Antibacterial activity synergistic effects

Antimicrobial activity potassium sorbate is predominantly used as an antifungal preservative although it also has antibacterial properties. Similarly to sorbic acid, the antimicrobial activity is dependent on the degree of dissociation there is practically no antibacterial activity above pH 6. Preservative efficacy is increased with increasing temperature, and increasing concentration of potassium sorbate. The efficacy of potassium sorbate is also increased when used in combination with other antimicrobial preservatives or glycols since synergistic effects occur. Reported minimum inhibitory concentrations (MICs) at the pH values indicated are shown in Table... 

A comparison of the antibacterial activity of normal chitosan, nanochitosan, and silver-loaded nanochitosan applied on woven polyester fabrics showed that the nanoparticle form of chitosan imparted much enhanced antibacterial activity, as indicated by a reduction in minimum inhibitory concentration (MIC) from 0.5% to 0.01% (Wazed Ali et al., 2011). The silver-loaded chitosan nanoparticle showed a further increase in activity (MIC 0.001%) due to the synergistic effect of Ag and chitosan nanoparticles. These particles additionally show a release mechanism as evident from a clear zone of inhibition (Figure 5.4(a—d)). 

This nuclear analogue of cephalosporins was screened for antibacterial activity against three strains Alcaligtnes faecalis. Staphylococcus aureus and Salmonella typhy, with cephalosporin C as control antibacterial agent. Activity was not observed at 1 mg/ml, nor a synergistic effect with cephalosporin C. 

Keywords Flavonoids Antibacterial activity Antifungal activity MRS A strains Synergistic effect... 

Antibacterial Activity of a Combination of Flavonoids or a Combination of Flavonoids and Antibiotics (Synergistic Effect)... 

Gillissen [104] finds that the antibacterial action of tyrothricin is influenced by the presence of solubilizers. Cationic surfactants have a synergistic effect (as mentioned above) on its activity against Gram-positive and Gram-negative bacteria, whereas polysorbate 80 inhibits its activity. It is thus important that these effects are borne in mind, and a compromise must be found between the stability and incompatibility characteristics of the solution and the activity of the product. The complexity of the situation is revealed by the fact that the activity of bacitracin is enhanced by the presence of cationic and non-ionic surfactants [106] but decreased by anionic agents. The effect of non-ionic surfactants on the bactericidal activity of tyrothricin has been measured [107]. Some results are shown in Table 6.11. 

Q85 The combination of antibacterial agents in co-trimoxazole presents a synergistic activity. Co-trimoxazole is associated with rare but serious side-effects. 

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