J Med Microbiol 56 (2007), 914-917; DOI: 10.1099/jmm.0.46829-0
© 2007 Society for General Microbiology
ISSN 1473-5644
Peptide nucleic acid fluorescence in situ hybridization for rapid detection of Klebsiella pneumoniae from positive blood cultures
Mette Søgaard1,2,
Dennis S. Hansen3,4,
Mark J. Fiandaca5,
Henrik Stender5 and
Henrik C. Schønheyder1
1 Department of Clinical Microbiology, Aalborg Hospital, Aarhus University Hospital, Postbox 365, 9100 Aalborg, Denmark
2 Department of Clinical Epidemiology, Aalborg Hospital, Aarhus University Hospital, Aarhus, Denmark
3 The International Escherichia and Klebsiella Reference Center (WHO), Statens Serum Institut, Copenhagen, Denmark
4 Department of Clinical Microbiology, Hillerød Sygehus, Denmark
5 AdvanDx Inc., Woburn, MA, USA
Correspondence
Mette Søgaard
mette.soegaard{at}rn.dk
Received 12 July 2006
Accepted 5 March 2007
This study evaluated a novel peptide nucleic acid (PNA) probe targeting a region of the 23S rRNA gene of Klebsiella pneumoniae by fluorescence in situ hybridization (FISH). Analytical performance was determined using 39 reference strains and other well-characterized strains of Klebsiella spp. and Enterobacter aerogenes. The probe was found to be specific for the K. pneumoniae complex (K. pneumoniae including Klebsiella ozaenae and Klebsiella variicola). The diagnostic accuracy was evaluated with 264 blood cultures containing Gram-negative rods. Using conventional identification as the reference, performance specifications were as follows: sensitivity 98.8 %, specificity 99.5 %, positive predictive value 98.8 % and negative predictive value 99.5 %. Discrepancies were resolved by PNA FISH retest and phenotypic tests. In conclusion, the K. pneumoniae probe provided an accurate diagnosis within 3 h and may supplement other methods for direct identification of Gram-negative bacteria.
Abbreviations: BC, blood cultures; FISH, fluorescence in situ hybridization; PNA, peptide nucleic acid.
Copyright © 2007 Society for General Microbiology.