Evaluation of the Broad-Range PCR/ESI-MS Technology in Blood Specimens for the Molecular Diagnosis of Bloodstream Infections

PLoS One. 2015 Oct 16;10(10):e0140865. doi: 10.1371/journal.pone.0140865. eCollection 2015.

Abstract

Background: Rapid identification of the etiological agent in bloodstream infections is of vital importance for the early administration of the most appropriate antibiotic therapy. Molecular methods may offer an advantage to current culture-based microbiological diagnosis. The goal of this study was to evaluate the performance of IRIDICA, a platform based on universal genetic amplification followed by mass spectrometry (PCR/ESI-MS) for the molecular diagnosis of sepsis-related pathogens directly from the patient's blood.

Methods: A total of 410 whole blood specimens from patients admitted to Emergency Room (ER) and Intensive Care Unit (ICU) with clinical suspicion of sepsis were tested with the IRIDICA BAC BSI Assay (broad identification of bacteria and Candida spp.). Microorganisms grown in culture and detected by IRIDICA were compared considering blood culture as gold standard. When discrepancies were found, clinical records and results from other cultures were taken into consideration (clinical infection criterion).

Results: The overall positive and negative agreement of IRIDICA with blood culture in the analysis by specimen was 74.8% and 78.6%, respectively, rising to 76.9% and 87.2% respectively, when compared with the clinical infection criterion. Interestingly, IRIDICA detected 41 clinically significant microorganisms missed by culture, most of them from patients under antimicrobial treatment. Of special interest were the detections of one Mycoplasma hominis and two Mycobacterium simiae in immunocompromised patients. When ICU patients were analyzed separately, sensitivity, specificity, positive and negative predictive values compared with blood culture were 83.3%, 78.6%, 33.9% and 97.3% respectively, and 90.5%, 87.2%, 64.4% and 97.3% respectively, in comparison with the clinical infection criterion.

Conclusions: IRIDICA is a promising technology that offers an early and reliable identification of a wide variety of pathogens directly from the patient's blood within 6h, which brings the opportunity to improve management of septic patients, especially for those critically ill admitted to the ICU.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Anti-Bacterial Agents / pharmacology
  • Blood / microbiology*
  • Drug Resistance, Bacterial / genetics
  • Emergency Service, Hospital
  • Female
  • Humans
  • Intensive Care Units
  • Male
  • Middle Aged
  • Molecular Diagnostic Techniques / methods*
  • Polymerase Chain Reaction / methods*
  • Sepsis / blood*
  • Sepsis / diagnosis*
  • Sepsis / microbiology
  • Spectrometry, Mass, Electrospray Ionization / methods*
  • Young Adult

Substances

  • Anti-Bacterial Agents

Grants and funding

EM holds a Miguel Servet position for researchers in the Spanish National Health System (MS09/00044, Instituto de Salud Carlos III, Ministerio de Economía y Competitividad). This work was partially funded by grant number PTA2011-5619-T (“Personal Técnico de Apoyo”) from “Ministerio de Ciencia e Innovación” (MICINN), “Plan Nacional de Investigación científica, Desarrollo e Innovación Tecnológica (I+D+I)” and the “Sociedad Española de Enfermedades Infecciosas y de Microbiología Clínica” (SEIMC) (EJL). All reagents and materials necessary for IRIDICA testing were supplied by Ibis Biosciences. This institution had no role in study design, decision to publish, or preparation of the manuscript.