Abstract
Background and aims. Enterococci are among resistant microorganisms to antibiotics and are responsible for some of
acute gingival infections. This study aimed at molecular evaluation of gentamicin-resistant enterococcus species and determining
the resistance genes.
Materials and methods. Clinical samples were cultured on BHI medium and enterococci were isolated by specific
methods and antibiograms were prepared. DNA was derived from gentamicin-resistant species by alkaline lysis method and
replicated by PCR method. Four gentamicin-resistant genes were evaluated by electrophoresis method on agarose gel.
Results. From 105 Enterococcus faecalis isolates, 36.2% and from 38 Enterococcus faecium isolates, 78.2% were resistant
to gentamicin. 60% of these species bore aac (6’)- le – aph(2”)- la gene. ph(2”)- Ib,Ic,Id genes were not seen in any of the
evaluated species.
Conclusion. In gentamicin-resistant species of E. faecalis and E. faecium, the aac (6’)- le – aph(2”)- la gene was identified
as the main cause of resistance.