Alkyl Gallates, Intensifiers of β-Lactam Susceptibility in Methicillin-Resistant Staphylococcus aureus

Abstract

We found that ethyl gallate purified from a dried pod of tara (Caesalpinia spinosa) intensified ␤-lactam susceptibility in methicillin-resistant and methicillin-sensitive strains of Staphylococcus aureus (MRSA and MSSA strains, respectively). This compound and several known alkyl gallates were tested with MRSA and MSSA strains to gain new insights into their structural functions in relation to antimicrobial and ␤-lactam susceptibility-intensifying activities. The maximum activity of alkyl gallates against MRSA and MSSA strains occurred at 1-nonyl and 1-decyl gallate, with an MIC at which 90% of the isolates tested were inhibited of 15.6 g/ml. At concentrations lower than the MIC, alkyl gallates synergistically elevated the susceptibility of MRSA and MSSA strains to ␤-lactam antibiotics. Such a synergistic activity of the alkyl gallates appears to be specific for ␤-lactam antibiotics, because no significant changes were observed in the MICs of other classes of antibiotics examined in this study. The length of the alkyl chain was also associated with the modifying activity of the alkyl gallates, and the optimum length was C5 to C6. The present work clearly demonstrates that the length of the alkyl chain has a key role in the elevation of susceptibility to ␤-lactam antibiotics.

Antimicrobial activity of green tea extract against isolates of methicillin–resistant Staphylococcus aureus and multi–drug resistant Pseudomonas aeruginosa

“…Camellia sinensis (C. sinensis), which is one of the most popular beverages worldwide, has been reported to have antimicrobial activities against various pathogenic bacteria [10][11][12][13] , including MRSA [15] and MDR-P. aeruginosa [14][15][16] . However, in Indonesia, there is no study on investigation of the antibacterial effects of C. sinensis against MRSA and MDR-P. aeruginosa.…”

Antibiotic Resistance and the Prospects of Medicinal Plants in the Treatment of Salmonellosis

“…Bioassay directed fractionation of the extracts revealed that epicatechin gallate (ECG), epigallocatechin gallate (EGCG), epicatechin (EC), and caffeine (CN) are the bioactive components. ECG and CG reduced MIC values for oxacillin from 256 and 512 to 1 and 4 mgl-1 against MRSA (Shibata et al, 2005). Ethyl gallate, a conginer of alkyl gallates purified from a dried pod of tara (Caesalpinia spinosa) native to South America, intensified lactam susceptibility in MRSA an MSSA strains (Shibata et al, 2005).…”

“…ECG and CG reduced MIC values for oxacillin from 256 and 512 to 1 and 4 mgl-1 against MRSA (Shibata et al, 2005). Ethyl gallate, a conginer of alkyl gallates purified from a dried pod of tara (Caesalpinia spinosa) native to South America, intensified lactam susceptibility in MRSA an MSSA strains (Shibata et al, 2005). The abietane diterpenes, (carnosic acid carnosol) isolated from the aerial parts of Rosmarinus officinalis by fractionation of its chloroform extract at 10 μgml-1, potentiated the activity of erythromycin (16 -32 fold) against strains of S. aureus that express the two efflux proteins MsrA and TetK.…”

“…Owing to their popular use as remedies for many infectious diseases, searches for substances with antimicrobial activity in plants are frequent (Shibata et al, 2005;Betoni et al, 2006). Plants are rich in a wide variety of secondary metabolites, such as tannins, terpenoids, alkaloids, and flavonoids, which have been found in vitro to have antimicrobial properties (Cowan, 1999;Lewis and Ausubel, 2006).…”

Antimicrobial activity and bioautographic study of antistaphylococcal components from Caesalpinia pyramidalis Tull.

“…The strains of MRSA are resistant to all β-lactamics, macrolides, tetracycline, aminoglycosides, while the two glycopeptides (vancomycin and teicoplanin) remain the only alternatives for clinical treatment against infections of MRSA multiresistant S. aureus (Shibata et al, 2005). However, S. aureus with intermediate susceptibility to vancomycin (VISA) or S. aureus glycopeptides (GISA) has recently been identified in different countries.…”