## 3 Results
### Multidrug Resistance and esp/asa1 Gene Prevalence among Enterococcus spp. Isolates
The data obtained revealed a wider distribution of the _esp_ gene among the non-invasive enterococcal isolates from urine samples (80\(\%\)) compared to invasive ones (20\(\%\)). This reaffirms the important role of _esp_ as a colonizing factor in urinary tract infections. The results are similar to those reported in Italy [33]. Concerning _asa1_, it was the most prevalent virulence gene studied (89\(\%\)), which corresponds to Iranian authors [26]. In contrast to the _esp_ gene, _asa1_ predominates in _E. faecalis_ isolates, similar to results from [PERSON] et al. and [PERSON] et al. [28, 29]. Enterococci exhibit significant antibiotic resistance, which increases the difficulty in their treatment. The high-level resistance to aminoglycosoides (gentamicin) due to aminoglycoside-modifying enzymes undermines the efficacy of the therapy used to treat serious enterococcal infections, since it eliminates synergy with cell wall active antibiotics. Among the many aminoglycoside-modifying enzymes identified, the bifunctional 6'-aminoglycoside acetyltransferase enzyme encoded by the _aac(6')/aph(2'')_ gene is the most common [34]. Several authors report that the distribution rate of the HLAR enterococci varies from 1-89\(\%\) in different regions, with a markedly a rising trend [22, 35, 36, 37, 38, 39]. Therefore, those antimicrobial agents should be used as a last resort. Ninety-eight percentage of the enterococcal isolates we studied carried the _aac(6')/aph(2'')_ gene, which confirmed the above-mentioned tendency. However, just 58\(\%\) exhibited a high-level aminoglycoside resistance with the disc diffusion method. In this regard, we can note that, since each PCR assay has inherent limitations, a negative result may not always indicate the absence of a particular gene, and a positive result, in the absence of correlated disc diffusion method results, may not always indicate the presence of an entire gene. For example, a single mutation in the gene region responsible for primer annealing may remarkably reduce the annealing efficiency and produce less or no PCR product. In addition, mutations in regions outside the PCR product that may inactivate the gene would not be found [40]. The efflux pump gene _(emeA)_ was detected in 100\(\%\) of the ciprofloxacin-resistant enterococci in our study, suggesting that the drug efflux is the main mechanism involved in the resistance of enterococci to the fluoroquinolones. However, the _emeA_ gene was harbored in 43\(\%\) of ciprofloxacin-susceptible enterococci, indicating the lack of expression of the _emeA_ gene in some isolates. Regarding ciprofloxacin-resistant enterococci, Chinese authors reported a much higher rate (86\(\%\)) compared to our results (48\(\%\)) and revealed that a lower rate of ciprofloxacin-resistant isolates possessed the _emeA_ gene, suggesting the involvement of other mechanisms in enterococcal fluoroquinolones resistance, in addition to drug efflux [16]. The resistance of enterococci to \(\beta\)-lactams is due to the production of \(\beta\)-lactamase encoded by the _TEM_ gene or modification in penicillin-binding proteins (PBPs) [41, 42]. In terms of ampicillin resistance, 100\(\%\) and 98\(\%\), respectively, of the tested clinical isolates were reported as resistant in Egypt and India [22, 38], while the percentage of ampicillin-resistant enterococci in our study was much lower (62\(\%\)). The _TEM_ gene was detected in only six of our isolates (four _E. faecalis_ and two _E. facecium_, respectively). Multidrug-resistant and, in particular, vancomycin-resistant enterococci (VRE) are serious issues that considerably reduce the treatment options of infections caused by these microorganisms [43]. A number of studies have found that VRE-caused infections are associated with higher mortality and economic burden compared to the glycopide-sensitive strains [44]. Therefore, vancomycin-resistant enterococci might be expected to be a major issue in the coming years. Variable rates of vancomycin resistance among enterococci were detected worldwide.