Comparison of two chromogenic media for the detection of vancomycin-resistant enterococcal carriage by nursing home residents.
We compared ChromID VRE and Brilliance VRE media for the detection of vancomycin-resistant enterococci (VRE). Using a panel of 28 enterococcal isolates, 10 vanA Enterococcus faecium and three vanA Enterococcus faecalis isolates grew as per manufacturers' instructions whilst growth of two vanC and eight vancomycin-susceptible enterococci was inhibited on both media. Important differences were noted in the selectivity and chromogenic properties of the two media for vanA Enterococcus raffinosus and vanB E. faecium. The two media were further evaluated using 295 stool samples from nursing home residents, 34 of which grew VRE (11.5%). ChromID and Brilliance had comparable sensitivity, which was increased markedly by prolonging incubation to 48 hours (from 29% to 82%, and from 41% to 85%, respectively) and by a pre-enrichment step (to 97% and 100%, respectively). Brilliance VRE agar had higher selectivity at 48 hours, and after pre-enrichment.
Department of Medicine, University of Cambridge, Cambridge, United Kingdom; Public Health England, Clinical Microbiology and Public Health Laboratory, Cambridge, United Kingdom; Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom. Electronic address: theo.gouliouris@doctors.org.uk.
Theodore
T
Gouliouris
Department of Medicine, University of Cambridge, Cambridge, United Kingdom.
Beth
B
Blane
Department of Medicine, University of Cambridge, Cambridge, United Kingdom.
Hayley J
HJ
Brodrick
Department of Medicine, University of Cambridge, Cambridge, United Kingdom.
Kathy E
KE
Raven
Department of Medicine, University of Cambridge, Cambridge, United Kingdom.
Kirsty E
KE
Ambridge
Department of Medicine, University of Cambridge, Cambridge, United Kingdom.
Angela D
AD
Kidney
Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom.
Nazreen F
NF
Hadjirin
Department of Medicine, University of Cambridge, Cambridge, United Kingdom; Public Health England, Clinical Microbiology and Public Health Laboratory, Cambridge, United Kingdom; Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom.
M Estée
ME
Török
Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand.
Direk
D
Limmathurotsakul
Department of Medicine, University of Cambridge, Cambridge, United Kingdom; Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom; Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand; London School of Hygiene & Tropical Medicine, Keppel Street, London, United Kingdom.
Sharon J
SJ
Peacock
D001431:Bacteriological Techniques / Q000379:methods*; D002353:Carrier State / Q000175:diagnosis* / Q000382:microbiology; D002863:Chromogenic Compounds; D003470:Culture Media / Q000737:chemistry*; D013293:Enterococcus faecalis / Q000302:isolation & purification; D016984:Enterococcus faecium / Q000302:isolation & purification; D005243:Feces / Q000382:microbiology; D016908:Gram-Positive Bacterial Infections / Q000175:diagnosis* / Q000382:microbiology; D006801:Humans; D009735:Nursing Homes; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D065507:Vancomycin-Resistant Enterococci / Q000302:isolation & purification*
D002863:Chromogenic Compounds; D003470:Culture Media
Detection; Enterococcus faecium; Selectivity; Sensitivity; VRE; Vancomycin-resistant enterococci