Aims and Objectives: The present work aimed to evaluate the frequency of aminoglycoside-
modifying enzymes encoding genes in the E. faecalis and E. faecium and their antibiotic
Methods: A total of 305 different clinical samples were subjected for identification and antibiotic
susceptibility test. The high-level aminoglycoside resistance was identified by MIC and Kirby
Bauer disc diffusion method. The prevalence of aac (6')-Ie-aph (2'')-Ia, aph (3')-IIIa and ant (4')-
Ia genes was determined by multiplex- PCR. In total, 100 enterococci strains were isolated. The
prevalence of E. faecalis and E. faecium isolates was 78% and 22%, respectively.
Results: All isolates were susceptible to linezolid. So, all E. faecalis were susceptible to vancomycin
but, 36.4% of E. faecium were resistant to it. The prevalence of multiple drug resistance
strains was 100% and 67.9% of E. faecium and E. faecalis, respectively. High-level-gentamicin
and streptomycin resistant rates were as follows; 26.9% and 73.1% of E. faecalis and 77.3% and
90.1% of E. faecium.
Conclucion: The results of the current study showed a high frequency of aac (6')-Ie-aph (2'')-Ia
genes among enterococcal isolates. A high rate of resistance to antimicrobials in Enterococcus is
obviously problematic, and a novel policy is needed to decrease resistance in these microorganisms.