Investigating the presence and virulence potential of <i>Enterococcus faecalis</i>, with a focus on the hyaluronidase factor, in environmental samples: Insights from a pilot study

Objectives: Enterococcus faecalis is implicated in various human diseases, including urinary tract infections, dental conditions such as periodontitis, dental caries, systemic disorders such as infective endocarditis, meningitis, intra-abdominal infections, and wound infections. The virulence genes associated with these diseases include adhesins ( ace, efaA, efaB, ebp ), biofilm-forming factors ( esp, gelE, fsr ), cytolysin ( cylA, cylB, cylM, cylL ), hyaluronidase ( hyl ), aggregation substance ( asp ), gelatinase ( gelE ), enterococcal surface protein ( esp ), among others. In a prior investigation, we observed a higher prevalence of the hyl gene in medical isolates, prompting an exploration of its occurrence in the environment. Material and Methods: 32 samples from diverse locations in and around Chennai were collected. Enterococcus spp. isolation was achieved using a partially selective medium (Ethyl Violet Azide medium). Subsequently, the isolates were identified as E. faecalis through polymerase chain reaction targeting the 16S ribosomal RNA (rRNA) gene. Positive 16S rRNA samples were further scrutinized for the presence of the hyl gene using Sequence specific oligonucleotide primers. Results: Our findings indicated an E. faecalis incidence of 41%. However, none of the isolates tested positive for the hyl virulence gene. Conclusion: This study suggests that the hyl gene may play a pivotal role in pathogenesis, as previous investigations in our laboratory involving medical isolates reported a 71% incidence of the hyl gene. In addition, our results highlight the opportunistic nature of the organism.