TY - JOUR
T1 - Sensitive detection of Francisella tularensis directly from whole blood by use of the GeneXpert system
AU - Banada, Padmapriya P.
AU - Deshpande, Srinidhi
AU - Chakravorty, Soumitesh
AU - Russo, Riccardo
AU - Occi, James
AU - Meister, Gabriel
AU - Jones, Kelly J.
AU - Gelhaus, Carl H.
AU - Valderas, Michelle W.
AU - Jones, Martin
AU - Connell, Nancy
AU - Alland, David
N1 - Funding Information:
This research was supported in part by the National Institute of Allergy and Infectious Disease of the National Institutes of Health under awards AI098713 (D.A.), HHSN27220100003I (Battelle Memorial Institute, Columbus, OH), and HHSN266200400095I (Lovelace Respiratory Research Institute, Albuquerque, NM).
Publisher Copyright:
Copyright © 2016 American Society for Microbiology. All Rights Reserved.
PY - 2017/1
Y1 - 2017/1
N2 - Francisella tularensis is a potential bioterrorism agent that is highly infectious at very low doses. Diagnosis of tularemia by blood culture and nucleic acidbased diagnostic tests is insufficiently sensitive. Here, we demonstrate a highly sensitive F. tularensis assay that incorporates sample processing and detection into a single cartridge suitable for point-of-care detection. The assay limit of detection (LOD) and dynamic range were determined in a filter-based cartridge run on the GeneXpert system. F. tularensis DNA in buffer or CFU of F. tularensis was spiked into human or macaque blood. To simulate detection in human disease, the assay was tested on blood drawn from macaques infected with F. tularensis Schu S4 at daily intervals. Assay detection was compared to that with a conventional quantitative PCR (qPCR) assay and blood culture. The assay LOD was 0.1 genome equivalents (GE) per reaction and 10 CFU/ml F. tularensis in both human and macaque blood. In infected macaques, the assay detected F. tularensis on days 1 to 4 postinfection in 21%, 17%, 60%, and 83% of macaques, respectively, compared to conventional qPCR positivity rates of 0%, 0%, 30%, and 100% and CFU detection of blood culture at 0%, 0%, 0%, and 10% positive, respectively. Assay specificity was 100%. The new cartridge-based assay can rapidly detect F. tularensis in bloodstream infections directly in whole blood at the early stages of infection with a sensitivity that is superior to that of other methods. The simplicity of the automated testing procedures may make this test suitable for rapid point-of-care detection.
AB - Francisella tularensis is a potential bioterrorism agent that is highly infectious at very low doses. Diagnosis of tularemia by blood culture and nucleic acidbased diagnostic tests is insufficiently sensitive. Here, we demonstrate a highly sensitive F. tularensis assay that incorporates sample processing and detection into a single cartridge suitable for point-of-care detection. The assay limit of detection (LOD) and dynamic range were determined in a filter-based cartridge run on the GeneXpert system. F. tularensis DNA in buffer or CFU of F. tularensis was spiked into human or macaque blood. To simulate detection in human disease, the assay was tested on blood drawn from macaques infected with F. tularensis Schu S4 at daily intervals. Assay detection was compared to that with a conventional quantitative PCR (qPCR) assay and blood culture. The assay LOD was 0.1 genome equivalents (GE) per reaction and 10 CFU/ml F. tularensis in both human and macaque blood. In infected macaques, the assay detected F. tularensis on days 1 to 4 postinfection in 21%, 17%, 60%, and 83% of macaques, respectively, compared to conventional qPCR positivity rates of 0%, 0%, 30%, and 100% and CFU detection of blood culture at 0%, 0%, 0%, and 10% positive, respectively. Assay specificity was 100%. The new cartridge-based assay can rapidly detect F. tularensis in bloodstream infections directly in whole blood at the early stages of infection with a sensitivity that is superior to that of other methods. The simplicity of the automated testing procedures may make this test suitable for rapid point-of-care detection.
KW - Diagnostic
KW - Francisella tularensis
KW - GeneXpert
KW - Macaque blood
KW - PCR
KW - Whole blood
UR - http://www.scopus.com/inward/record.url?scp=85008352081&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85008352081&partnerID=8YFLogxK
U2 - 10.1128/JCM.01126-16
DO - 10.1128/JCM.01126-16
M3 - Article
C2 - 27847371
AN - SCOPUS:85008352081
SN - 0095-1137
VL - 55
SP - 291
EP - 301
JO - Journal of clinical microbiology
JF - Journal of clinical microbiology
IS - 1
ER -