STAPLETON PD, SHAH S, TAYLOR PW, NAGAOKA Y, KUMAGAI A, UESATO S; Interscience Conference on Antimicrobial Agents and Chemotherapy (43rd: 2003: Chicago, Ill.).

Abstr Intersci Conf Antimicrob Agents Chemother Intersci Conf Antimicrob Agents Chemother. 2003 Sep 14-17; 43: abstract no. F-2160.

School of Pharmacy, London, United Kingdom.

BACKGROUND: Catechins with gallate substituents, such as epicatechin gallate (ECg), isolated from green tea, have weak anti-Staphylococcus aureus (anti-Sa) activity (128 microg/ml) but have the capacity to modulate oxacillin resistance in S. aureus (ORSA). Other compounds with gallate moieties, for example, octyl gallate have moderate anti-Sa activity (16 microg/ml) but gallic acid has no activity. ORSA grown in the presence of ECg have thickened cell walls and form pseudomulticellular aggregates. The aim of this study was to determine whether the anti-Sa activity of catechins could be improved by substitution of the gallate group with 3-O-acyl chains of varying lengths (C[4] to C[18)] and to assess the affect these substitutions have on the capacity of these compounds to modulate oxacillin resistance. METHODS: The compounds were evaluated against S. aureus BB568 (a constitutive PBP2a producer), EMRSA-15 and EMRSA-16 by MIC testing in Mueller-Hinton broth (plus 2% NaCl) at 35degreesC for 24 hrs. RESULTS: 3-O-acyl-(+)-catechins with chain lengths of C[4], C[6], C[16] and C[18] had high MICs (>/= 32 microg/ml) for S. aureus BB568. Compounds with chain lengths of C[8], C[10], C[12] and C[14] had consistently lower MICs (16 microg/ml) when tested against S. aureus BB568 and EMRSA-16 but chain lengths of C[12] and C[14] were less effective against EMRSA-15 (>/= 32 microg/ml). The anti-MRSA activity of 3-O-octanoyl catechin was bactericidal. 3-O-acyl catechins tested at a 1/4 MIC did not reduce the oxacillin MIC greater at two-fold. Growth of S. aureus BB568 in the presence of 3-O-octanoyl catechin (1/4 MIC) gave rise to pseudomulticellular aggregates but no cell wall thickening was observed. CONCLUSION: Fatty acid chains, particularly with chain lengths of C[8] and C[10], enhanced the anti-Sa activity of (+)-catechin and warrant further investigation as anti-ORSA agents.

Publication Types:

• Meeting Abstracts

Keywords:

• Catechin
• Gallic Acid
• Microbial Sensitivity Tests
• Oxacillin
• Plant Extracts
• Staphylococcal Infections
• Staphylococcus aureus
• Tea
• epicatechin gallate
• octyl gallate

Other ID:

• GWAIDS0026124

UI: 102265748

From Meeting Abstracts