Aspergillus PCR testing: results from a prospective PCR study within the AmBiLoad trial.
OBJECTIVE
Invasive fungal infection (IFI) is a major cause of morbidity and mortality in severely immunocompromised patients and is difficult to diagnose. The significance of molecular methods for diagnosis of IFI is still controversial. In a subset of patients treated within the AmBiLoad Trial, samples were investigated prospectively by a nested Aspergillus PCR assay to re-evaluate the significance of PCR in this setting.


METHODS
In the randomized, prospective multicenter AmBiLoad trial, patients with proven or probable IFI were randomized to receive liposomal amphotericin B (L-AMB) 3 or 10 mg/kg QD for 14 d followed by L-AMB 3 mg/kg QD. From 91 patients, 459 serial samples (98% blood samples) were investigated by a nested PCR assay for Aspergillus DNA. All samples were investigated in our laboratory with a previously described nested and a quantitative PCR assay. As required by the study protocol, serial Aspergillus antigen galactomannan was performed. IFI was defined according to modified EORTC/MSG 2002 criteria as applied in the AmBiLoad trial.


RESULTS
Seven and 52 patients had proven and probable IFI according to modified EORTC/MSG criteria, respectively. The median number of samples investigated per patient was 4. Seventy percent of samples were obtained during treatment with antifungal study medication. Forty-three samples gave positive PCR results. Patients with an unfavorable outcome had a significantly higher rate of positive PCR results (48% versus 21%).


CONCLUSIONS
The sensitivity of Aspergillus PCR testing is limited during antifungal therapy. The tendency for persistently positive PCR results to indicate a poor prognosis has to be confirmed in further studies.
Hummel
Margit
M
III Medizinische Klinik, Klinikum Mannheim, University of Heidelberg, Mannheim, Germany. margithummel@yahoo.de
Spiess
Birgit
B
Cornely
Oliver A
OA
Dittmer
Martin
M
Mörz
Handan
H
Buchheidt
Dieter
D
D000293:Adolescent; D000328:Adult; D000368:Aged; D000666:Amphotericin B / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D000935:Antifungal Agents / Q000494:pharmacology / Q000627:therapeutic use; D001228:Aspergillosis / Q000175:diagnosis* / Q000209:etiology; D001230:Aspergillus / Q000235:genetics*; D004271:DNA, Fungal / Q000097:blood; D006801:Humans; D016867:Immunocompromised Host; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000187:drug effects* / Q000379:methods* / Q000592:standards; D011379:Prognosis; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D055815:Young Adult
D000935:Antifungal Agents; D004271:DNA, Fungal; C068538:liposomal amphotericin B; D000666:Amphotericin B