RESUMO
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.
Assuntos
Técnicas Bacteriológicas/métodos , Portador Sadio/diagnóstico , Meios de Cultura/química , Infecções por Bactérias Gram-Positivas/diagnóstico , Casas de Saúde , Enterococos Resistentes à Vancomicina/isolamento & purificação , Portador Sadio/microbiologia , Compostos Cromogênicos , Enterococcus faecalis/isolamento & purificação , Enterococcus faecium/isolamento & purificação , Fezes/microbiologia , Infecções por Bactérias Gram-Positivas/microbiologia , Humanos , Estudos Prospectivos , Sensibilidade e EspecificidadeRESUMO
ChromID ESBL agar and Brilliance ESBL agar were compared for the isolation of extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae from 298 stools. These had comparable sensitivity and selectivity for the 116 positive samples. Pre-enrichment with cefpodoxime and extending incubation to 48 hours after direct plating both significantly increased sensitivity but reduced selectivity of both agars.
