Synergy in preservative combinations

Denyer, Stephen Paul; Hugo, W. B.; Harding, Valerie D.

doi:10.1016/0378-5173(85)90166-8

Cited by 43 publications

(31 citation statements)

References 22 publications

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“…Research into antimicrobial synergy essentially uses a single axiom as a base – that a synergy may occur if antimicrobials with different target sites are blended together (Hugbo 1976a; Denyer et al. 1985; Denyer 1990).…”

Section: Introductionmentioning

confidence: 99%

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Theory of antimicrobial combinations: biocide mixtures - synergy or addition?

et al. 2003

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Aims:To demonstrate the effect that non-linear dose responses have on the appearance of synergy in mixtures of antimicrobials. Methods and Results: A mathematical model, which allows the prediction of the efficacy of mixtures of antimicrobials with non-linear dose responses, was produced. The efficacy of antimicrobial mixtures that would be classified as synergistic by time-kill methodology was shown to be a natural consequence of combining antimicrobials with non-linear dose responses. Conclusions: The effectiveness of admixtures of biocides and other antimicrobials with non-linear dose responses can be predicted. If the dose response (or dilution coefficient) of any biocidal component, in a mixture, is other than one, then the time-kill methodology used to ascertain the existence of synergy in antimicrobial combinations is flawed. Significance and Impact of the Study: The kinetic model developed allows the prediction of the efficacy of antimicrobial combinations. Combinations of known antimicrobials, which reduce the time taken to achieve a specified level of microbial inactivation, can be easily assessed once the kinetic profile of each component has been obtained. Most patented cases of antimicrobial synergy have not taken into account the possible effect of non-linear dose responses of the component materials. That much of the earlier literature can now be predicted, suggests that future cases will require more thorough proof of the alleged synergy.

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Section: Introductionmentioning

confidence: 99%

“…1995). The synergy between the preservatives chlorocresol and phenethyl alcohol (PeA) is rationalized on the basis of differing cellular targets (Denyer et al. 1985).…”

Section: Introductionmentioning

confidence: 99%

Theory of antimicrobial combinations: biocide mixtures - synergy or addition?

et al. 2003

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“…To make certain that the true mechanism of the reaction is synergistic, the values of 2f(a) and 2f(b) should also be determined and compared with the value of f(a + b), and show that 2f(a) > f(a + b) and 2f(b) > f(a + b). The concept of synergism and the correct means for determining whether the effect is synergistic, additive, or antagonistic has been described in several reviews on this subject (28,30), and papers on its applications to various agents (31-33), theoretical treatment, and modeling (34)(35)(36).…”

Section: Synergismmentioning

confidence: 99%

Synergistic reaction of silver nitrate, silver nanoparticles, and methylene blue against bacteria

Chen

Cesario

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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In this paper we describe the antibacterial effect of methylene blue, MB, and silver nitrate reacting alone and in combination against five bacterial strains including Serratia marcescens and Escherichia coli bacteria. The data presented suggest that when the two components are combined and react together against bacteria, the effects can be up to three orders of magnitude greater than that of the sum of the two components reacting alone against bacteria. Analysis of the experimental data provides proof that a synergistic mechanism is operative within a dose range when the two components react together, and additive when reacting alone against bacteria.bacteria | synergistic effect | methylene blue | silver ions B acterial infections cause countless deaths in humans and animals. The increasing resistance and immunity of many bacteria to antibiotics demands that an effective means for the inactivation of bacteria becomes available that can overcome or negate the mechanism that bacteria use to inactivate the reactive agents before they render their lethal action on those organisms. The two antibacterial agents that we used in this study were methylene blue (MB) and silver nitrate. Each of these alone is known to be an effective antibacterial agent. The data presented in this study show that they make a synergistic agent pair against the five bacteria studied. MB is used as a bacterial inactivator for skin treatment, dental therapy, and other areas in need of bacterial disinfection (1-3). MB is a cation, whereas in its reduced leuco form MB has a pK a of 5.8 and low ionization at neutral physiological pH. This enables bacteria to reduce and inactivate MB to the leuco form. In fact, the discoloration of MB has been an indication of the presence of bacteria. In its cationic form, MB irradiated with 630-680-nm light is used for cancer therapy and as an effective bactericidal and activating agent. MB is an effective antibacterial agent owing to its ability to generate a high concentration of singlet oxygen, 1 O 2 ( 1 Δ g ), and other reactive oxygen species, such as OH • radicals (ROS), when irradiated with red light, which in contrast to UV light does not harm humans or animals cells. Therefore, the MB bacterial inactivation process is very safe and effective owing to the high reactivity of ROS with bacterial outer-cell membrane. It is found that the photogenerated singlet oxygen reacts against tryptophan and other outer-membrane molecules, resulting in damage to the bacterial cell and inhibiting protein production. ROS may also create a hole in the bacterial cell wall, which allows MB radicals to penetrate through the bacterial membrane and attack DNA, forming dimers which prevent it from replicating and consequently induce bacterial inactivation. The photoreaction that generates singlet oxygen and OH • radicals proceeds as follows: i) MB in water solution is excited to the first singlet state MB*:MB + hν (660 nm) →MB*; ii) MB* decays to the triplet state 3 MB* with a lifetime of ∼10 −9 s: MB* → 3 MB*; iii) The tripl...

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“…Biocides have multiple applications. The extensive use of antiseptics and disinfectants has resulted in the emergence of bacterial resistance to antibiotics [6,7]. The extensive use of disinfectants has given rise to the appearance of Staphylococci resistant to disinfectants, in particular QACs, in dairy products.…”

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confidence: 99%

Antibacterial effect of zinc on benzalkonium chloride- tolerant and -sensitive smr+ Staphylococcus aureus

Dadook¹,

Ashkar²,

Irian³

2014

International Journal of Cellular and Molecular Biotechnology

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Zn2+ is an important biological element with toxic effects. smr + Staphylococcus aureus resistant to quaternary ammonium compounds (QACs) have emerged due to a widespread consumption of QACcontaining biocides. This study aimed at assessing zinc sensitivity of Staphylococcus aureus in comparison to Benzalkonium chloride-tolerant and sensitive smr + strains. Clinical and dairy samples of Staphylococcus aureus were isolated using Mannitol salt agar (MSA) medium at 37 ºC for 48 hours and subjected to both biochemical and morphological characterization. The presence of smr gene was confirmed by PCR, while Macrodilution broth method was applied for MIC determination. A total of 9 smr + Benzalkonium chloride-tolerant Staphylococcus aureus strains were isolated from both clinical and dairy samples. Effect of zinc was determined for 20 randomly selected Staphylococcus strains, and MIC values were reported for all 20 strains at a zinc concentration of 20ppm. It was concluded that a zinc concentration greater than 20ppm has an antimicrobial effect on Staphylococcus aureus strains, and that zinc can be used as an antimicrobial agent for biocide resistant strains.

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Synergy in preservative combinations

Cited by 43 publications

References 22 publications

Theory of antimicrobial combinations: biocide mixtures - synergy or addition?

Theory of antimicrobial combinations: biocide mixtures - synergy or addition?

Synergistic reaction of silver nitrate, silver nanoparticles, and methylene blue against bacteria

Antibacterial effect of zinc on benzalkonium chloride- tolerant and -sensitive smr+ Staphylococcus aureus

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