On the different growth conditions affecting silver antimicrobial efficacy on Listeria monocytogenes and Salmonella enterica

Martínez‐Abad, Antonio; Sánchez, Glòria; Lagarón, José M.; Ocio, M.J.

doi:10.1016/j.ijfoodmicro.2012.07.010

Cited by 28 publications

(15 citation statements)

References 48 publications

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“…Firstly, unstained cells could correspond to the cells that have undergone severe lysis and thus lost their nucleic acids, thereby rendering them unstainable [29]. These ‘ghost cells’ have been described by other researchers elsewhere [30, 31].…”

Section: Resultsmentioning

confidence: 99%

Fourier transform infra-red spectroscopy and flow cytometric assessment of the antibacterial mechanism of action of aqueous extract of garlic (Allium sativum) against selected probiotic Bifidobacterium strains

Booyens

Thantsha

2014

BMC Complement Altern Med

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BackgroundIt is generally reported that garlic (Allium sativum) harms pathogenic but not beneficial bacteria. Although numerous studies supporting the alleged garlic effects on pathogens are available, there are limited studies to prove this claim for beneficial bacteria. We have recently shown that garlic exhibits antibacterial activity against probiotic bifidobacteria. The aim of the current study was to elucidate the mechanism of action of garlic clove extract (GCE) on Bifidobacterium bifidum LMG 11041, B. longum LMG 13197 and B. lactis Bb12 using Fourier transform infrared (FT-IR) spectroscopy and flow cytometry.MethodsCultures (1 × 108 CFU ml-1) were individually incubated for 6 h at 37°C in garlic clove extract containing allicin at a corresponding predetermined minimum bactericidal concentration for each strain. For FTIR, an aliquot of each culture was deposited on CaF2 slide and vacuum dried. The slides were immediately viewed using a Bruker Vertex 70 V FT-IR spectrometer equipped with a Hyperion microscope and data analyzed using OPUS software (version 6, Bruker). Spectra were smoothed with a Savitsky-Goly function algorithim, base-line corrected and normalized. Samples for flow cytometry were stained using the Live/Dead BacLight bacterial viability kit L7012. Data compensation and analysis was performed using a BD FACSAria and FlowJo (version 7.6.1).ResultsFourier transform infrared spectroscopy showed changes in spectral features of lipids and fatty acids in cell membranes, proteins, polysaccharides and nucleic acids. Spectral data as per principle component analysis (PCA) revealed segregation of control and GCE-treated cells for all the tested bifidobacteria. Flow cytometry not only showed increase in numbers of membrane damaged and possibly lysed cells after GCE treatment, but also displayed diffuse light scatter patterns for GCE treated cells, which is evidence for changes to the size, granularity and molecular content of the cells.ConclusionGarlic has multiple target sites in bifidobacteria, penetrating the cell membrane and entering the cytoplasm, where it causes changes to carbohydrates, fatty acids, proteins and nucleic acids. These changes, for example, modification of membrane properties, may prevent exposed bifidobacteria from colonizing the intestinal mucosa. Loss of colonization potential would render them less efficient as probiotics.

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Section: Resultsmentioning

confidence: 99%

Fourier transform infra-red spectroscopy and flow cytometric assessment of the antibacterial mechanism of action of aqueous extract of garlic (Allium sativum) against selected probiotic Bifidobacterium strains

Booyens

Thantsha

2014

BMC Complement Altern Med

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“…La plata es uno de los aditivos con características antimicrobianas mayoritariamente utilizado en diversos materiales poliméricos como el agar (Ghosh et al, 2010;Rhim et al, 2013), alcohol de polivinilo (Bryaskova et al, 2010;Sedlarik et al, 2010), gelatina (Kanmani y Rhim, 2014) y mezclas de quitosan-celulosa (Lin et al, 2015), almidón-arcilla (Abreu et al, 2015) o quitosan-glutaraldehido (Vimala et al, 2011) para aplicaciones de empacado de alimentos (Martínez-Abad et al, 2012). Sin embargo, no hay casi estudios concernientes al desarrollo de BP a base de GBA cargadas de AgNPs y su comportamiento físico-mecánico.…”

Section: Introductionunclassified

Biopelículas de Gelana Cargadas con Nanopartículas de Plata: Propiedades Físico Mecánicas, Antimicrobianas y de Barrera

2017

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ResumenSe elaboraron biopelículas a base de gelana de bajo acilo cargadas con nanopartículas de plata (AgNPs) evaluando sus propiedades físico-mecánicas, antimicrobianas y de barrera, después de un almacenamiento de 3 semanas. La actividad antimicrobiana fue evaluada frente a bacterias de origen alimentario (Escherichia coli y Staphylococcus aureus) y dos hongos (Aspergillus sp y Penicillium sp). Los resultados permitieron determinar que el tiempo de almacenamiento influye en todas las propiedades evaluadas. Al incrementar el tiempo de almacenamiento se apreció una disminución en la resistencia a la tensión y en la transparencia. Además se presentó un incremento en el poder antimicrobiano y la permeabilidad al vapor de agua. Este comportamiento probablemente obedece a la lixiviación de iones plata, lo cual disminuye el número de enlaces presentes en la matriz polimérica. Tales resultados son prometedores y sugieren la posibilidad de utilizar biopelículas a base de gelana de bajo acilo como sistema de vehiculización de AgNPs para su liberación gradual manteniendo un efecto antimicrobiano sostenido. Palabras clave: biopelículas; goma gelana; nanopartículas de plata; permeabilidad; resistencia a la tensión Biofilms of Gellan Loaded with Silver Nanoparticles: Physico Mechanical, Antimicrobials and Barrier Properties AbstractBiofilms based on low acyl gellan loaded with silver nanoparticles (AgNPs) were tested, evaluating their physical-mechanical, antimicrobial and barrier properties after 3 weeks of storage. The antimicrobial activity was evaluated against food-borne bacteria (Escherichia coli and Staphylococcus aureus) and two fungi (Aspergillus sp and Penicillium sp). The results showed that the storage time influence all the evaluated properties. Increasing the storage time decreases the tensile strength and transparency values. Also, the antimicrobial power and the water vapor permeability increased. This behavior is probably due to the leaching of silver ions, which decreases the number of bonds present in the polymer matrix. Such results are promising and suggest the possibility of using biofilms based on low acyl gellan as a system for the vehiculation of AgNPs for their gradual release while maintaining a sustained antimicrobial effect.

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“…It is common knowledge that heavy metal ions cause inhibition of microorganism (bacterial) growth, therefore they are often incorporated into different kinds of materials to ensure antimicrobial activity [22,23]. The growth curves method serves as a tool to evaluate antimicrobial activity, as the effect of heavy metal ions on bacterial strains such as Staphylococcus aureus in this experiment [24,25,26].…”

Section: Resultsmentioning

confidence: 99%

Lead Ions Encapsulated in Liposomes and Their Effect on Staphylococcus aureus

Kenšová

Blažková

Konečná

et al. 2013

IJERPH

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The aim of the study was the preparation of a liposome complex with encapsulated lead ions, which were electrochemically detected. In particular, experiments were focused on the potential of using an electrochemical method for the determination of free and liposome-encapsulated lead and determination of the encapsulation efficiency preventing the lead toxicity. Primarily, encapsulation of lead ions in liposomes and confirmation of successful encapsulation by electrochemical methods was done. Further, the reduction effect of the liposome matrix on the detected electrochemical signal was monitored. Besides encapsulation itself, comparison of toxicity of free lead ions and lead ions encapsulated in liposome was tested. The calculated IC50 values for evaluating the lead cytotoxicity showed significant differences between the lead enclosed in liposomes (28 µM) and free lead ions (237 µM). From the cytotoxicity studies on the bacterial strain of S. aureus it was observed that the free lead ions are less toxic in comparison with lead encapsulated in liposomes. Liposomes appear to be a suitable carrier of various substances through the inner cavity. Due to the liposome structure the lead enclosed in the liposome is more easily accepted into the cell structure and the toxicity of the enclosed lead is higher in comparison to free lead ions.

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On the different growth conditions affecting silver antimicrobial efficacy on Listeria monocytogenes and Salmonella enterica

Cited by 28 publications

References 48 publications

Fourier transform infra-red spectroscopy and flow cytometric assessment of the antibacterial mechanism of action of aqueous extract of garlic (Allium sativum) against selected probiotic Bifidobacterium strains

Fourier transform infra-red spectroscopy and flow cytometric assessment of the antibacterial mechanism of action of aqueous extract of garlic (Allium sativum) against selected probiotic Bifidobacterium strains

Biopelículas de Gelana Cargadas con Nanopartículas de Plata: Propiedades Físico Mecánicas, Antimicrobianas y de Barrera

Lead Ions Encapsulated in Liposomes and Their Effect on Staphylococcus aureus

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