only for direct antimicrobial activity, but also as resistance modifying agents (Coutinho et al, 2008a(Coutinho et al, , 2009a(Coutinho et al, , 2009b(Coutinho et al, , 2009c(Coutinho et al, , 2009d.…”

Modulación de la resistencia a norfloxacina de Staphylococcus aureus por Croton A. campestris y Ocimum gratissimum L.

“…Many natural products isolated from plants or animals have been evaluated not only for direct antimicrobial activity but also as resistance modifying agents (21)(22)(23)(24). Various chemical compounds, synthetic or from natural sources, have direct activity against many species of bacteria, enhancing the activity of a specific antibiotic, reversing the natural resistance of bacteria to specific antibiotics, causing the elimination of plasmids and inhibiting the active efflux of antibiotics through the plasma membrane (4). The potentiation of antibiotic activity or the reversal of antibiotic resistance allows the classification of these compounds as modifiers of antibiotic activity (1,4).…”

“…Various chemical compounds, synthetic or from natural sources, have direct activity against many species of bacteria, enhancing the activity of a specific antibiotic, reversing the natural resistance of bacteria to specific antibiotics, causing the elimination of plasmids and inhibiting the active efflux of antibiotics through the plasma membrane (4). The potentiation of antibiotic activity or the reversal of antibiotic resistance allows the classification of these compounds as modifiers of antibiotic activity (1,4). Tables 2 and 3 show the phytochemical screening and the antibacterial activity of the methanol and hexane extracts, respectively.…”

“…The interference with bacterial enzyme systems can also be a potential mechanism of action (29). These mechanisms of action can be obtained by the combination of antibiotic with extract at a subinhibitory concentration applied directly to the culture medium (1,4).…”