Enterococcus faecalis from patients with chronic periodontitis: virulence and antimicrobial resistance traits and determinants

This study investigated the presence of virulence and resistance traits, as well as their genetic determinants in subgingival Enterococcus faecalis from patients with chronic periodontitis. Twenty-four E. faecalis strains from a previously multi-locus sequence typing (MLST)-characterized strain collection were examined for virulence-associated phenotypes, antimicrobial susceptibility, and virulence- and antimicrobial-resistant determinants. Gelatinase, hemolysin, and biofilm production were detected in 50, 17, and 100% of the strains, respectively. Genes encoding adherence factors such as ace, efaA, and bopD were detected in all isolates. Other putative virulence determinants, i.e., EF3314, gelE, asa, esp, cylA, ef1841/fsrC, and asa373, were found in a portion of the strains. Different levels of resistance were observed in these strains, with two strains expressing high-level resistance to erythromycin and gentamicin. The integrase gene and accessory gene(s) of the Tn916/Tn1545 family were detected in ten strains. A direct link was shown between the presence of Tn916/Tn1545-like elements and resistance to doxycycline and/or erythromycin. The results demonstrated that virulence and antibiotic resistance determinants were prevalent in oral E. faecalis strains. It implicates that oral E. faecalis might play a role in the pathogenesis of chronic periodontitis and be a potential reservoir for the transferable elements of virulence and antimicrobial resistance.