Significant discrepancy between real-time PCR identification and hospital identification of C. albicans from Lebanese patients.
BACKGROUND
The fungus C. albicans is among the leading agents causing death in immunocompromised patients. Most hospitals rely on conventional morphological techniques such as the germ-tube assay and the API system for correct identification. This technique is subjective and hence error prone. Recently, more and more molecular techniques for correct identification have been developed. The latest is the LightCycler real-time PCR technique coupled with melting curve analysis.


METHODS
One hundred hospital isolates presumed to be C. albicans from four major Lebanese hospitals were tested using the real-time PCR technique. The results were compared with a germ-tube test. Furthermore, all real-time PCR-positive samples were replica plated on growth media at 30 degrees C and 45 degrees C to differentiate between C. albicans and C. dubliniensis. Finally, all PCR-negative samples were identified using the API 20C AUX yeast identification system.


RESULTS
Twenty-four hospital isolates were non-albicans by PCR (p<0.001). Of these samples, 17 were germ tube positive (p<0.001). A further 6 samples showed positive identification by PCR, but were germ tube negative (p=0.015). Three of the 24 C. albicans-negative isolates were misidentified by the API 20C AUX. None of the C. albicans real-time PCR-positive samples failed to grow at 45 degrees C, the C. dubliniensis non-permissive temperature.


CONCLUSIONS
Considering the impact of false identification on the general public health through the use of wrong antifungal drug treatment and the emergence of novel drug-resistant strains, hospitals should update their classification methods using molecular techniques.
Yazbek
Suha
S
Department of Genetics, Case Western Reserve University, CL, USA.
Barada
Ghyda
G
Basma
Raida
R
Mahfouz
Jad
J
Khalaf
Roy A
RA
D000935:Antifungal Agents / Q000627:therapeutic use; D002176:Candida albicans / Q000235:genetics*; D002177:Candidiasis / Q000175:diagnosis* / Q000188:drug therapy; D025141:Drug Resistance, Fungal; D006761:Hospitals; D006801:Humans; D007861:Lebanon; D016533:Mycological Typing Techniques; D016133:Polymerase Chain Reaction / Q000379:methods*
D000935:Antifungal Agents