Investigation on interaction between Streptococcus sanguis and Porphyromonas gingivalis in specific pathogen-free rats.
OBJECTIVE
To examine whether endogenous Streptococcus can prevent or reduce the colonization of the virulent Porphyromonas gingivalis strain.


METHODS
Successful implantation of the endogenous strain of S. sanguis and P. gingivalis 381 within 14 days was demonstrated in the study rats following administration of doxycycline for 7 days. Thirty specific pathogen-free (SPF) rats were divided into 6 groups. After administration of doxycycline for 7 days, groups A and B were inoculated orally once a day for 5 days with P. gingivalis. Group C and E were inoculated orally once a day for 5 days with S. sanguis. Then, group A was inoculated for 5 days with S. sanguis, and rats in group C and D were inoculated for 5 days with P. gingivalis. Group F served as a negative control. After inoculation, the levels of S. sanguis and P. gingivalis in the mouths of the rats were determined at 12 hours, 24 hours, 36 hours, 7 days, and 14 days.


RESULTS
Both precolonization of S. sanguis and superinfection with S. sanguis reduced the level of P. gingivalis in experimental rats. However, the reduction was maintained for only 24 to 36 hours. The level of S. sanguis remained stable during the 14-days observation period.


CONCLUSIONS
S. sanguis to function as the effector strain, the successful implantation of S. sanguis and the antagonistic action efficiently produced in vivo by S. sanguis is required.
Zhang
J C
JC
Department of Periodontology, College of Stomatology, West China University of Medical Sciences, Chengdu, Sichuan 610041, China. zjcwcums#public.sc.cninfo.net
Zhou
C
C
Wu
B
B
Zhang
Y H
YH
D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D000898:Antibiosis; D015169:Colony Count, Microbial; D003773:Dental Plaque / Q000382:microbiology; D004318:Doxycycline / Q000008:administration & dosage; D005500:Follow-Up Studies; D005881:Gingiva / Q000382:microbiology; D009055:Mouth / Q000382:microbiology; D016966:Porphyromonas gingivalis / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D013047:Specific Pathogen-Free Organisms; D013223:Statistics as Topic; D013298:Streptococcus sanguis / Q000502:physiology*; D013997:Time Factors; D014774:Virulence
D000900:Anti-Bacterial Agents; D004318:Doxycycline