Evaluation of nested and real-time PCR assays in the diagnosis of candidaemia.
Polymerase chain reaction (PCR) assays have a very low theoretical detection threshold and are therefore advocated for the diagnosis of fungaemia. However, their effectiveness in this respect remains to be assessed. This study compared real-time PCR (Can-G) and nested PCR assays with blood culture for the diagnosis of Candida spp. bloodstream infections. A total of 200 clinical blood samples obtained from 110 patients at risk for developing a systemic fungal infection, hospitalized in the University Hospital of Sfax (Tunisia), were submitted to testing by culture, nested PCR and real-time PCR. Blood culture was positive in 36 patients. When compared with culture, the Can-G assay (81% sensitivity, 96% specificity) performed better than the nested PCR assay (86% sensitivity, 54% specificity). The real-time PCR assay, which avoids both the contamination hazard with amplicons that may cause false-positive results and the use of time-consuming post-PCR steps, appears more suitable than the nested PCR assay for the laboratory diagnosis of Candida spp. bloodstream infections. In this study, real-time PCR did not enhance the diagnostic sensitivity for Candida spp. bloodstream infections compared with conventional blood culture; however, it may lead to earlier implementation of an adequately targeted antifungal treatment.
Laboratoire de Biologie Moléculaire Parasitaire et Fongique, Faculté de Médecine, University of Sfax, Sfax, Tunisia.
M
M
Khlif
C
C
Mary
H
H
Sellami
A
A
Sellami
H
H
Dumon
A
A
Ayadi
S
S
Ranque
D001769:Blood / Q000382:microbiology; D002175:Candida / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D002177:Candidiasis / Q000175:diagnosis / Q000382:microbiology; D003470:Culture Media; D004271:DNA, Fungal / Q000032:analysis / Q000302:isolation & purification; D016469:Fungemia / Q000175:diagnosis* / Q000382:microbiology; D006801:Humans; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D013045:Species Specificity
D003470:Culture Media; D004271:DNA, Fungal