Enterococcus faecalis Shields Porphyromonas gingivalis in Dual-Species Biofilm in Oxic Condition

• Published in: Microorganisms (Basel) Vol. 10; no. 9; p. 1729
• Main Authors: Tan, Huan Chang, Cheung, Gary Shun Pan, Chang, Jeffrey Wen Wei, Zhang, Chengfei, Lee, Angeline Hui Cheng
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 27.08.2022; MDPI
• Subjects: Aerobic conditions; Anaerobic conditions; Bacteria; biofilm model; Biofilms; Cell culture; Cell viability; confocal laser scanning microscopy; Confocal microscopy; Enterococcus faecalis; Microorganisms; Oxygen; Polymerase chain reaction; Polystyrene; Polystyrene resins; Porphyromonas gingivalis; Proteins; Scanning microscopy; Species; Thickness; Variance analysis; United States > US; Germany; aerobic conditions; cell viability; biofilm model; confocal laser scanning microscopy
• ISSN: 2076-2607; 2076-2607
• DOI: 10.3390/microorganisms10091729

Aim: To develop a reproducible biofilm model consisting of Enterococcus faecalis (E. faecalis) and Porphyromonas gingivalis (P. gingivalis) and to evaluate the interaction between the two bacterial species. Methodology: E. faecalis and P. gingivalis were grown in mono-culture, sequential, and co-culture models for 96 h in a 96-well polystyrene microtiter plate under both aerobic and anaerobic conditions separately. The viability of the two bacterial species in the biofilms was quantified by polymerase chain reaction (qPCR). Biofilm thickness and protein contents were measured using confocal laser scanning microscopy (CLSM). Two-way analysis of variance (ANOVA) was performed to analyze cell viability and biofilm thickness among different culture models cultivated under either aerobic or anaerobic conditions. The level of significance was set at p < 0.05. Results: Different culture models tested did not show any significant difference between the viable cell counts of both E. faecalis and P. gingivalis cultivated under aerobic and anaerobic conditions (p > 0.05). Biofilm was significantly thicker (p < 0.05) in the co-culture models compared to the mono-culture and sequential models. Protein contents in the biofilms were more pronounced when both bacterial species were co-cultured under aerobic conditions. Conclusions: E. faecalis appeared to shield P. gingivalis and support its continued growth in oxic (aerobic) conditions. The co-culture model of E. faecalis and P. gingivalis produced a significantly thicker biofilm irrespective of the presence or absence of oxygen, while increased protein contents were only observed in the presence of oxygen.