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Published on: July 9, 2012
Genotyping, antimicrobial resistance and virulence factor gene profiles of vancomycin resistance Enterococcus
Shahnaz Armin1, Fatemeh Fallah1, Abdollah Karimi1
1Pediatric Infections Research Center, Mofid Children Hospital, Shahid Beheshti University of Medical Sciences, Tehran, 15468-15514, Iran.
Background:
Enterococcus spp. is the common of intestinal micro flora in humans but nowadays this gram-positive bacterium causes the variety of nosocomial infections. Resistance to antibiotic and also, presence of different virulence genes in the enterococcus spp. can change it to problematic microorganisms in the health care centers. The aim of this study was determined the genotyping, antimicrobial resistance and virulence factor gene profiles of vancomycin resistance Enterococcus faecalis isolated from blood culture.
Methods:
In this study, enterococcus isolated from BACTEC was collected and antibiotic susceptibility testing was done according to CLSI recommendation. Important virulence genes and vancomyci resistance genes were detected by PCR and molecular typing was performed by RAPD PCR assay.
Results:
Nine enterococcus collected from 194 positive BACTEC and seven out of nine were vancomycin-resistant enterococcus (VRE). vanA gene observed in all VRE and none of strains carried vanB and vanC genes. efbaA and gelE virulence factors have been detected in all strains. ace, esp, and cyl virulence factors genes harbored in two, seven and eight isolates respectively. asaI was not detected in any strains. All seven VRE isolates were related to the one specific molecular type and two different molecular types observed in the two vancomycin susceptible enterococci according to molecular epidemiology results.
Conclusion:
More prevalence of the VRE in enterococcus isolated from BACTEC is so important and on the other hand high genetic relationship in the isolated VRE can be very considerable for nosocomial infection committee in the hospital.
Insights
Vancomycin-resistant Enterococcus (VRE) is prevalent in blood cultures, with the vanA gene found in all resistant strains. High genetic similarity among VRE isolates suggests a significant risk for hospital-acquired infections.
Area of Science:
- Clinical Microbiology
- Infectious Diseases
- Molecular Epidemiology
Background:
- Enterococcus species are common gut flora but cause nosocomial infections.
- Antibiotic resistance and virulence factors make Enterococcus problematic in healthcare settings.
- This study focused on vancomycin-resistant Enterococcus faecalis from blood cultures.
Purpose of the Study:
- To determine the genotyping, antimicrobial resistance, and virulence factor gene profiles.
- To investigate vancomycin resistance mechanisms in Enterococcus faecalis.
- To assess the molecular epidemiology of isolated strains.
Main Methods:
- Antibiotic susceptibility testing performed per CLSI guidelines.
- Detection of vancomycin resistance and virulence genes using PCR.
- Molecular typing of isolates via RAPD PCR assay.
Main Results:
- Seven of nine Enterococcus isolates were vancomycin-resistant (VRE).
- All VRE isolates possessed the vanA gene; vanB and vanC were absent.
- Common virulence factors (efdA, gelE) were present in all strains; others varied.
- VRE isolates showed high genetic relatedness, indicating a common source.
Conclusions:
- The high prevalence of VRE in blood cultures is a significant concern.
- The genetic homogeneity of VRE isolates warrants attention for infection control.
- Findings are crucial for hospital nosocomial infection committees.
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