In vivo bactericidal effect of 0.2% chlorhexidine but not 0.12% on salivary obligate anaerobes.
OBJECTIVE
To evaluate the in vivo antimicrobial activity on the salivary flora of a single mouthrinse of chlorhexidine (CHX) digluconate, analysing the influence of its concentration (0.2% versus 0.12%).


METHODS
The study group was formed of 20 adult volunteers with a good oral health status. Non-stimulated saliva samples were collected under basal conditions and at 30s and 1h after a single mouthrinse with sterile water, 0.2% or 0.12% CHX digluconate. Serial dilutions were then performed and the resulting samples were cultured on conventional culture media for aerobes/facultative anaerobes and obligate anaerobes. The number of colony forming units (CFU/ml) was then determined and the results expressed on a decimal log scale (log(10)CFU/ml).


RESULTS
A significant reduction in the total bacterial population was observed at 30s and 1h after the mouthrinse with both CHX concentrations; this antimicrobial activity was more pronounced on the obligate anaerobes. The antimicrobial activity of 0.2% CHX on the salivary flora at 30s and 1h after the mouthrinse was significantly greater than that of 0.12% CHX. Only 0.2% CHX showed bactericidal activity (differential factor> or =3 log(10)CFU/ml) against salivary obligate anaerobes.


CONCLUSIONS
The greater antimicrobial activity of 0.2% CHX confirms the influence of the concentration on its antibacterial activity. In consequence, the CHX concentration seems to be an important factor to guarantee a high antibacterial activity in those clinical situations where it is required.
Tomás
I
I
Faculty of Medicine and Dentistry, Santiago de Compostela University, Spain.
Cousido
M C
MC
Tomás
M
M
Limeres
J
J
García-Caballero
L
L
Diz
P
P
D000328:Adult; D000890:Anti-Infective Agents / Q000494:pharmacology*; D001421:Bacteria, Anaerobic / Q000187:drug effects*; D002710:Chlorhexidine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D015169:Colony Count, Microbial; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009055:Mouth / Q000382:microbiology; D009067:Mouthwashes / Q000737:chemistry / Q000494:pharmacology*; D012463:Saliva / Q000382:microbiology*; D055815:Young Adult
D000890:Anti-Infective Agents; D009067:Mouthwashes; C010882:chlorhexidine gluconate; D002710:Chlorhexidine