Atividade antibacteriana de óleos essenciais de plantas frente a linhagens de Staphylococcus aureus e Escherichia coli isoladas de casos clínicos humanos

Abstract

A ação antibacteriana in vitro de óleos essenciais de seis plantas foi verificada por meio da Concentração Inibitória Mínima (CIM=%v/v) pela diluição dos óleos em meio de cultura Mueller Hinton Agar, frente a linhagens de Staphylococcus aureus (n=16) e Escherichia coli (n=16) isoladas de casos clínicos humanos, além de 1 amostra padrão ATCC para cada espécie (Sa ATCC 25923 e Ec ATCC 25922), e determinação de curvas de sobrevivência em concentrações equivalentes a CIM90% dos respectivos óleos. O óleo essencial de canela foi o mais eficiente, com valores de CIM90% de 0,047 e 0,09 para S. aureus e E. coli respectivamente, enquanto gengibre (0,09), cravo da índia (0,095) e capim cidreira (0,1) apresentaram eficiências semelhantes para S. aureus. Frente a E. coli, os óleos de gengibre (0,52) e capim cidreira (0,55) foram equivalentes quanto à eficiência. De acordo com as curvas de sobrevivência, foi possível verificar também que os valores de CIM90% obtidos podem ser tanto bactericidas ou bacteriostáticas de acordo com a bactéria testada. Em conclusão, verificou-se que os óleos essenciais testados foram efetivos no controle do desenvolvimento bacteriano, sendo o potencial antimicrobiano diferente em função da espécie bacteriana testada, sendo que a bactéria Gram positiva (S. aureus) mostrou-se mais susceptível aos óleos testados que a Gram negativa (E. coli).

Antimicrobial Susceptibility ofEscherichia coliStrains Isolated fromAlouattaspp. Feces to Essential Oils

“…Our results differed from those found by other researchers, who observed antimicrobial activity in these oils against Gram-positive and Gram-negative bacteria [10, 13, 14, 16]. Studies indicate that how essential oils are obtained, the season, and geographic distribution are factors that can change the composition of these oils and alter their antimicrobial properties [28, 29], thus explaining the different results obtained in a number of studies on plant essential oils.…”

Antimicrobial Efficacy and Chemical Properties of Caryophyllus aromaticus and Origanum majorana Essential Oils Against Foodborne Bacteria Alone and in Combination

“…In two similar studies, the MIC value of clove EO against S. aureus was reported to be 0.09% (v/v). 42,43 Fu et al 14 found the MIC and MBC values of clove EO against foodborne microorganisms as 0.06%-0.50% (v/v) and 0.12%-0.50% (v/v), respectively. Contrary to the results of the present study, the lowest MIC and MBC values of clove EO against foodborne pathogens and spoilage bacteria were found to be1.25% and 2.5% (v/v) in the study of Hoque et al, respectively.…”

Development of Active Biodegradable Films: Starch Films Incorporated with Starch Nanoparticles and Oregano Essential Oil

“…Different from the present study, where antimicrobial films showed better effectiveness against Gram-positive bacteria (S. aureus), and it may be related to the form of obtaining the films and the interaction between the polymer and the essential oil. According to Silva [22], the antibacterial action of the essential oils varies significantly based on the bacteria, being the sensitivity higher for Grampositive than Gram-negative bacteria. One possible explanation for the observed differences in bacterial sensitivity may be differences in the bacterial wall structure, such as the presence of lipopolysaccharide in Gram-negative bacteria and the absence of Gram-positive bacteria, which may allow substances to enter or not in the bacterial cell, thus interfering with the action on the microorganism.…”