Comparison of genotypes, antimicrobial resistance and virulence profiles of oral and non oral Enterococcus faecalis from Brazil, Japan and the United Kingdom

Abstract

Objectives:To determine whether phenotypic and genotypic differences amongst isolates of Enterococcus faecalis relate to geographical and clinical origin. Methods: E. faecalis from primary endodontic infections in Brazilian patients (n=20), oral infections in UK patients (n=10), and non-oral infections in Japanese patients (n=9) were studied. In addition, 20 environmental vancomycin resistant Enterococcus faecalis (VRE) isolates from a UK hospital were analysed. For all isolates, polymerase chain reaction (PCR) was used to detect genes associated with antibiotic resistance and virulence, whilst randomly amplified polymorphic DNA-PCR (RAPD-PCR) was used to produce molecular profiles. Results: Gelatinase gene (gelE) was prevalent amongst isolates (77-100%) and for oral isolates, genes of aggregation substances (agg), immune evasion protein (esp), cytolysin (cylB), tetracycline resistance (tetM; tetL) and erythromycin resistance (ermB) were detected to varying extent. Japanese non-oral isolates had a similar genetic profile to oral isolates, but with higher prevalence of ermB and cylB. All VRE isolates were positive for gelE, esp, agg, vanA, ermB and tetM, 95%were positive for cylB and 17% positive for tetL. All isolates were negative for ermA, asa373 vanB, vanC1 and vanC2/3. RAPD-PCR revealed clustering of VRE isolates.Conclusions: RAPD-PCR analysis revealed extensive genetic variability among the tested isolates. Oral isolates carried antibiotic resistance genes for tetracycline and whilst they possessed genes that could contribute to pathogenicity, these were detected at lower incidence compared with non-oral and VRE isolates. RAPD-PCR proved to be a useful approach to elucidate relatedness of disparate isolates.

Presence of non-oral bacteria in the oral cavity

“…Wang et al (2011) demonstrated that the prevalence of E. faecalis in the root canal system had been correlated with its occurrence in saliva. Meanwhile, some authors suggested nosocomial transmission from environmental surfaces in dental surgeries due to the robust nature of the microorganisms (Vidana et al 2011;Lins et al 2019), while others proposed foodborne transmission (Zehnder and Guggenheim 2009). However, Vidana et al (2011) examined the genetic relationship between E. faecalis from root canals and isolates from different host sources and found that isolates from the root canals were not related to those from the typical gastrointestinal microflora, and none of these patients was recorded to have enterococci in their saliva.…”

Final Endodontic Irrigation with 2% Peracetic Acid: Antimicrobial Activity and Cytotoxicity

“…32 With regard to the evaluation of the antimicrobial action of endodontic agents, a strain of Enterococcus faecalis previously isolated from endodontic infection was used, identified by MALDI-TOF and PCR for 16S rRNA, and subjected to trypticase soy agar (TSA) having obtained the result of strain resistant to antibiotics. 33 Other authors reported a variation between 24 to 77% in the prevalence of Enterococcus faecalis in the root canals, and this bacterium could penetrate the dentinal tubules as well as the potential to be the infectious agent itself. 15,33,34 The formation of the biofilm for the study occurred for 21 days in human dentin blocks standardized in 5 mm in length, with similarity between the sample confirmed by the equivalence of the dentine volume weighing 0.2 g. Interestingly, this lifetime of 21 days, biofilm is more resistant to agents used in endodontic treatments.…”

“…33 Other authors reported a variation between 24 to 77% in the prevalence of Enterococcus faecalis in the root canals, and this bacterium could penetrate the dentinal tubules as well as the potential to be the infectious agent itself. 15,33,34 The formation of the biofilm for the study occurred for 21 days in human dentin blocks standardized in 5 mm in length, with similarity between the sample confirmed by the equivalence of the dentine volume weighing 0.2 g. Interestingly, this lifetime of 21 days, biofilm is more resistant to agents used in endodontic treatments. 35 Arias-Moliz et al 36 found a minimal biofilm eradication of Enterococcus faecalis after exposure of 1, 5 and 10 minutes in different concentrations of NaOCl and CHX; the findings were that NaOCl was capable of minimal eradication of the biofilm after a period of one minute in concentrations below 0.1%, while CHX achieved this result after five minutes at 0.2%36.…”

“…CHX demonstrated antimicrobial activity against the strain of Enterococcus faecalis and showed less cytotoxicity compared with NaOCl, which allows its use as an alternative to avoid the deleterious effects on periapical tissues. [31][32][33][34][35][36][37]39,40 Nevertheless, its antimicrobial action occurs on the cytoplasmic membranes of bacterial cells, which raises concerns about the resistance of these microorganisms. 39,40 That is the reason for NaOCl not being substituted, since its antimicrobial action occurs through unspecific destruction of the bacterial cell, which avoids the undesirable effect of microbiological resistance; with regard to the risks of damage to the periapical tissues, they can be controlled by a safe irrigation technique.…”

Vancomycin-Resistant Enterococcus: Issues in Human Health, Animal Health, Resistant Mechanisms and the Malaysian Paradox

“…It not only links epithelial cells to virulent characteristics and resistant determinants via plasmid exchange and colonization but also attaches to the network of extracellular proteins (Wagner et al, 2018). Different studies have provided evidence that E. faecalis harbors the agg gene most (Guzman Prieto et al, 2016;Lins et al, 2019;Farman et al, 2019).…”