Antimicrobial Effect Of Nisin Research Articles

Nisin activity against methicillin-resistant and methicillin-sensitive Staphylococcus aureus and risk of resistance acquisition

The objective of this study was to analyze the antimicrobial effect of nisin against MRSA (Methicillin-Resistant Staphylococcus aureus) and MSSA (Methicillin-Sensitive Staphylococcus aureus), and at the same time examine the possibility of the bacteria to develope nisin resistance. The antimicrobial susceptibility of the strains was tested using the agar diffusion and/or microdilution methods. To select nisin-resistant strains, bacteria were grown consecutively at sublethal concentrations of the bacteriocin. Nisin showed bactericidal activity against most of the tested strains. MRSA required higher doses of bacteriocin compared to MSSA both for inhibition and cell death. However, transfers in the presence of nisin could completely eliminate nisin activity with an increase in minimal inhibitory concentration value of up to 250 times. Nisin-resistance could be maintained in MRSA and MSSA even in the absence of the bacteriocin. Nisin resistance affected antibiotic susceptibility of both MRSA and MSSA to mainly Cefoxitin, Oxacillin, and Erythromycin. These results indicate that nisin-resistance is a complex trait among MSSA and MRSA and must be elucidated before the therapeutic recommendation of nisin to treat infections caused by these bacterial species.

Antimicrobial effect of nisin in processed cheese - Quantification of residual nisin by LC-MS/MS and development of new growth and growth boundary model for Listeria monocytogenes

This study tested the hypothesis that growth of Listeria monocytogenes in processed cheese with added nisin can be predicted from residual nisin A concentrations in the final product after processing. A LC-MS/MS method and a bioassay were studied to quantify residual nisin A concentrations and a growth and growth boundary model was developed to predict the antilisterial effect in processed cheese. 278 growth rates were determined in broth for 11 L. monocytogenes isolates and used to determine 13 minimum inhibitory concentration (MIC) values for nisin between pH 5.5 and 6.5. To supplement these data, 67 MIC-values at different pH-values were collected from the scientific literature. A MIC-term was developed to describe the effect of pH on nisin MIC-values. An available growth and growth boundary model (doi: https://doi.org/10.1016/j.fm.2019.103255) was expanded with the new MIC-term for nisin to predict growth in processed cheese. To generate data for model evaluation and further model development, challenge tests with a total of 45 growth curves, were performed using processed cheese. Cheeses were formulated with 11.2 or 12.0 ppm of nisin A and heat treated to obtain residual nisin A concentrations ranging from 0.56 to 5.28 ppm. Below 15 °C, nisin resulted in extended lag times. A global regression approach was used to fit all growth curves determined in challenge tests. This was obtained by combining the secondary growth and growth boundary model including the new term for the inhibiting effect of nisin on μmax with the primary logistic growth model with delay. This model appropriately described the growth inhibiting effect of residual nisin A and showed that relative lag times depended on storage temperatures. With residual nisin A concentrations, other product characteristics and storage temperature as input the new model correctly predicted all observed growth and no-growth responses for L. monocytogenes. This model can support development of nisin A containing recipes for processed cheese that prevent growth of L. monocytogenes. Residual nisin A concentrations in processed cheese were accurately quantified by the developed LC-MS/MS method with recoveries of 83 to 110% and limits of detection and quantification being 0.04 and 0.13 ppm, respectively. The tested bioassay was less precise and nisin A recoveries varied for 53% to 94%.

Hurdle Effect of Antimicrobial Activity Achieved by Time Differential Releasing of Nisin and Chitosan Hydrolysates from Bacterial Cellulose.

We investigated the combined antimicrobial effect of nisin and chitosan hydrolysates (CHs) by regulating the antimicrobial reaction order of substances due to differential releasing rate from hydroxypropylmethylcellulose-modified bacterial cellulose (HBC). The minimum inhibitory concentration of nisin against Staphylococcus aureus and that of CHs against Escherichia coli were 6 IU and 200 μg/mL, respectively. Hurdle and additive effects in antimicrobial tests were observed when nisin was used 6 h before CH treatment against S. aureus; similar effects were observed when CH was used before nisin treatment against E. coli. Simultaneously combined treatment of nisin and CHs exhibited the low antimicrobial effect. HBC was then selected as the carrier for the controlled release of nisin and CHs. A 90% inhibition in the growth of S. aureus and E. coli was achieved when 30 IU-nisin-containing HBC and 62.5 μg/mL-CH-containing HBC were used simultaneously. The controlled release of nisin and CHs by using HBC minimized the interaction between nisin and CHs as well as increased the number of microbial targets.

Antimicrobial Effect of Nisin against Bacillus cereus in Beef Jerky during Storage.

The microbial distribution of raw materials and beef jerky, and the effect of nisin on the growth of Bacillus cereus inoculated in beef jerky during storage, were studied. Five strains of pathogenic B. cereus were detected in beef jerky, and identified with 99.8% agreement using API CHB 50 kit. To evaluate the effect of nisin, beef jerky was inoculated with approximately 3 Log CFU/g of B. cereus mixed culture and nisin (100 IU/g and 500 IU/g). During the storage of beef jerky without nisin, the number of mesophilic bacteria and B. cereus increased unlikely for beef jerky with nisin. B. cereus started to grow after 3 d in 100 IU nisin/g treatment, and after 21 d in 500 IU nisin/g treatment. The results suggest that nisin could be an effective approach to extend the shelf-life, and improve the microbial safety of beef jerky, during storage.

Inhibitory effects of nisin-coated multi-walled carbon nanotube sheet on biofilm formation from Bacillus anthracis spores

Multi-walled carbon nanotube (MWCNT) sheet was fabricated from a drawable MWCNT forest and then deposited on poly(methyl methacrylate) film. The film was further coated with a natural antimicrobial peptide nisin. We studied the effects of nisin coating on the attachment of Bacillus anthracis spores, the germination of attached spores, and the subsequent biofilm formation from attached spores. It was found that the strong adsorptivity and the super hydrophobicity of MWCNTs provided an ideal platform for nisin coating. Nisin coating on MWCNT sheets decreased surface hydrophobicity, reduced spore attachment, and reduced the germination of attached spores by 3.5 fold, and further inhibited the subsequent biofilm formation by 94.6% compared to that on uncoated MWCNT sheet. Nisin also changed the morphology of vegetative cells in the formed biofilm. The results of this study demonstrated that the anti-adhesion and antimicrobial effect of nisin in combination with the physical properties of carbon nanotubes had the potential in producing effective anti-biofilm formation surfaces.

Antimicrobial effect of nisin and carvacrol and competition between Bacillus cereus and Bacillus circulans in vacuum-packed potato puree

A study was undertaken to investigate the growth and competition between Bacillus cereus and B. circulans strains in both BHI and ready-to-eat potato puree. In addition, antimicrobial potential of supplemented nisin and carvacrol was evaluated against inoculated B. cereus and B. circulans strains. The accomplished growth inhibition was observed for both B. cereus and B. circulans, where B. circulans strains were more sensitive. MIC values were decreased by lowering the incubation temperature in separate applications of nisin and carvacrol, while the effect of combined application of nisin and carvacrol appeared to be more obvious at higher temperatures. The overall effect of interactions between spoilage and pathogenic Bacillus spp. was dependent on the psychrotrophic character of both cultures. The complete inhibition of B. circulans in the co-culture experiments corresponded to B. cereus population density of approximately 6 log units. Microbial challenge testing in potato puree showed that, at both 7 and 10°C, B. cereus TZ415 and B. circulans 4.1 could grow to high counts when no antimicrobial substances (nisin and carvacrol) were applied, while no visible spoilage occurred. A more pronounced antimicrobial activity of nisin and nisin–carvacrol combination was observed in potato puree compared to the BHI medium.

In Vitro Treatment of Different Isolates from Cattle Dung and Pig Slurry by Nisin

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Studies on the mode of action of nisin

The interference of the polypeptide antibiotic nisin with membrane function and murein synthesis was studied. The inhibition of the in vivo synthesis of murein in Bacillus subtilis and the resistance of Mycoplasma mycoides to nisin, suggest that the membrane may be excluded as a target. On the other hand a general inhibition of macromolecule syntheses in Micrococcus luteus supports the assumption that the cytoplasmic membrane is a target. In addition, an antagonistic effect on growth inhibition by nisin with both, cytoplasmic membranes and isolated phospholipid components of membranes was demonstrated. The lysis of phospholipid liposomes by nisin and the sensitivity at increased concentration of antibiotic of organisms lacking murein in their cell walls provide further evidence for the cytoplasmic membrane as a target. We therefore assume that the antimicrobial effect of nisin is caused by its interaction with phospholipid components of the cytoplasmic membrane followed by an interference with the membrane function. The sensitivity against nisin is increased in organisms with murein in their cell walls because the inhibition of this polymer causes an additional, inhibitory effect synergistic to the disturbance of the membrane function.