Molecular screening of virulence genes in high-level gentamicin-resistant Enterococcus faecalis and Enterococcus faecium isolated from clinical specimens in Northwest Iran.
OBJECTIVE
The present study screened clinical isolates of Enterococcus faecalis and Enterococcus faecium to determine the prevalence of high-level gentamicin-resistant enterococci and the potential virulence genes among them.


METHODS
Clinical enterococcal isolates were obtained from three university teaching hospitals in Northwest Iran. Isolated enterococci were identified phenotypically followed by antibiotic susceptibility testing. Multiplex PCR was performed for the detection of genus, species-specific targets, gentamicin resistance, and potential virulence genes.


RESULTS
Of 220 enterococcal isolates, 133 (60.45%) isolates were identified as high-level gentamicin-resistant. Of these isolates, 79 (59.4%) and 54 (40.6%) were E. faecalis and E. faecium, respectively. All high-level gentamicin-resistant strains carried aac(6')Ie-aph(2″)Ia. Of 220 isolates, 65.9% were positive for gelE, and 55%, 53.6%, 51.8%, and 49.5% of isolates were positive for cpd, asa1, ace, and esp, respectively. Phenotypically detected β-haemolytic strains (19.54%) were found to possess cylL ls MAB.


CONCLUSIONS
The study revealed that high-level gentamicin-resistance was related to the presence of aac(6')Ie-aph(2″)Ia. Isolated enterococci harboured potential virulence determinants, which were more common among E. faecalis than among E. faecium strains.
Research Center of Infectious Diseases and Tropical Medicine, Faculty of Medicine Department of Clinical Microbiology, Tabriz University of Medical Sciences, Tabriz, Iran.
A
A
Hasani
Y
Y
Sharifi
R
R
Ghotaslou
B
B
Naghili
A
A
Hasani
M
M
Aghazadeh
M
M
Milani
A
A
Bazmani
D000123:Acetyltransferases / Q000235:genetics; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D024881:Drug Resistance, Bacterial; D013293:Enterococcus faecalis / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D016984:Enterococcus faecium / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D005798:Genes, Bacterial; D005839:Gentamicins / Q000494:pharmacology*; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology*; D006785:Hospitals, University; D006801:Humans; D007492:Iran; D008403:Mass Screening / Q000379:methods; D008826:Microbial Sensitivity Tests; D060885:Multiplex Polymerase Chain Reaction / Q000379:methods; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics*
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D005839:Gentamicins; D037521:Virulence Factors; C108453:6'-aminoglycoside acetyltransferase-2''-aminoglycoside phosphotransferase; D000123:Acetyltransferases; D017853:Phosphotransferases (Alcohol Group Acceptor)