Clinical evaluation of a polymerase chain reaction assay to detect Aspergillus species in bronchoalveolar lavage samples of neutropenic patients

Abstract

Summary. The increasing incidence of invasive aspergillosis, a life-threatening infection in immunocompromised patients, emphasizes the need to improve the currently limited diagnostic tools. Using a recently developed two-step polymerase chain reaction (PCR) assay to detect 10 fg of Aspergillus DNA, corresponding to 1-5 colony-forming units (CFU)/ml of spiked samples in vitro, we prospectively examined 197 bronchoalveolar lavage (BAL) samples from 176 subjects, including 141 neutropenic, febrile patients with lung infiltrates, at risk for invasive fungal disease. Underlying diseases of these patients were haematological malignancies; 93 patients suffered from acute leukaemias. Thirty-one of these immunocompromised patients (17AE6%) were PCR positive, correlating with positive BAL culture, positive histology from lung surgery or from autopsy, positive computerized tomography scans or positive galactomannan enzyme-linked immunosorbent assay. Six patients (4AE3%) of this group had positive PCR results without any correlation to clinical or other diagnostic data, probably owing to contamination of the samples by ubiquitous Aspergillus spores. The samples of two patients (1AE4%) with a subsequent histologically proven mould infection were PCR negative. All 102 immunocompromised patients (72AE3%) with a negative PCR showed no evidence of invasive fungal disease. From 35 patients without immunodeficiency, four (11AE4%) showed positive results, without evidence of invasive or non-invasive pulmonary aspergillosis. In this haematological population, the sensitivity and specificity values of the test reached 93AE9% and 94AE4%, the positive predictive value 83AE8%, the negative predictive value 98AE1%. Our data support the considerable clinical value of this PCR assay for confirming and improving diagnosis of pulmonary aspergillosis in high-risk patients.

Galactomannan detection in computerized tomography‐based broncho‐alveolar lavage fluid and serum in haematological patients at risk for invasive pulmonary aspergillosis

“…A number of studies have reported the use of polymerase chain reaction (PCR) in BAL fluid for the diagnosis of IPA (Verweij et al, 1995a;Hayette et al, 2001;Buchheidt et al, 2002;Raad et al, 2002). However, the PPV of this test for diagnosing IPA may be compromised by the fact that it does not distinguish between infection and colonization (Hayette et al, 2001;Raad et al, 2002).…”

Invasive pulmonary aspergillosis in patients with chronic obstructive pulmonary disease

“…Although PCR on BAL fluid demonstrated poor specificity and standardisation, with 23% false-positive results [125,126], other studies demonstrated a higher sensitivity and specificity, up to 100 and 100%, respectively [127][128][129][130][131][132][133]. Furthermore, PCR may be too sensitive, so that the difference between colonisation and infection can often be difficult to establish [134].…”

Semiquantitative Detection by Real-Time PCR ofAspergillus fumigatusin Bronchoalveolar Lavage Fluids and Tissue Biopsy Specimens from Patients with Invasive Aspergillosis

“…Target sequences, either panfungal ribosomal DNA (rDNA) (8,11,12,17,19,22) or Aspergillus-specific mitochondrial DNA (mtDNA) (2,3,6,15,33) or rDNA sequences (4,5,16,25,29) have been amplified from BAL fluids (3-5, 25, 29, 33), serum (2,6), or whole blood (5,8,11,16,17,19,22,29). Detection of circulating Aspergillus DNA has shown high sensitivity but poor specificity in the screening of high-risk patients for the development of invasive disease (11).…”