Some oral microorganisms produced porphyrin and emitted red fluorescence when illuminated with blue light (specific wavelength 405 ㎚). Porphyromonas gingivalis was classified as strain of Porphryromonas by synthesizing porphyrin. The aim of this study was to evaluate effects of Porphyromonas gingivalis on red fluorescence emission of some oral microorganisms co-cultivated with Porphyromonas gingivalis in vitro.
Bacteria were grown anerobically on Tryptic soy agar supplemented with nutrients, including iron porphyrin from heme, sheep blood and vitamin K3. The fluorescence was assessed at 405 ㎚ excitation with QLF-D (Quantitative light-induce Fluorescence Digital) camera system. The digital images were analyzed by measuring red and green values grown in close proximity area. R/G values were used for comparison of the fluorescent color. The difference R/G values in culture methods were compared with Mann-Whitney test analysis (P<0.05).
Depending on type of oral bacteria, there was difference in emission of fluorescence. Streptococcus mutans, Lactobacillus casei and Actinnomyces naeslundii were emitted red fluorescence. Fusobacterium nucleatum was emitted green fluorescence. Porphyromonas gingivalis was not emitted any color of fluorescence. R/G values were increased in blue light image as compared to white light image on Tryptic soy agar blood media. Red fluorescence was confirmed at R/G value≥2.15. To confirm findings of red fluorescence from Porphyromonas gingivalis and others grown in close proximity. Streptococcus mutans and Lactobacillus casei were decreased for R/G value (P=0.002, 0.003) that grown with Porphyromonas gingivalis. Actinomyces naeslundii and Fusobacterium nucleatum were increased for R/G value (P=0.020, 0.002) that grown with Porphyromonas gingivalis. Red fluorescence was observed from Fusobacterium nucleatum and Porphyromonas gingivalis grown together.
The microbial findings indicated that red fluorescence of some oral bacteria were interacted with Porphyromonas gingivalis.