Serum Is More Suitable than Whole Blood for Diagnosis of Systemic Candidiasis by Nested PCR

AUTOR(ES)

Bougnoux, M.-E.

FONTE

American Society for Microbiology

RESUMO

PCR assays for the diagnosis of systemic candidiasis can be performed either on serum or on whole blood, but results obtained with the two kinds of samples have never been formally compared. Thus we designed a nested PCR assay in which five specific inner pairs of primers were used to amplify specific targets on the rRNA genes of Candida albicans, C. tropicalis, C. parapsilosis, C. krusei, and C. glabrata. In vitro, the lower limit of detection of each nested PCR assay was 1 fg of purified DNA from the corresponding Candida species. In rabbits with candidemia of 120 minutes’ duration following intravenous (i.v.) injection of 108 CFU of C. albicans, the sensitivities of the PCR in serum and whole blood were not significantly different (93 versus 86%). In other rabbits, injected with only 105 CFU of C. albicans, detection of candidemia by culture was possible for only 1 min, whereas DNA could be detected by PCR in whole blood and in serum for 15 and 150 min, respectively. PCR was more often positive in serum than in whole blood in 40 culture-negative samples (27 versus 7%; P < 0.05%). Lastly, experiments with rabbits injected i.v. with 20 or 200 μg of purified C. albicans DNA showed that PCRs were positive in serum from 30 to at least 120 min after injection, suggesting that the clearance of free DNA is slow. These results suggest that serum is the sample of choice, which should be used preferentially over whole blood for the diagnosis of systemic candidiasis by PCR.

Documentos Relacionados

• Diagnosis of systemic candidiasis by latex agglutination for serum antigen.
• Diagnosis of Bartonella Endocarditis by a Real-Time Nested PCR Assay Using Serum
• Simple and Rapid Detection of Candida albicans DNA in Serum by PCR for Diagnosis of Invasive Candidiasis
• Improved detection of Candida albicans by PCR in blood of neutropenic mice with systemic candidiasis.
• Serum Is the Preferred Clinical Specimen for Diagnosis of Human Brucellosis by PCR