Performance of Candida Real-Time Polymerase Chain Reaction, β-D-glucan Assay, and Blood Cultures in the Diagnosis of Invasive Candidiasis

Clin Infect Dis. 2012 May;54(9):1240-8. doi: 10.1093/cid/cis200. Epub 2012 Mar 19.

Abstract

Background: The sensitivity of blood cultures for diagnosing invasive candidiasis (IC) is poor.

Methods: We performed a validated Candida real-time polymerase chain reaction (PCR) and the Fungitell 1,3-β-D-glucan (BDG) assay on blood samples collected from prospectively identified patients with IC (n = 55) and hospitalized controls (n = 73). Patients with IC had candidemia (n = 17), deep-seated candidiasis (n = 33), or both (n = 5). Controls had mucosal candidiasis (n = 5), Candida colonization (n = 48), or no known Candida colonization (n = 20).

Results: PCR using plasma or sera was more sensitive than whole blood for diagnosing IC (P = .008). Plasma or sera PCR was more sensitive than BDG in diagnosing IC (80% vs 56%; P = .03), with comparable specificity (70% vs 73%; P = .31). The tests were similar in diagnosing candidemia (59% vs 68%; P = .77), but PCR was more sensitive for deep-seated candidiasis (89% vs 53%; P = .004). PCR and BDG were more sensitive than blood cultures among patients with deep-seated candidiasis (88% and 62% vs 17%; P = .0005 and .003, respectively). PCR and culture identified the same Candida species in 82% of patients. The sensitivity of blood cultures combined with PCR or BDG among patients with IC was 98% and 79%, respectively.

Conclusions: Candida PCR and, to a lesser extent, BDG testing significantly enhanced the ability of blood cultures to diagnose IC.

Publication types

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

MeSH terms

  • Candida / chemistry
  • Candida / genetics
  • Candida / isolation & purification*
  • Candidemia / blood
  • Candidemia / diagnosis
  • Candidemia / microbiology
  • Candidiasis / blood
  • Candidiasis / diagnosis
  • Candidiasis / microbiology
  • Candidiasis, Invasive / blood
  • Candidiasis, Invasive / diagnosis*
  • Candidiasis, Invasive / microbiology
  • DNA, Fungal / blood*
  • DNA, Fungal / genetics
  • Humans
  • Prospective Studies
  • Reagent Kits, Diagnostic
  • Real-Time Polymerase Chain Reaction / methods*
  • Sensitivity and Specificity
  • beta-Glucans / blood*

Substances

  • DNA, Fungal
  • Reagent Kits, Diagnostic
  • beta-1,3-D-glucan
  • beta-Glucans