Background
Multidrug resistant (MDR) enterococci are important nosocomial pathogens causing serious problem in hospitalized patients. The aim of present study was to investigate the frequency of high-level aminoglycoside-resistant and vancomycin-resistant enterococci (VRE) and virulence encoding genes in enterococci isolated from hospitalized patients.
Methods
A total of 100 enterococci isolated from urine samples of hospitalized patients with symptomatic urinary tract infections were investigated for antimicrobial susceptibility, the frequency of aminoglycoside and vancomycin resistance genes (including
aac (6′)-Ie-aph (2“)-Ia, aph (3’)-IIIa, ant (4’)-Ia, aph (2”)-Ic, aph (2“)-Ib, aph (2”)-Id, ant (3″)-III, ant (6′)-Ia, vanA, vanB
and
vanC
) and virulence encoding genes (including
gelE, PAI, esp, ace, cyl, hyl
and
sprE
).
Results
Enterococcus faecalis
species was identified as predominant enterococci (69%), followed by “other”
Enterococcus
species (21%) and
E. faecium
(10%). Ninety three percent of isolates were resistant to one or more antimicrobial agents, with the most frequent resistance found against tetracycline (86%), ciprofloxacin (73%) and quinupristin-dalfopristin (53%). Gentamicin and streptomycin resistance were detected in 50 and 34% of isolates, respectively. The most prevalent aminoglycoside resistance genes were
ant (3″)-III
(78%) and
aph (3′)-IIIa
(67%). Vancomycin resistance was detected in 21% of isolates. All
E. faecium
isolates carried
vanA
gene, whereas, the
vanB
gene was not detected in
Enterococcus
species. The most frequent virulence gene was
ace
(88.6%), followed by
esp
(67.1%),
PAI
(45.5%) and
sprE
(41.7%).
Conclusion
Our study revealed the high frequency of gentamycin resistance and VRE in
E. faecium
isolates, with a high prevalence and heterogeneity of virulence and resistance genes. Due to high frequency of MDR enterococci, it seems that the appropriate surveillance and control measures are essential to prevent the emergence and transmission of these isolates in hospitals.