Antimicrobial effect of alexidine and chlorhexidine against Enterococcus faecalis infection.

Int J Oral Sci. 2013 Mar;5(1):26-31.

Kim HS, Woo Chang S, Baek SH, Han SH, Lee Y, Zhu Q, Kum KY.

Department of Conservative Dentistry, Dental Research Institute and BK21 Program, Seoul National University Dental Hospital, Seoul National University School of Dentistry, Seoul, Korea.


Abstract

A previous study demonstrated that alexidine has greater affinity for the major virulence factors of bacteria than chlorhexidine. The aim of this study was to compare the antimicrobial activity of 1% alexidine with that of 2% chlorhexidine using Enterococcus faecalis-infected dentin blocks. Sixty bovine dentin blocks were prepared and randomly divided into six groups of 10 each. E. faecalis was inoculated on 60 dentin blocks using the Luppens apparatus for 24 h and then the dentin blocks were soaked in 2% chlorhexidine or 1% alexidine solutions for 5 and 10 min, respectively. Sterile saline was used as a control. The antimicrobial efficacy was assessed by counting the number of bacteria adhering to the dentin surface and observing the degradation of bacterial shape or membrane rupture under a scanning electron microscope. Significantly fewer bacteria were observed in the 2% chlorhexidine- or 1% alexidine-soaked groups than in the control group (P<0.05). However, there was no significant difference in the number of bacteria adhering to the dentinal surface between the two experimental groups or between the two soaking time groups (P>0.05). Ruptured or antiseptic-attached bacteria were more frequently observed in the 10-min-soaked chlorhexidine and alexidine groups than in the 5-min-soaked chlorhexidine and alexidine groups. In conclusion, 10-min soaking with 1% alexidine or 2% chlorhexidine can be effective against E. faecalis infection.

PMID: 23492900

 

Additional pictures:

Figure 1p

Figure 1. Luppens apparatus. The apparatus consisted of a vessel containing media, a pump, a culture container and a vessel with waste, all connected by silicone tubing.

 

Figure 2p

Figure 2. Scanning electron micrographs of E. faecalis-infected dentin blocks treated with saline show a large number of adhering bacteria (A, 1,500x) with intact bacterial membranes (B, 20,000x). The group treated with 2% CHX shows reduced numbers of adhering bacteria (C, 1,500x) and many lysed E. faecalis (D, 10,000x, white arrow). The group treated with ALX also shows fewer adhering bacteria (E, 1,500x) with damaged membranes (F, 10,000x, white arrow).

 

Figure 3p

Figure 3. Scanning electron micrographs of E. faecalis-infected dentin blocks treated with saline for 10 minutes show many adhering E. faecalis (A, 1,500x) with normal shape (B, 20,000x). The group soaked with 2% CHX shows fewer adhering bacteria (C, 1,500x) and CHX particles attached to bacterial membranes (D, 20,000x, white arrow). The group treated with 1% ALX also shows fewer adhering bacteria with abnormal shape (E, 1,500x) and ALX particles attached to bacterial membranes (F, 20,000x, white arrow).

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