M-1721. Use of PCR on the Combination of Serum (S) and Whole Blood (WB) Specimens for the Earlier Diagnosis of Invasive Aspergillosis (IA) in Haematology Patients
Session: Slide Session: From the Clinical Mycology Laboratory
Sunday, October 26, 2008: 12:00 AM
Room: Room 207
Background: Current Aspergillus detection methods are based upon the isolation of Aspergillus DNA from fungal cells in tissue (including white blood cells) or as unbound Aspergillus DNA in serum. We hypothesize that the combined use of two extraction methods to include all forms of circulating Aspergillus DNA as a PCR template will allow for the earlier diagnosis of IA. Methods: A total of 102 patients at high risk for IA were screened by PCR twice weekly and 16 patients with proven (5) or probable (11) IA were identified. For these 16 patients DNA was extracted from 365 serum (S) and 365 whole blood (WB) specimens. All serum only (SO), whole blood only (WBO) and the combination of (S+WB) extracts were tested using a nested PCR assay. Additionally, the 365 (S) specimens were tested by galactomannan (GM) ELISA. Results: Positive PCR results occurred with (S +WB) a median of 12 days before (WBO) and a median of 7 days before (SO) in 8 of 16 and 1of 16 patients with proven or probable IA respectively. In 6 of the 9 patients in whom (S+WB) was the first to be positive by PCR a concomitant increase in GM-ELISA titres was detected. Two patients who were neutropenic and also had proven IA of the sinuses were PCR positive with (SO) before (S+WB) and (WBO) became PCR positive. Conclusions: Combining Aspergillus DNA extracted from (S) and (WB) appears to make an earlier diagnosis of IA. This may be due to the ability to detect lower levels of Aspergillus DNA. The combination of (S) and (WB) specimens as a PCR template may be of use in detecting IA in patients on mould-active prophylaxis. GM ELISA results may be useful in the interpretation of (S+WB) PCR results to confirm the diagnosis of IA. Factors such as site of IA and neutropenia may influence the release of biomarkers and the choice of specimen used to diagnose IA.
A Chan1, Alison Campbell1, C Morrissey2, Geetha Kularatne1, Monica Slavin, MBBS, MD3, Sarah Kidd, MD, MPH4 and  C. O. Morrissey,
Gilead Role(s): Grant Investigator, Speaker's Bureau, Received: Research Grant, Speaker Honorarium.
Pfizer Role(s): Grant Investigator, Scientific Advisor (Review Panel or Advisory Committee), Speaker's Bureau, Received: Research Grant, Speaker Honorarium, Consulting Fee.
Schering Plough Role(s): Grant Investigator, Scientific Advisor (Review Panel or Advisory Committee), Speaker's Bureau, Received: Research Grant, Speaker Honorarium, Consulting Fee.
Merck Sharp and Dohme Role(s): Grant Investigator, Scientific Advisor (Review Panel or Advisory Committee), Speaker's Bureau, Received: Research Grant, Speaker Honorarium, Consulting Fee., (1)Macfarlane Burnet Institute, (2)Alfred Hospital, Melbourne, Australia, (3)Peter MacCallum Cancer Ctr., Melbourne, Australia, (4)Monash University

Dr Leon Worth is a PhD scholar, training in the field of nosocomial infections in the immunocomromised. Having completed medical training at the University of Melbourne, he completed training as a fellow of the Australasian Society of Physisicans, based primarily at the Royal Melbourne Hospital. In recent years, he has continued sub-specialist training at the Peter MacCallum Cancer Centre, mostly among patients with haematologic malignancy or solid tumours. During this time, his published works have included: risk stratification and prevention PCP pneumonia, CMV infection in patients with haematologic disorders, and risks of infection in patients receiving monoclonal antibody therapy.

Sarah Kidd, M.D., M.P.H.
Dr. Kidd is a graduate of Amherst College and the University of Washington School of Medicine. She did her residency training in pediatrics at Children's Hospital in Boston. Dr. Kidd also holds a Master of Public Health degree in health policy and management from the Harvard School of Public Health.
Dr. Kidd was a pediatrician at Needham Pediatrics in Needham, Massachusetts from 2002-2004. After earning her M.P.H. in 2005, she was Assistant Medical Director of the Clinical Effectiveness and System Redesign team at University HealthSystem Consortium in Oak Brook, Illinois. In this role, she assisted academic medical centers to improve clinical processes and systems in order to provide better patient care. She has subsequently served as a Pediatric AIDS Corps physician with the Baylor International Pediatric AIDS Initiative in Malawi from 2006-2007, and in Swaziland from 2007-2008. Dr. Kidd is currently an Epidemic Intelligence Service Officer at the Global Immunization Division at the Centers for Disease Control and Prevention.