Fungal Plus PCR Profile II (Aspergillus Nocardia Mucorales Pneumocystis jiroveci)

Aspergillus
Inhaled dormant Aspergillus spores (conidia) can germinate and cause invasive pulmonary aspergillosis, a disease with a mortality rate often exceeding 50%. Invasive pulmonary aspergillosis is seen primarily in the immunocompromised host. Standard laboratory techniques for the diagnosis of invasive pulmonary aspergillosis include direct examination, lung tissue histology and culture of respiratory secretions. Under the best of circumstances, bronchoalveolar lavage (BAL) fluid analysis yields a diagnosis by culture and direct exam in only approximately 50% of cases. However, some centers have shown that the rate of diagnosis is substantially lower using these techniques.

The Aspergillus PCR panel is comprised of 3 real-time PCR assays: a Pan-Aspergillus assay that detects all Aspergillus species, an A. fumigatus assay that detects the most common Aspergillus species, and an A. terreus assay that detects a clinically important Aspergillus species that is resistant to Amphotericin B. When used in conjunction with other diagnostic procedures, such as microbiological culture, Aspergillus Galactomannan EIA, Fungitell® ß-D Glucan, histological examination of biopsy specimens, and radiographic evidence, the Aspergillus PCR panel can be useful in the diagnosis of invasive pulmonary aspergillosis.

Mucorales
Real-time PCR detection of Mucorales (also referred to as Zygomycetes) DNA in BAL and tissue samples may aid in diagnosis of invasive fungal infection (IFI) in high risk populations. High risk patients include those with neutropenia, solid organ transplant, hematopoietic stem cell transplant, cancer, diabetes and skin trauma. Difficult to differentiate from other filamentous fungi, mucormycosis has been found to have mortality rates in excess of 50%, depending on patient population and presentation. Further, Mucorales demonstrates limited susceptibility to a variety of antifungal therapies including Voriconazole. Early diagnosis of Mucorales has been associated with improved patient outcomes.

The use of Mucorales PCR in BAL has shown superior sensitivity over culture samples from animal models of infection and various publications indicate performance in human specimens (e.g. 100% sensitivity in biopsy tissue, 100% sensitivity established in fresh tissue samples that were culture negative, and 100% specificity in control tissue samples). The number of published studies utilizing BAL (15 studies) and biopsy (>1300) are significantly higher than any other specimen type, the next most often cited being upper respiratory specimens (n=3).

Nocardia
Standard laboratory techniques for the diagnosis of nocardiosis include culture and anti-microbial sensitivity testing for species with clinical significance, as many of the organisms are resistant to antibiotics. Nocardiosis diagnosis is often overlooked due to the length of time the isolates take to grow. Identification of Nocardia species by PCR will allow for a more rapid turnaround time enabling physicians to know to treat specifically for Nocardia rather than another bacteria.

Pneumocystis jiroveci
Pneumocystis jiroveci (formerly known as Pneumocystis carinii) pneumonia is a major cause of illness and death in individuals with impaired immune systems. Pneumocystis almost always affects the lungs, causing a form of pneumonia referred to as PCP. The organism that causes PCP has been renamed Pneumocystis jiroveci to reflect its new classification as a fungus. Quantitative DNA PCR is useful to detect the organism, track the course of infection, and monitor response to treatment.

Extraction of pathogen DNA from specimen followed by amplification and detection using real-time, quantitative PCR. An internal control is added to ensure the extraction was performed correctly and the PCR reaction was not inhibited. This test has not been cleared or approved for diagnostic use by the U.S. Food and Drug Administration.

See individual assays.