title: A prospective study of two isothermal amplification assays compared with real-time PCR, CCNA and toxigenic culture for the diagnosis of Clostridium difficile infection.
abstract: BACKGROUND
  New molecular methods of detecting Clostridium difficile infection (CDI) provide the routine lab with a sensitive random access method to produce results that are available in a shorter time than traditional methods.
  
  
  METHODS
  In this prospective study a total of 989 stool specimens were tested over a period of 16 months in parallel using two isothermal amplification assays, AmpliVue® (Quidel) and Illumigene® (Meridian) and the results compared to those from toxigenic culture. In addition all specimens were tested using a cytotoxic cell neutralisation assay (CCNA) and three different Real-time PCR targeting a C. difficile-specific 16S rDNA sequence or the toxin genes tcdA, tcdB/tcdB027 or cdtB.
  
  
  RESULTS
  AmpliVue® was positive in 242 (24.5%) and Illumigene® in 228 (23.1%) specimens. 167 (16.9%) specimens were positive in toxigenic culture. Real-time-tcdA and -tcdB PCR was positive in 211 (21.3%) specimens, Real-time-cdtB PCR was positive in 101 (10.2%) specimens and C. difficile-PCR (16S rDNA) in 267 (27.0%) specimens.
  
  
  CONCLUSIONS
  The respective sensitivity, specificity, positive predictive value and negative predictive value compared to toxigenic culture were 91, 89, 62 and 98% for AmpliVue® and 91, 91, 67 and 98% for Illumigene®.
authors: Institute of Medical Microbiology and Hospital Hygiene, University Hospital, Heinrich-Heine University, Düsseldorf, Germany. martina.becker@hhu.de.
authors: Martina
authors: M
authors: Neuendorf
authors: Institute of Medical Microbiology and Hospital Hygiene, University Hospital, Heinrich-Heine University, Düsseldorf, Germany. Raquel.guadarrama@med.uni-duesseldorf.de.
authors: Raquel
authors: R
authors: Guadarrama-Gonzalez
authors: Institute of Medical Microbiology and Hospital Hygiene, University Hospital, Heinrich-Heine University, Düsseldorf, Germany. birgit.lamik@med.uni-duesseldorf.de.
authors: Birgit
authors: B
authors: Lamik
authors: Institute of Medical Microbiology and Hospital Hygiene, University Hospital, Heinrich-Heine University, Düsseldorf, Germany. colin.mackenzie@hhu.de.
authors: Colin R
authors: CR
authors: MacKenzie
mesh_terms: D001427:Bacterial Toxins / Q000235:genetics* / Q000378:metabolism; D001681:Biological Assay / Q000379:methods*; D016360:Clostridioides difficile / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity / Q000502:physiology; D003015:Clostridium Infections / Q000175:diagnosis* / Q000382:microbiology; D005243:Feces / Q000382:microbiology; D006801:Humans; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D011446:Prospective Studies; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D014774:Virulence
chemical_list: D001427:Bacterial Toxins