415 research outputs found

    Distinct variation in vector competence among nine field populations of Aedes aegypti from a Brazilian dengue-endemic risk city

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    Background: In Brazil, dengue epidemics erupt sporadically throughout the country and it is unclear if outbreaks may initiate a sustainable transmission cycle. There are few studies evaluating the ability of Brazilian Aedes aegypti populations to transmit dengue virus (DENV). The aim of this study was to compare DENV susceptibility of field-captured Ae. aegypti populations from nine distinct geographic areas of the city of Belo Horizonte in 2009 and 2011. Infection Rate (IR), Vector Competence (VC) and Disseminated Infection Rate (DIR) were determined. Methods: Aedes aegypti eggs from each region were collected and reared separately in an insectary. Adult females were experimentally infected with DENV-2 and the virus was detected by qPCR in body and head samples. Data were analyzed with the Statistical Package for the Social Sciences version 17. Results: IR varied from 40.0% to 82.5% in 2009 and 60.0% to 100.0% in 2011. VC ranged from 25.0% to 77.5% in 2009 and 25.0% to 80.0% in 2011. DIR oscillated from 68.7% to 100.0% in 2009 and 38.4% to 86.8 in 2011. When the results were evaluated by a logistic model using IR as covariate, North, Barreiro, South-Central and Venda Nova showed the strongest association in 2009. In 2011, a similar association was observed for South-Central, Venda Nova, West and Northeast regions. Using VC as covariate, South-Central and Venda Nova showed the most relevant association in 2009. In 2011, South-Central, Venda Nova and Barreiro presented the greatest revelation associations. When DIR data were analyzed by logistic regression models, Pampulha, South-Central, Venda Nova, West, Northeast and East (2009) as well as South-Central, Venda Nova and West (2011) were the districts showing the strongest associations. Conclusions: We conclude that Ae. aegypti populations from Belo Horizonte exhibit wide variation in vector competence to transmit dengue. Therefore, vector control strategies should be adapted to the available data for each region. Further analysis should be conducted to better understand the reasons for this large variability in vector competence and how these parameters correlate with epidemiological findings in subsequent years

    The influence of time and irrigant refreshment on biofilm removal from lateral morphological features of simulated root canals

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    Aim: To evaluate the effect of irrigant refreshment and exposure time of a 2% sodium hypochlorite solution (NaOCl) on biofilm removal from simulated lateral root canal spaces using two different flow rates. Methodology: A dual-species biofilm was formed by a Constant Depth Film Fermenter (CDFF) for 96 h in plug inserts with anatomical features resembling an isthmus or lateral canal-like structures. The inserts were placed in a root canal model facing the main canal. NaOCl 2% and demineralized water (control group) were used as irrigant solutions. Both substances were applied at a flow rate of 0.05 and 0.1 mL s−1. The samples were divided into three groups with zero, one or two refreshments in a total exposure time of 15 min. A three-way analysis of variance (anova) was performed to investigate the interaction amongst the independent variables and the effect of consecutive irrigant refreshment on percentage of biofilm removal. A Tukey post hoc test was used to evaluate the effect of each independent variable on percentage biofilm removal in the absence of statistically significant interactions. Results: For the lateral canal, NaOCl removed significantly more biofilm irrespective of the number of refreshments and exposure time (P = 0.005). There was no significant effect in biofilm removal between the consecutive irrigant refreshments measured in the same biofilm. For the isthmus, NaOCl removed significantly more biofilm irrespective of the number of refreshments and exposure time; both NaOCl and a high flow rate removed significantly more biofilm when the exposure time was analysed (P = 0.018 and P = 0.029, respectively). Evaluating the effect of consecutive irrigant refreshment on the same biofilm, 2% NaOCl, 0.1 mL s−1 flow rate and one or two refreshments removed significant more biofilm (P = 0.04, 0.034 and 0.003, <0.001, respectively). Conclusions: In this model, refreshment did not improve biofilm removal from simulated lateral root canal spaces. NaOCl removed more biofilm from the lateral canal- and isthmus-like structure. A higher flow rate removed significantly more biofilm from the isthmus-like structure. There was always remaining biofilm left after the irrigation procedures

    CaracterizaciĂłn del HLA en una familia colombiana endogĂĄmica con sĂ­ndrome de Usher

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    Resumen El sĂ­ndrome de Usher es una enfermedad autosĂłmica recesiva que se caracteriza por presentar retinitis pigmentosa, hipoacusia neurosensorial congĂ©nita y disfunciĂłn vestibular. El propĂłsito de este trabajo es realizar la caracterizaciĂłn de hla en una familia colombiana endogĂĄmica que presenta sĂ­ndrome de Usher. La metodologĂ­a consiste en que con un previo consentimiento informado se realizĂł una genealogĂ­a de la familia y a cuatro pacientes confirmados clĂ­nicamente con sĂ­ndrome de Usher y a cuatro fenotĂ­picamente sanos se les tomĂł 5 ml de sangre perifĂ©rica en tubos de venopunciĂłn con edta para luego realizar el aislamiento del dna por la tĂ©cnica de salting out, conservados en buffer te a -8 °C y ajustada la muestra a una concentraciĂłn de 8 ÎŒg/ml. Posteriormente a travĂ©s de la tĂ©cnica de pcr-ssp de mediana resoluciĂłn se caracterizaron los antĂ­genos de hla *a, *b, *drb1 y *dqb1. Los resultados obtenidos indican que la familia oriunda del Departamento del Huila presenta una marcada endogamia detectĂĄndose que todos los hermanos afectados, sus padres son hermanos tambiĂ©n y una de las parejas a su vez tuvo una niña afectada, por lo que sus abuelos y padres son hermanos. En lo referente al hla, los alelos mĂĄs frecuentemente encontrados fueron a30 b42 dr1 dq5 y a3 b45 dr12 y dq7, que no estĂĄn asociados a la enfermedad. Estos resultados sugieren que dada la endogamia que muestra esta familia se presenta una gran acumulaciĂłn de polimorfismos y mutaciones, por lo que es necesario realizar un proceso de asesorĂ­a genĂ©tica para disminuir el riesgo de recurrencia. Abstract Usher syndrome is an autosomal recessive disease characterized by retinitis pigmentosa, congenital sensorineural hearing loss and vestibular dysfunction. The purpose of this work was to characterize hla in an inbred Colombian family that presents Usher Syndrome. The Methodology consisted in that a genealogy of the family was made and previous informed consent, from four patients clinically confirmed with Usher Syndrome and four phenotypically healthy patients 5 ml of peripheral blood were taken in venipuncture tubes with edta and then the dna isolation was performed with the technique of salting out, preserved in te buffer at -8 °C and adjusted the sample to a concentration of 8 ÎŒg/ml. The hla *A, *B, *DRB1 and *DQB1 antigens were then characterized by the medium-resolution pcr-ssp techniqu

    CaracterizaciĂłn del HLA en una familia colombiana endogĂĄmica con sĂ­ndrome de Usher

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    Resumen El sĂ­ndrome de Usher es una enfermedad autosĂłmica recesiva que se caracteriza por presentar retinitis pigmentosa, hipoacusia neurosensorial congĂ©nita y disfunciĂłn vestibular. El propĂłsito de este trabajo es realizar la caracterizaciĂłn de hla en una familia colombiana endogĂĄmica que presenta sĂ­ndrome de Usher. La metodologĂ­a consiste en que con un previo consentimiento informado se realizĂł una genealogĂ­a de la familia y a cuatro pacientes confirmados clĂ­nicamente con sĂ­ndrome de Usher y a cuatro fenotĂ­picamente sanos se les tomĂł 5 ml de sangre perifĂ©rica en tubos de venopunciĂłn con edta para luego realizar el aislamiento del dna por la tĂ©cnica de salting out, conservados en buffer te a -8 °C y ajustada la muestra a una concentraciĂłn de 8 ÎŒg/ml. Posteriormente a travĂ©s de la tĂ©cnica de pcr-ssp de mediana resoluciĂłn se caracterizaron los antĂ­genos de hla *a, *b, *drb1 y *dqb1. Los resultados obtenidos indican que la familia oriunda del Departamento del Huila presenta una marcada endogamia detectĂĄndose que todos los hermanos afectados, sus padres son hermanos tambiĂ©n y una de las parejas a su vez tuvo una niña afectada, por lo que sus abuelos y padres son hermanos. En lo referente al hla, los alelos mĂĄs frecuentemente encontrados fueron a30 b42 dr1 dq5 y a3 b45 dr12 y dq7, que no estĂĄn asociados a la enfermedad. Estos resultados sugieren que dada la endogamia que muestra esta familia se presenta una gran acumulaciĂłn de polimorfismos y mutaciones, por lo que es necesario realizar un proceso de asesorĂ­a genĂ©tica para disminuir el riesgo de recurrencia. Abstract Usher syndrome is an autosomal recessive disease characterized by retinitis pigmentosa, congenital sensorineural hearing loss and vestibular dysfunction. The purpose of this work was to characterize hla in an inbred Colombian family that presents Usher Syndrome. The Methodology consisted in that a genealogy of the family was made and previous informed consent, from four patients clinically confirmed with Usher Syndrome and four phenotypically healthy patients 5 ml of peripheral blood were taken in venipuncture tubes with edta and then the dna isolation was performed with the technique of salting out, preserved in te buffer at -8 °C and adjusted the sample to a concentration of 8 ÎŒg/ml. The hla *A, *B, *DRB1 and *DQB1 antigens were then characterized by the medium-resolution pcr-ssp techniqu

    Antimicrobial activity of ProRoot MTA in contact with blood

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    Dental materials based on Portland cement, which is used in the construction industry have gained popularity for clinical use due to their hydraulic properties, the interaction with tooth tissue and their antimicrobial properties. The antimicrobial properties are optimal in vitro. However in clinical use contact with blood may affect the antimicrobial properties. This study aims to assess whether antimicrobial properties of the Portland cement-based dental cements such as mineral trioxide aggregate (MTA) are also affected by contact with blood present in clinical situations. ProRoot MTA, a Portland cement-based dental cement was characterized following contact with water, or heparinized blood after 1 day and 7 days aging. The antimicrobial activity under the mentioned conditions was assessed using 3 antimicrobial tests: agar diffusion test, direct contact test and intratubular infection test. MTA in contact with blood was severely discoloured, exhibited an additional phosphorus peak in elemental analysis, no calcium hydroxide peaks and no areas of bacterial inhibition growth in the agar diffusion test were demonstrated. ProRoot MTA showed limited antimicrobial activity, in both the direct contact test and intratubular infection test. When aged in water ProRoot MTA showed higher antimicrobial activity than when aged in blood. Antimicrobial activity reduced significantly after 7 days. Further assessment is required to investigate behaviour in clinical situations.ERDF (Malta) for the financing of the testing equipment through the project: “Developing an Interdisciplinary Material Testing and Rapid Prototyping R&D Facility” (Ref. no. 012)

    I–II Loop Structural Determinants in the Gating and Surface Expression of Low Voltage-Activated Calcium Channels

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    The intracellular loops that interlink the four transmembrane domains of Ca2+- and Na+-channels (Cav, Nav) have critical roles in numerous forms of channel regulation. In particular, the intracellular loop that joins repeats I and II (I–II loop) in high voltage-activated (HVA) Ca2+ channels possesses the binding site for CavÎČ subunits and plays significant roles in channel function, including trafficking the α1 subunits of HVA channels to the plasma membrane and channel gating. Although there is considerable divergence in the primary sequence of the I–II loop of Cav1/Cav2 HVA channels and Cav3 LVA/T-type channels, evidence for a regulatory role of the I–II loop in T-channel function has recently emerged for Cav3.2 channels. In order to provide a comprehensive view of the role this intracellular region may play in the gating and surface expression in Cav3 channels, we have performed a structure-function analysis of the I–II loop in Cav3.1 and Cav3.3 channels using selective deletion mutants. Here we show the first 60 amino acids of the loop (post IS6) are involved in Cav3.1 and Cav3.3 channel gating and kinetics, which establishes a conserved property of this locus for all Cav3 channels. In contrast to findings in Cav3.2, deletion of the central region of the I–II loop in Cav3.1 and Cav3.3 yielded a modest increase (+30%) and a reduction (−30%) in current density and surface expression, respectively. These experiments enrich our understanding of the structural determinants involved in Cav3 function by highlighting the unique role played by the intracellular I–II loop in Cav3.2 channel trafficking, and illustrating the prominent role of the gating brake in setting the slow and distinctive slow activation kinetics of Cav3.3

    Spatio-temporal distribution of pyrethroids in soil in Mediterranean paddy fields

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    [EN] The demand of rice by the increase in population in many countries has intensified the application of pesticides and the use of poor quality water to irrigate fields. The terrestrial environment is one compartment affected by these situations, where soil is working as a reservoir, retaining organic pollutants. Therefore, it is necessary to develop methods to determine insecticides in soil and monitor susceptible areas to be contaminated, applying adequate techniques to remediate them. Materials and methods This study investigates the occurrence of ten pyrethroid insecticides (PYs) and its spatio-temporal variance in soil at two different depths collected in two periods (before plow and during rice production), in a paddy field area located in the Mediterranean coast. Pyrethroids were quantified using gas chromatography mass spectrometry (GC MS) after ultrasound-assisted extraction with ethyl acetate. The results obtained were assessed statistically using non-parametric methods, and significant statistical differences (p&#8201;<&#8201;0.05) in pyrethroids content with soil depth and proximity to wastewater treatment plants were evaluated. Moreover, a geographic information system (GIS) was used to monitor the occurrence of PYs in paddy fields and detect risk areas. Results and discussion Pyrethroids were detected at concentrations &#8804;57.0 ng g&#8722;1 before plow and &#8804;62.3 ng g&#8722;1 during rice production, being resmethrin and cyfluthrin the compounds found at higher concentrations in soil. Pyrethroids were detected mainly at the top soil, and a GIS program was used to depict the obtained results, showing that effluents from wastewater treatment plants (WWTPs) were the main sources of soil contamination. No toxic effects were expected to soil organisms, but it is of concern that PYs may affect aquatic organisms, which represents the worst case scenario. Conclusions A methodology to determine pyrethroids in soil was developed to monitor a paddy field area. The use of water from WWTPs to irrigate rice fields is one of the main pollution sources of pyrethroids. It is a matter of concern that PYs may present toxic effects on aquatic organisms, as they can be desorbed from soil. Phytoremediation may play an important role in this area, reducing the possible risk associated to PYs levels in soil.Authors wish to thank INIA for the predoctoral fellowship (R. Aznar) and Spanish Ministry of Economy and Competitiveness RTA2014-00012-C03-01 for financial support and Jonathan Villanueva Martin for his contribution to this work.Aznar, R.; Moreno-RamĂłn, H.; Albero, B.; SĂĄnchez Brunete, C.; Tadeo, JL. (2016). Spatio-temporal distribution of pyrethroids in soil in Mediterranean paddy fields. Journal of Soils and Sediments. 17(5):1503-1513. https://doi.org/10.1007/s11368-016-1417-2S15031513175Albaseer SS, Rao RN, Swamy YV, Mukkanti K (2010) An overview of sample preparation and extraction of synthetic pyrethroids from water, sediment and soil. J Chromatogr A 1217(35):5537–5554Alonso MB, Feo ML, Corcellas C, Vidal LG, Bertozzi CP, Marigo J, Secchi ER, Bassoi M, Azevedo AF, Dorneles PR, Torres JPM, Lailson-Brito J, Malm O, Eljarrat E, Barcelo D (2012) Pyrethroids: a new threat to marine mammals? Environ Int 47:99–106Amweg EL, Weston DP, Ureda NM (2005) Use and toxicity of pyrethroid pesticides in the Central Valley, California, USA. Environ Toxicol Chem 24(4):966–972Arias-Estevez M, Lopez-Periago E, Martinez-Carballo E, Simal-Gandara J, Mejuto JC, Garcia-Rio L (2008) The mobility and degradation of pesticides in soils and the pollution of groundwater resources. Agric Eco Environ 123(4):247–260Aznar R, Albero B, Sanchez-Brunete C, Miguel E, Tadeo JL (2014) Multiresidue analysis of insecticides and other selected environmental contaminants in poultry manure by gas chromatography/mass spectrometry. J AOAC Int 97(4):978–986Campo J, Masia A, Blasco C, Pico Y (2013) Occurrence and removal efficiency of pesticides in sewage treatment plants of four Mediterranean River Basins. J Hazard Mater 263:146–157European Commission (2002) Review report for the active substance Cyfluthrin, 6843/VI/97-finalEuropean Commission (2004) Review report for the active substance α-Cypermethrin, SANCO/4335/2000-finalEuropean Commission (2005) Review report for the active substance Esfenvalerate, 6846/VI/97-finalFeo ML, Ginebreda A, Eljarrat E, Barcelo D (2010) Presence of pyrethroid pesticides in water and sediments of Ebro River Delta. J Hydrol 393(3-4):156–162Fojut TL, Palumbo AJ, Tjeerdema RS (2012) Aquatic life water quality criteria derived via the UC Davis method: II. Pyrethroid insecticides. Rev Environ Contam Toxicol 216:51–103Gan J, Lee SJ, Liu WP, Haver DL, KAbashima JN (2005) Distribution and persistence of pyrethroids in runoff sediments. J Environ Qual 34:836–841Hill IR (1985) Aquatic organisms and pyrethroids. Pestic Sci 27:429–465Huang LM, Thompson A, Zhang GL, Chen LM, Han GZ, Gong ZT (2015) The use of chronosequences in studies of paddy soil evolution: a review. Geoderma 237:199–210Katagi T (2004) Photodegradation of pesticides on plant and soil surfaces. Rev Environ Contam Toxicol 182:1–189Laskowski DA (2002) Physical and chemical properties of pyrethroids. Rev Environ Contam Toxicol 174:49–170Mahabali S, Spagnoghe P (2014) Mitigation of two insecticides by wetlands plants: feasibility study for the treatment of agricultural runoff in Suriname (South America). Water Air Soil Pollut 225:1771Maund SJ, Hamer MJ, Lane MCG, Farrelly E, Rapley JH, Goggin UM, Gentle WE (2002) Partitioning, bioavailability, and toxicity of the pyrethroid insecticide cypermethrin in sediments. Environ Toxicol Chem 21(1):9–15Maund SJ, Campbell PJ, Giddings JM, Hamer MJ, Henry K, Pilling ED, Warinton JS, Wheeler JR (2012) Ecotoxicology of synthetic pyrethroids. Top Curr Chem 314:137–165Money E, Carter GP, Serre ML (2009) Using river distances in the space/time estimation of dissolved oxygen along two impaired river networks in New Jersey. Water Res 43(7):1948–1958Moore MT, Cooper CM, Smith S, Jr Cullum RF, Knight SS, Locke MA, Bennett ER (2009) Mitigation of two pyrethroid insecticides in Mississippi Delta constructed wetland. Environ Pollut 157:250–256Moreno-RamĂłn H, MarquĂ©s-Mateu A, Ibåñez-Asensio S, Gisbert JM (2015) Wetland soils under rice management and seawater intrusion: characterization and classification. 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    Decolonisation of MRSA, S. aureus and E. coli by Cold-Atmospheric Plasma Using a Porcine Skin Model In Vitro

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    In the last twenty years new antibacterial agents approved by the U.S. FDA decreased whereas in parallel the resistance situation of multi-resistant bacteria increased. Thus, community and nosocomial acquired infections of resistant bacteria led to a decrease in the efficacy of standard therapy, prolonging treatment time and increasing healthcare costs. Therefore, the aim of this work was to demonstrate the applicability of cold atmospheric plasma for decolonisation of Gram-positive (Methicillin-resistant Staphylococcus aureus (MRSA), Methicillin-sensitive Staphylococcus aureus) and Gram-negative bacteria (E. coli) using an ex vivo pig skin model. Freshly excised skin samples were taken from six month old female pigs (breed: Pietrain). After application of pure bacteria on the surface of the explants these were treated with cold atmospheric plasma for up to 15 min. Two different plasma devices were evaluated. A decolonisation efficacy of 3 log10 steps was achieved already after 6 min of plasma treatment. Longer plasma treatment times achieved a killing rate of 5 log10 steps independently from the applied bacteria strains. Histological evaluations of untreated and treated skin areas upon cold atmospheric plasma treatment within 24 h showed no morphological changes as well as no significant degree of necrosis or apoptosis determined by the TUNEL-assay indicating that the porcine skin is still vital. This study demonstrates for the first time that cold atmospheric plasma is able to very efficiently kill bacteria applied to an intact skin surface using an ex vivo porcine skin model. The results emphasize the potential of cold atmospheric plasma as a new possible treatment option for decolonisation of human skin from bacteria in patients in the future without harming the surrounding tissue

    Biosorption and Biomineralization of U(VI) by the Marine Bacterium Idiomarina loihiensis MAH1: Effect of Background Electrolyte and pH

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    The main goal of this study is to compare the effects of pH, uranium concentration, and background electrolyte (seawater and NaClO4 solution) on the speciation of uranium(VI) associated with the marine bacterium Idiomarina loihiensis MAH1. This was done at the molecular level using a multidisciplinary approach combining X-ray Absorption Spectroscopy (XAS), Time-Resolved Laser-Induced Fluorescence Spectroscopy (TRLFS), and High Resolution Transmission Electron Microscopy (HRTEM). We showed that the U(VI)/bacterium interaction mechanism is highly dependent upon pH but also the nature of the used background electrolyte played a role. At neutral conditions and a U concentration ranging from 5·10−4 to 10−5 M (environmentally relevant concentrations), XAS analysis revealed that uranyl phosphate mineral phases, structurally resembling meta-autunite [Ca(UO2)2(PO4)2 2–6H2O] are precipitated at the cell surfaces of the strain MAH1. The formation of this mineral phase is independent of the background solution but U(VI) luminescence lifetime analyses demonstrated that the U(VI) speciation in seawater samples is more intricate, i.e., different complexes were formed under natural conditions. At acidic conditions, pH 2, 3 and 4.3 ([U] = 5·10−4 M, background electrolyte = 0.1 M NaClO4), the removal of U from solution was due to biosorption to Extracellular Polysaccharides (EPS) and cell wall components as evident from TEM analysis. The LIII-edge XAS and TRLFS studies showed that the biosorption process observed is dependent of pH. The bacterial cell forms a complex with U through organic phosphate groups at pH 2 and via phosphate and carboxyl groups at pH 3 and 4.3, respectively. The differences in the complexes formed between uranium and bacteria on seawater compared to NaClO4 solution demonstrates that the actinide/microbe interactions are influenced by the three studied factors, i.e., the pH, the uranium concentration and the chemical composition of the solution.This work was funded by the grants CGL2009-09760 and CGL2012-36505 (Ministerio de Ciencia e InnovaciĂłn), and RNM 3943 (Junta de AndalucĂ­a), Spain

    In vitro antibacterial activity of some plant essential oils

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    BACKGROUND: To evaluate the antibacterial activity of 21 plant essential oils against six bacterial species. METHODS: The selected essential oils were screened against four gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus vulgaris) and two gram-positive bacteria Bacillus subtilis and Staphylococcus aureus at four different concentrations (1:1, 1:5, 1:10 and 1:20) using disc diffusion method. The MIC of the active essential oils were tested using two fold agar dilution method at concentrations ranging from 0.2 to 25.6 mg/ml. RESULTS: Out of 21 essential oils tested, 19 oils showed antibacterial activity against one or more strains. Cinnamon, clove, geranium, lemon, lime, orange and rosemary oils exhibited significant inhibitory effect. Cinnamon oil showed promising inhibitory activity even at low concentration, whereas aniseed, eucalyptus and camphor oils were least active against the tested bacteria. In general, B. subtilis was the most susceptible. On the other hand, K. pneumoniae exhibited low degree of sensitivity. CONCLUSION: Majority of the oils showed antibacterial activity against the tested strains. However Cinnamon, clove and lime oils were found to be inhibiting both gram-positive and gram-negative bacteria. Cinnamon oil can be a good source of antibacterial agents
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