DNA Microarray-based Identification of Fungal Pathogens in Neutropenic Patients in Alexandria University Hospitals in a Twelve-month Interval

Background: Systemic fungal infections are increasing, and they cause severe morbidity and high mortality rates among immuno-compromised patients. Conventional laboratory methods for identifying fungal pathogens, although continuously improving, are still time consuming. Therefore, they are usually inadequate for ensuring early targeted therapy, especially for uncommon or newly identified fungal species. Molecular detection and identification using polymerase chain reaction for the amplification of fungal DNA is being applied more frequently for the early diagnosis and identification of fungal pathogens.

Materials and Methods: The current study included 31 neutropenic cancer patients who had fever, who were not responding to antibiotics and who attended the outpatient clinics or were inpatients in the Haematology Department of the Medical Research Institute hospital and Oncology Department of Alexandria Main University hospital during a 12-month period. Blood samples were collected from each patient for the diagnosis of invasive fungal infections (IFIs) by conventional blood culture and DNA microarray.

Results: Out Of the 24 neutropenic cancer patients tested by conventional blood culture, fungal growth was detected in 2 (8.3%) blood cultures (both for Candida albicans), and the blood cultures for the remaining cases were negative. Through DNA microarray, three patients (9.7%) were found to have no fungal infections, two (6.5%) with one fungal infection, six (19.4%) with infection with two fungal species and 20 (64.5%) with infection with more than two fungal species.

Conclusion: The present oligonucleotide array system allowed the rapid and reliable identification of a vast number of fungal pathogens. Advanced diagnostic methods may have led to an overall higher sensitivity of diagnosing IFI, but the actual incidence of IFI may not have changed.