title: Molecular epidemiology of vancomycin resistant enterococci in a tertiary care hospital in Saudi Arabia.
abstract: OBJECTIVE
  Vancomycin-resistant enterococci (VRE) are a major cause of nosocomial infections with high mortality and morbidity. There is limited data on the molecular characterization of VRE in Saudi Arabia. This study was carried out to investigate the premise that a shift in VRE epidemiology is occurring in our setting.
  
  
  METHODS
  Enterococcus species identification and susceptibility testing plus VRE phenotypic confirmation by vancomycin and teicoplanin E-test were carried out. Vancomycin resistance genes were detected by PCR. Strain typing was conducted using PFGE.
  
  
  RESULTS
  Among the strains of Enterococcus spp. investigated in this study, 17 (4.5%) were VRE. With the exception of one isolate from rectal swab, all others were clinical specimens with blood being the commonest source (n = 11; 64.7%), followed by urine (n = 3; 17.6%). The 17 VRE isolates were Enterococcus faecium (n/N = 13/17) and Enterococcus gallinarum (n/N = 4/17). Among E. faecium isolates, vanA(+)/vanB(+) (n/N = 8/13; 62%) exhibiting VanB phenotype were predominant. One of the five vanA(+)E. faecium isolates exhibited a VanB phenotype indicative of vanA genotype-VanB phenotype incongruence. E. gallinarum isolates exhibited a Van C phenotype although two were vanA(+)/vanC1(+). PFGE revealed a polyclonal distribution with eight pulsotypes.
  
  
  CONCLUSIONS
  These findings indicate an evolving VRE epidemiology with vanA(+)/vanB(+) isolates and vanA genotype-VanB phenotype incongruence isolates, which were previously described as colonizers, are now causing clinical infection.
authors.affiliation: Department of Pathology and Laboratory Medicine, College of Medicine, King Saud University and King Saud University Medical City, Riyadh, Saudi Arabia.
authors.forename: Ali M
authors.initials: AM
authors.lastname: Somily
authors.affiliation: Department of Pathology and Laboratory Medicine, College of Medicine, King Saud University and King Saud University Medical City, Riyadh, Saudi Arabia.
authors.forename: Maha M
authors.initials: MM
authors.lastname: Al-Mohizea
authors.affiliation: Department of Pathology and Laboratory Medicine, College of Medicine, King Saud University and King Saud University Medical City, Riyadh, Saudi Arabia.
authors.forename: Muhammed M
authors.initials: MM
authors.lastname: Absar
authors.affiliation: Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University and King Saud University Medical City, Riyadh, Saudi Arabia.
authors.forename: Amal J
authors.initials: AJ
authors.lastname: Fatani
authors.affiliation: Department of Pathology and Laboratory Medicine, College of Medicine, King Saud University and King Saud University Medical City, Riyadh, Saudi Arabia.
authors.forename: Afaaf M
authors.initials: AM
authors.lastname: Ridha
authors.affiliation: Department of Infection and Immunity, Research Center, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia; Department of Microbiology & Immunology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia; Department of Pathology and Laboratory Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.
authors.forename: Mohammed N
authors.initials: MN
authors.lastname: Al-Ahdal
authors.affiliation: Department of Infection and Immunity, Research Center, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia; Department of Microbiology & Immunology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia.
authors.forename: Abiola C
authors.initials: AC
authors.lastname: Senok
authors.affiliation: Department of Infection and Immunity, Research Center, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia; Department of Microbiology & Immunology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia; Liver Disease Research Center, King Saud University and King Saud University Medical City, Riyadh, Saudi Arabia. Electronic address: aqahtani@kfshrc.edu.sa.
authors.forename: Ahmed A
authors.initials: AA
authors.lastname: Al-Qahtani
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001083:Arabia; D001426:Bacterial Proteins / Q000235:genetics; D019729:Carbon-Oxygen Ligases / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D052978:Disk Diffusion Antimicrobial Tests; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D005798:Genes, Bacterial; D016908:Gram-Positive Bacterial Infections / Q000453:epidemiology* / Q000382:microbiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D058889:Molecular Typing; D016133:Polymerase Chain Reaction; D012529:Saudi Arabia / Q000453:epidemiology; D017334:Teicoplanin / Q000494:pharmacology; D062606:Tertiary Care Centers; D014640:Vancomycin / Q000494:pharmacology; D065507:Vancomycin-Resistant Enterococci / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D055815:Young Adult
chemical_list: D001426:Bacterial Proteins; C071437:VanA ligase, Bacteria; C079913:VanB protein, Enterococcus; D017334:Teicoplanin; D014640:Vancomycin; D019729:Carbon-Oxygen Ligases
keywords: Pulsed-field gel electrophoresis; Van genes; Vancomycin resistant enterococci; vanA genotype-VanB phenotype incongruence