Molecular Identification and Virulence Factors Determination in Candida Species Isolated from Egyptian Patients

Abstract

Candida-related infections are becoming a universal threat to the health of human who undergo immunosuppressive therapy or aggressive medical intervention. Objectives: The aim was to study the distribution of Candida species among winter and summer seasons and to determine the expression of their virulence factors. Methods: A total of 164 Candida isolates were collected from clinical specimens at Mansoura University Hospitals. Candida species were identified by polymerase chain reaction (PCR). Extracellular phospholipase, secretory aspartyl proteinase (SAP) and coagulase enzymes and biofilm formation were determined. SAP 9 and 10 genes were detected by PCR. Results: Non-albicans (NAC) isolates were more dominant than C. albicans isolates (P value C. tropicalis was the most prevalent (59.2%) followed by C. albicans (31.1%), then C. glabrata, C. krusie, unidentified NAC and C. kefyr in 3.7%, 2.4%, 2.4% and 1.2% respectively. Extracellular phospholipase activity was detected in 31.7% of Candida isolates. All C. albicans had phospholipase activity (100%) and one isolate of C. tropicalis was positive while other species were negative. SAPs activities were determined in 61.6% of Candida isolates and were detected in 70.1% and 62.7% among C. tropicalis and C. albicans isolates respectively. SAP9 and SAP 10 genes were detected in 27.7% and 12.9% of Candida isolates showed positive SAPs activity respectively and they were all C. albicans strains. Other species did not harbor either SAP9 or SAP10. Coagulase activity was detected in 80.4% of Candida isolates with higher activity in C. albicans (88.2%), followed by C. tropicalis (81.4%), then other NAC isolates. Biofilm formation was determined in 69.5% of Candida isolates and was more prevalent in C. tropicalis (82.5%) followed by C. albicans (19.6%), C. krusie (100%), unidentified NAC (75%), C. glabrata (33.3%) and C. kefyr (50%). Conclusion: NAC with a preponderance of C. tropicalis was the most common isolated Candida species. Biofilm production, proteinase, phospholipases and coagulase enzymes were observed in both C. albicans and NAC. SAP9 and SAP 10 genes were detected only in C. albicans strains.