ABSTRACT
Objective To observe the bacteriostatic effect of chitosan lactate with different relative molecular masses in vitro. Methods The MICs of the chitosans lactate with different relative molecular masses against the usual pathogens were detected,and the MBCS against two standard strains were also determined. Levofloxacin hydrochloride was used as a control drug. Results The MIC90 of chitosan lactate with 10,30,50kDa against 50 strains of gram-positive cocci and 50 strains of gram-negative bacilli were 0.5,1~4,0.5~4mg?mL-1 and 1~4,0.5~1 ,0.5~4mg?mL-1,respectively. The MIC90 of levofloxacin hydrochloride against the 50 strains of gram-positive cocci and 50 strains of gram-negative bacilli were 4～8 and 8～16?g?mL-1,respectively. ATCC 25923 strain of S.aureus and ATCC 25922 strain of E.coli could be killed by 10kDa chitosan lactate in the concentration of 4mg?mL-1. The MBCS of levofloxacin hydrochloride against ATCC25923 strain of S.aureus and ATCC 25922 strain of E.coli were 2 and 4?g?mL-1,respectively. Conclusion The 4 species of the experimental bacteria could be inhibited by the chitosan lactate with 10,30 and 50kDa Mr in vitro,but the inhibitory effect of the chitosan lactate with 10kDa Mr was stronger among them. ATCC 25923 strain of S.aureus and ATCC25923 strain of E.coli could be killed only by 10kDa chitosan lactate in vitro,not by others.