Chitin Oligosaccharide N,N′-Diacetylchitobiose (GlcNAc2) as Antimicrobial Coating against Listeria monocytogenes on Ready-to-Eat Shrimp (original) (raw)
In vitro Effects of Chitosan on the Survival of Listeria monocytogenes
2016
1Department of Food Hygiene and Technology, Faculty of Veterinary Medicine, Ondokuz Mayis University, Samsun-TURKEY 2Department of Food Hygiene and Technology, Faculty of Veterinary Medicine, Erciyes University, Kayseri-TURKEY 3Department of Chemistry, Faculty of Science, Anadolu University, Eskişehir-TURKEY 4Department of Food Hygiene and Technology, Faculty of Veterinary Medicine, Ankara University Ankara-TURKEY
Iranian Journal of Public Health
Background: After cellulose, chitin is one of the most important polymers in crustaceans, insects, and fungi. Chitosan is one of the most important derivatives of chitin, which has important characteristics including degradability, non-toxicity, and biocompatibility antimicrobial and antioxidant properties. Methods: Chitosan was extracted from Penaeus semisulcatus shrimp using chemical methods and the degree of its austenitization was determined using a sub-red spectrophotometer and XRD. The nanoparticles were then synthesized using the ionic gelation method and analyzed through SEM. The antimicrobial effects of nanoparticles were also evaluated using antimicrobial tests on Listeria monocytogenes and Salmonella typhi. Results: Nanoparticles have antimicrobial activity and can inhibit bacterial growth at different concentrations. Conclusion: Chitosan nanoparticles have an inhibitory effect on Listeria monocytogenes, which is a gram-positive bacterium.
Antibacterial activity of chitin, chitosan and its oligomers prepared from shrimp shell waste
Food Hydrocolloids, 2012
The antimicrobial activities of chito-oligosaccharides against four Gram-positive and seven Gramnegative bacteria were compared to chitosan and chitin with an emphasis on the effects of biopolymer molecular weight (Mv) and degree of deacetylation (DD). Chitin was isolated from shrimp (Parapenaeus longirostris) shell waste by sequential chemical treatments. Chitosan and its oligomers N-acetyl chitooligosaccharides and chito-oligosaccharides were prepared by deacetylation and chemical hydrolysis, respectively. Chitin exhibited a bacteriostatic effect on Gram-negative bacteria, Escherichia coli ATCC 25922, Vibrio cholerae, Shigella dysenteriae, and Bacteroides fragilis. Chitosan exhibited a bacteriostatic effect on all bacteria tested, except Salmonella typhimurium. The oligomers exhibited a bactericidal effect on all bacteria tested.
Effects of chitosan on experimentally induced murine Listeriosis.
The effect of chitosan treatment on experimentally induced listeriosis in mice was investigated. Fungal chitosan was obtained from the mycelia of Absidia butleri dr using hot alkali and acid treatments and comparisons were made with crustacean chitosan of shrimp origin. Fungal chitosan was not found to confer protection in Balb/c male mice against Listeria monocytogenes infection, when last administered intraperitoneally 24 hr prior to the challenge with this microbe. The treatment of fungal chitosan at 50 mg/kg body weight every other day for a week not only failed to prolong but also significantly (p<0.05) reduced the survival rate of the infected mice in which all of them died in 3 days post-infection. Analysis of blood samples taken from the mice before they succumbed to the infection revealed that the level of interferon-gamma (IFN-γ) was suppressed significantly (p<0.05). In order to show the effect of chitosan in enhancing the immune response of mice towards listerial infection, mice were immunized with inactivated L.monocytogenes. Treatment with 50 mg/kg of FC in immunized mice significantly reduced the level IFN-γ (p<0.05) in spleen cells culture supernatant. In addition to a reduction in IFN-γ levels, there was a 2.5-fold increase in the bacterial numbers in the spleen of mice receiving the same treatment. These results suggest that treatment with fungal chitosan might decrease the resistance of non-immune and immune mice against listerial infection by lowering the blood levels of IFN-γ and hence enhance bacterial growth and mortalities in mice. Although listeriosis in Balb/c mice may be aggravated by the treatment with chitosan but the potential usage of this polysaccharide and its processed forms need further studies.
Applied and Environmental Microbiology, 2010
Chitin, an insoluble polymer of N-acetyl-D-glucosamine (GlcNAc), is one of the most abundant carbohydrate polymers in marine and terrestrial environments. Chitin hydrolysis by Listeria monocytogenes depends on two chitinase-encoding genes, chiA and chiB, and the aim of this study was to investigate their regulation. Chitin induces the expression of both chitinases in late exponential growth phase, and chiA but not chiB is furthermore induced by the monomer GlcNAc. Furthermore, their expression is subjected to catabolite control. Chitinases expressed by bacterial pathogens have proven to be important not only for nutrient acquisition and environmental survival but also for infecting animals and humans. Interestingly, the central L. monocytogenes virulence gene regulator, PrfA, is required for the chitinolytic phenotype, as chitinase activity was significantly reduced in prfA mutant cells compared to its level in wild-type cells. In agreement with this, Northern blot analysis showed that the amounts of chiA and chiB transcripts upon induction by chitin were significantly lower in the prfA mutant than in the wild type. The chitinolytic activity and chiA and chiB expression were reduced in the absence of the sigB gene, indicating that B is also important for the production of chitinases. The chiA, chiB, and chiA chiB mutants were not impaired for in vitro adhesion and invasion in epithelial cell lines, but the chiA chiB double mutant showed less survival ability in a chitin-enriched medium. The regulation of chitinolytic activity in L. monocytogenes is complex, and taken together, the results indicate that the biological role of this activity may not be limited to the external environment. Listeria monocytogenes is a Gram-positive, facultative intracellular pathogen primarily causing severe infections in elderly and immunocompromised individuals. Although L. monocytogenes is widely distributed in nature and though food and feed transmission is critical for human and animal infections, the transmission pathways and natural reservoirs are not well defined (44). Recently, we observed that Listeria spp., including L. monocytogenes, encode two chitinases, ChiA (Lmo1883) and ChiB (Lmo0105), that are able to hydrolyze chitin, a highly insoluble carbohydrate polymer widely distributed in nature (28). Many bacteria from terrestrial and marine environments utilize chitin as a source of carbon and nitrogen by expressing chitinase activities, resulting in the formation of the dimer chitobiose (GlcNAc) 2 and the monomer N-acetylglucosamine (GlcNAc). The majority of bacterial chitinases belong to glycosyl hydrolase family 18, including the Listeria enzymes (50). Chitinolytic bacteria, e.g., species of the genera Bacillus, Listeria, Serratia, and Vibrio, often produce multiple chitinases, and the synergy between these is assumed to be necessary for effective chitin degradation (2, 38, 49, 57, 58). The expression of chitinases is regulated by substrates; however, there is great diversity among various chitinolytic bacteria regarding regulatory mechanisms. Substrates such as (GlcNAc) 2-6 and chitin induce chitinase gene expression, whereas GlcNAc can act
Inhibition of Listeria monocytogenes by a combination of chitosan and divergicin M35
The antimicrobial activities of the class IIa bacteriocin divergicin M35 and several types of chitosan against Listeria monocytogenes were quantified by agar diffusion, critical micro-dilution, and viable count and observed by electron microscopy. Antimicrobial activity of chitosan depended on its molecular mass (MM) and the pH. Three chitosans with MM values of 2, 20, and 100 kDa and 87.4% degree of deacetylation (DDA) were chosen for further study, based on high anti-listerial activity at pH 4.5. Electron microscopy suggested that the mechanism of anti-listerial activity also varied with the MM. Low-MM chitosan appeared to inhibit L. monocytogenes by affecting cell permeability and growth, whereas medium-and high-MM chitosan may form a barrier on the cell surface that prevents entry of nutrients. The minimum in-hibitory concentrations (MICs) of 2, 20, and 100 kDa chitosan and divergicin M35 against a divergicin-resistant strain of L. monocytogenes (LSD 535) were 2.5, 2.5, 0.625, and 0.25 mg/mL, respectively. The combination of any of these 3 chito-sans and divergicin M35 appeared to have an additive effect against L. monocytogenes, as determined by fractional inhibi-tory concentration (FIC) index. This study provides useful data for the development of chitosan films incorporating divergicin M35 for inhibiting L. monocytogenes in foods. Résumé : Les effets antimicrobiens de la divergicine M35, une bactériocine de classe IIa, et de plusieurs types de chito-sane envers Listeria monocytogenes ont e ´té quantifiés par la méthode de diffusion sur gélose, la méthode de dilution sur microplaques, le dénombrementdes cellules viables et par observation en microscopie e ´lectronique. L'activité antimicro-bienne des chitosanes dépendait de leur masse moléculaire (MM) et du pH. Trois chitosanes de 2, 20 et 100 kDa, déacéty-lés a ` 87.4 %, ont e ´té choisis dans les e ´tudes subséquentes, a ` cause de leur forte activité anti-listeria a ` pH 4.5. La microscopie e ´lectronique a suggéré que le mécanisme associé a ` l'activité anti-listeria variait aussi en fonction du MM. Le chitosane de faible MM semblait inhiber L. monocytogenes en affectant la perméabilité et la croissance cellulaires, alors que les chitosanes de MM moyenne ou e ´levée peuvent former une barrière a ` la surface de la cellule, empêchant ainsi l'entrée des nutriments. Les concentrations minimales inhibitrices (CMI) des chitosanes de 2, 20 et 100 kDa et de la diver-gicine M35 envers une souche de L. monocytogenes résistante a ` la divergicine (LSD 535) e ´taient de 2.5, 2.5, 0.625 et 0.25 mg/mL respectivement. La combinaison d'un des 3 chitosanes et de la divergicine M35 semblait avoir un effet additif en-vers L. monocytogenes, tel que déterminé par l'indice de concentration inhibitrice fractionnée « FIC index ». Cette e ´tude fournit des données utiles pour le développement de films de chitosane où la divergicine M35 est incorporée afin d'inhiber L. monocytogenes dans les aliments.
International Journal of Biological Macromolecules, 2017
Listeria monocytogenes is a foodborne bacterial pathogen that causes serious health risks. Chitosan (Ch) is a bioactive polymer that could be effectively applied for foodstuffs biopreservation. Lycium barbarum (Goji berry) is ethnopharmaceutical fruit that have diverse health protecting benefits. Chitosan was produced from A. niger and employed with L. barbarum extract (LBE) as blends for Listeria control and quality biopreservation of African catfish mince (Clarias gariepinus). Chitosan could utterly control L. monocytogenes survival in fish mince and its efficacy was strengthened with added LBE at 0.2 and 0.4%. Blending of fish mince with Ch could effectively reduce the progress of chemical spoilage parameters and this protective effect was greatly enhanced with increased addition of LBE. The sensorial assessment of treated minces indicated panelists preferences for the entire attributes of blended samples with Ch and LBE, particularly with storage prolongation. Scanning micrographs elucidated the antibacterial action of Ch against L. monocytogenes. Results recommended the application of fungal Ch/LBE composites as biopreservatives and anti-listerial agents, through their blending with catfish mince, to eliminate bacterial growth, enhance sensory and storage attributes of preserved fish.