viernes, 18 de octubre de 2013

Deteccion de NDM, VIM Y KPC en exudado rectal en tan solo 47 minutos

Cepheid esta probando el "Xpert MDRO Assay". No se cuando saldrá al mercado pero parece prometedor. Esperemos poder probarlo a la brevedad.

Detection of Colonization by Carbapenemase-Producing Gram- Negative Bacilli in Patients by Use of the Xpert MDRO Assay
Fred C. Tenover,a Rafael Canton,b JoAnn Kop,a Ryan Chan,a Jamie Ryan,a Fred Weir,a Patricia Ruiz-Garbajosa,b Vincent LaBombardi,c*
David H. Persinga
Cepheid, Sunnyvale, California, USAa; Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria, Madrid, Spainb; Microbiology Laboratory, Mt. Sinai Medical Center, New York, New York, USAc
Detecting colonization of patients with carbapenemase-producing bacteria can be difficult. This study compared the sensitivity and specificity of a PCR-based method (Xpert MDRO) for detecting blaKPC, blaNDM, and blaVIM carbapenem resistance genes using GeneXpert cartridges to the results of culture with and without a broth enrichment step on 328 rectal, perirectal, and stool samples. The culture method included direct inoculation of a MacConkey agar plate on which a 10-􏰀g meropenem disk was placed and plating on MacConkey agar after overnight enrichment of the sample in MacConkey broth containing 1 􏰀g/ml of meropenem. Forty-three (13.1%) samples were positive by PCR for blaKPC and 11 (3.4%) were positive for blaVIM; none were positive for blaNDM. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the PCR assay for blaKPC were 100%, 99.0%, 93.0%, and 100%, respectively, compared to broth enrichment culture and sequencing of target genes. The sensitivity, specificity, PPV, and NPV of the assay for blaVIM were 100%, 99.4%, 81.8%, and 100%, respectively. Since none of the clinical samples contained organisms with blaNDM, 66 contrived stool samples were prepared at various dilu- tions using three Klebsiella pneumoniae isolates containing blaNDM. The PCR assay showed 100% positivity at dilutions from 300 to 1,800 CFU/ml and 93.3% at 150 CFU/ml. The Xpert MDRO PCR assay required 2 min of hands-on time and 47 min to complete. Rapid identification of patients colonized with carbapenemase-producing organisms using multiplex PCR may help hospitals to improve infection control activities. 


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