ABSTRACT
The objective of this study was to evaluate the antimicrobial potential of Lippia alba essential oil (EOLa) and to investigate the effect of food ingredients on its efficacy. The antimicrobial potential of the oil was determined by the presence or absence of inhibition zones, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against Escherichia coli, Listeria innocua, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella choleraesuis and Staphylococcus aureus. The effect of food ingredients and the pH on the antimicrobial efficacy of oil was assessed by monitoring the maximum growth rate of Listeria monocytogenes in model media. The model media included potato starch (0, 1, 5 or 10%), beef extract (1, 5, 3, 6 or 12%), sunflower oil (0, 5 or 10%) and TSB broth at pH levels of 4, 5, 6 or 7. The EOLa showed efficacy at all concentrations (50%, 25%, 6.25%, 3%, 1.5%, 0.8%, 0.4% and 0.2%) evaluated, against all bacterial species, Gram-positive and Gram-negative. The antimicrobial efficacy of EO was found to be a function of ingredient manipulation. Proteins and lipids had a negative impact on the oil effectiveness, indicating the protective action of both on the microbial specie tested. On the contrary, at the highest concentration of starch (10%), the lower rate growth of L. monocytogenes was detected, therefore indicating a positive effect of carbohydrates on the oil effectivenes. Regarding the pH, the studies showed that the rate of microbial growth increased with increasing pH. It was concluded that the use of EOLa is more effective control pathogenic and spoilage bacteria when applied to starchy foods under an acidic pH.
Subject(s)
Anti-Bacterial Agents/pharmacology , Drug Interactions , Food Analysis , Gram-Negative Bacteria/drug effects , Gram-Positive Bacteria/drug effects , Lippia/chemistry , Oils, Volatile/pharmacology , Anti-Bacterial Agents/isolation & purification , Culture Media/chemistry , Hydrogen-Ion Concentration , Listeria monocytogenes/growth & development , Microbial Sensitivity Tests , Oils, Volatile/isolation & purificationABSTRACT
Um grupo de 80 gestantes atendidas no CESA-AM, não apresentando quais-quer sintomas ou sinais de infecção urinária, foi selecionado através de entre-vista para investigação da incidência de Bacteriúria Assintomática (BA). O diagnóstico de BA foi realizado através de urocultura, a sensibilidade dos agen-tes etiológicos isolados foi avaliada por antibiograma e a incidência de BA foi correlacionada com idade, parição e trimestre de gestação. Nove (11,25 por cento) gestantes apresentaram BA e a maior incidência ocorreu na faixa etária de 15 a 25 anos, na primeira gestação e após o primeiro trimestre de gestação. A enterobactéria Escherichia coli foio principal agente etiológico isolado (77,78 por cento).