Oskoui M, Farrokh P. Phenotypic and genotypic characterization of vancomycin-resistant Enterococci from clinical isolates. Iran J Med Microbiol 2008; 2 (1) :15-22
URL:
http://ijmm.ir/article-1-108-en.html
1- Department of Bacteriology, Pasteur Institute of Iran, Tehran , oskoui1@yahoo.com
2- Department of Bacteriology, Pasteur Institute of Iran, Tehran
Abstract: (19108 Views)
Background and objectives: Although Enterococci are part of the normal flora of the gastrointestinal tract
in humans, they cause infections under certain circumstances. Vancomycin Resistant Enterococci (VRE)
cause serious problems resulting in limited therapeutic options in hospitalized patients. In this study we
examined the VRE isolated from clinical specimens to determine the prevalence of vanA and vanB
phenotypes.
Material and Methods: Thirty-two vancomycin resistance Enterococci isolates cultured from clinical
samples were investigated. Resistance of isolates to vancomycin, teicoplanin, tetracycline, gentamicin,
erythromycin and ciprofloxacin were determined by disk diffusion method. MIC of vancomycin for all
strains was determined using by micro-dilution method. Existence of vanA and vanB genes was checked by
PCR.
Results: Using micro-broth dilution assay, 25 and 5 isolates appeared as vanA and vanB phenotypes
respectively. All isolates were resistance to ciprofloxacin. Resistance to erythromycin, tetracycline and
gentamicin were detected in 96.87%, 81.25% and 78.12% of isolates respectively. vanA and vanB genes
were found in 25 and 6 isolates respectively. Co-existence of vanA and vanB were found in 13 isolates using
PCR.
Conclusion: Our results showed that 12 and 6 of the strains are phenotypically and genotypically vanA and
vanB respectively. Although 13 of 25 isolates (52%) showed vanA phenotype, they have both vanA and
vanB genes. With the possibility of genotypically alteration in enterococci, it seems that these isolates
acquired vanB gene through conjugation.
Type of Study:
Original Research Article |
Subject:
Antibiotic Resistance Received: 2013/11/14 | Accepted: 2013/11/14 | ePublished: 2013/11/14