Revista Argentina de Microbiología (Apr 2006)
Inhibición de Paenibacillus larvae empleando una mezcla de aceites esenciales y timol Inhibition of Paenibacillus larvae employing a mixture of essential oils and thymol
Abstract
Se evaluó la actividad antimicrobiana in vitro de una mezcla de dos aceites esenciales y timol frente a Paenibacillus larvae, agente causal de la enfermedad Loque americana, que afecta a las abejas. Los aceites esenciales utilizados fueron canela (Cinnamomum zeylanicum) y tomillo (Thymus vulgaris), con el agregado de timol, componente mayoritario del tomillo presente en un 39,9%. Los parámetros medidos fueron la concentración inhibitoria mínima (CIM) en caldo Muller-Hinton, mediante dilución seriada, y la concentración bactericida mínima (CBM) en agar MYPGP. El aceite esencial de tomillo registró valores de CIM entre 150 y 250 μg/ml, y de CBM entre 200 y 300 μg/ml, mientras que para el aceite esencial de canela los valores de CIM y de CBM obtenidos fueron 50 a 100 μg/ml y 100 a 125 μg/ml, respectivamente. El timol presentó valores de CIM y de CBM similares, de 100 a 150 μg/ml. No se detectaron diferencias significativas entre las cepas bacterianas estudiadas, pero sí entre la actividad de los aceites esenciales y la del timol (PIn vitro antimicrobial activity of a mixture of two essential oils and thymol against Paenibacillus larvae, causal agent of American Foulbrood (AFB), was evaluated. The essential oils were extracted from cinnamon (Cinnamomum zeylanicum) and thyme (Thymus vulgaris). The third component used, thymol, is the major component of the essential oil of thyme which contains 39.9 % of thymol. Minimal inhibitory concentration (MIC) in Mueller-Hinton broth by the tube dilution method and minimal bactericide concentration (MBC) on MYPGP agar were evaluated. Thyme registered MIC values of 150-250 μg/ml and MBC values of 200-300 μg/ml, while the MIC and MBC values obtained for cinnamon were of 50-100 μg/ml and 100-125 μg/ml. Thymol showed similar MIC and MBC values of 100-150 μg/ml. No significant differences between the bacterial strains were detected, but significant differences between essential oils and thymol activity were registered (P<0,01). An inhibitory synergetic effect on AFB was observed reducing MIC and MBC values due to the use of a mixture of 62.5% of thyme, 12.5% of cinnamon and 25% of thymol.
