Coexistence of <i>Candida albicans</i> and <i>Enterococcus faecalis</i> increases biofilm virulence and periapical lesions in rats
Qian Du, Shasha Yuan, Shuangyuan Zhao, Di Fu, Yifei Chen, Yuan Zhou, Yangpei Cao, Yuan Gao, Xin Xu, Xuedong Zhou, Jinzhi He
Abstract
The present study utilized an in vitro dual-species biofilm model and an in vivo rat post-treatment endodontic disease (PTED) model to investigate whether co-infection of Candida albicans and Enterococcus faecalis would aggravate periapical lesions. The results showed that co-culturing yielded a thicker and denser biofilm more tolerant to detrimental stresses compared with the mono-species biofilm, such as a starvation-alkalinity environment, mechanical shear force and bactericidal chemicals. Consistently, co-inoculation of E. faecalis and C. albicans significantly increased the extent of in vivo periapical lesions compared with mono-species infection. Specifically, coexistence of both microorganisms increased osteoclastic bone resorption and suppressed osteoblastic bone formation. The synergistic effects also up-regulated inflammatory cytokines including TNF-α and IL-6. In summary, coexistence of C. albicans and E. faecalis increased periapical lesions by enhanced biofilm virulence.