Relationship between antibacterial activity of chitosan and surface characteristics of cell wall.
OBJECTIVE
Five representative waterborne pathogens were used to illustrate the relationship between chitosan's antibacterial activity and the surface characteristics of the bacterial cell wall.


METHODS
Chitosan was prepared with averaged 75% or 95% deacetylated degree to examine its antibacterial activity against waterborne pathogens. Fresh microbial inoculants for the antibacterial assessment were prepared on nutrient agar at 37 degrees for 24 h. The evaluation items of antibacterial mechanism included hydrophilicity and negative charge analysis of cell surface, and adsorptive characteristics of chitosan to bacterial cell. All the experiments were applied in triplicate tests at least.


RESULTS
Although cell wall hydrophilicity was similar among Gram-negative bacteria, the distribution of negative charge on their cell surfaces was quite different. More negatively charged cell surfaces had a greater interaction with chitosan, a phenomenon further confirmed by transmission electron micrography (TEM).


CONCLUSIONS
Results showed the hydrophilicity in Gram-negative bacteria was much higher than in Gram-positive ones. The correlation coefficient 0.988 between the amount of absorbed chitosan and its inhibition efficiency indicated a close relationship.
Chung
Ying-chien
YC
Department of Industrial Engineering and Management, China Institute of Technology, Taipei 245, China.
Su
Ya-ping
YP
Chen
Chiing-chang
CC
Jia
Guang
G
Wang
Huey-lan
HL
Wu
J C Gaston
JC
Lin
Jaung-geng
JG
D000327:Adsorption; D000900:Anti-Bacterial Agents / Q000378:metabolism / Q000494:pharmacology*; D002473:Cell Wall / Q000737:chemistry / Q000502:physiology; D002686:Chitin / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology*; D048271:Chitosan; D004594:Electrophysiology; D013293:Enterococcus faecalis / Q000502:physiology; D004926:Escherichia coli / Q000502:physiology; D006090:Gram-Negative Bacteria / Q000502:physiology*; D006094:Gram-Positive Bacteria / Q000502:physiology*; D011550:Pseudomonas aeruginosa / Q000502:physiology; D012486:Salmonella typhimurium / Q000502:physiology; D013211:Staphylococcus aureus / Q000502:physiology; D013499:Surface Properties / Q000187:drug effects*
D000900:Anti-Bacterial Agents; D002686:Chitin; D048271:Chitosan