Dental clinic surfaces as reservoirs of biofilm-forming Staphylococcus aureus and Enterococcus spp. isolates: phenotypic and genotypic analysis.

BACKGROUND

Dental clinic surfaces may serve as reservoirs for opportunistic pathogens that can survive environmental stress, persist on abiotic surfaces, and contribute to cross-contamination. This study investigated the phenotypic biofilm-forming capacity and selected biofilm-associated virulence genes of Staphylococcus aureus and Enterococcus spp. isolated from environmental surfaces in a university dental clinic in Kütahya, Türkiye.

METHODS

A total of 196 environmental surface samples were collected from five clinical units. Biofilm-forming capacity was assessed using the crystal violet microtiter plate assay. The presence of icaA and icaD in S. aureus isolates and gelE and esp in Enterococcus spp. isolates was determined by PCR.

RESULTS

Overall, 84 S. aureus and 64 Enterococcus spp. isolates were recovered. Biofilm production was detected in 78.6% of S. aureus isolates and 98.4% of Enterococcus spp. isolates. Moderate and strong biofilm production was more frequent among Enterococcus spp. Molecular analysis identified icaD in 65.5% and icaA in 19.0% of S. aureus isolates. Among Enterococcus spp. isolates, gelE and esp were detected in 46.9% and 34.4%, respectively, while 14.1% carried both genes.

CONCLUSIONS

Dental clinic surfaces may harbor S. aureus and Enterococcus spp. isolates with substantial biofilm-forming capacity and selected virulence-associated genes. The predominance of moderate and strong biofilm production among Enterococcus spp. suggests a potential for persistence under the tested conditions. These findings support routine environmental surveillance and surface-specific cleaning and disinfection strategies, particularly for frequently contacted dental equipment.