İnvazif kandidoz olgularından izole edilen Candida albicans suşlarının genotiplendirilmesi ve virülans genlerinin varlığının araştırılması

BURAK PURAL

İnvazif kandidoz olgularından izole edilen Candida albicans suşlarının genotiplendirilmesi ve virülans genlerinin varlığının araştırılması

Thesis Type: Postgraduate

Institution Of The Thesis: Istanbul University, Health Sciences Institute, Cerrahpaşa Tıp Fakültesi Bölümü, Turkey

Approval Date: 2025

Thesis Language: Turkish

Student: BURAK PURAL

Supervisor: Gonca Erköse Genç

Open Archive Collection: AVESIS Open Access Collection

Abstract:

Invasive fungal infections pose a significant global health threat, due to their high mortality rates and the rising incidence of antifungal resistance in recent years. In the pathogenesis of fungal infections, both the host's immune status and the virulence factors of the causative species play a significant role. C. albicans is the most common Candida species, both as a microbiota member and as an infectious agent. Major virulence factors include adhesion, phenotypic switching, hyphal growth, biofilm production, and the secretion of hydrolytic extracellular enzymes such as hemolysins, proteases, and phospholipases. In this study, it was aimed to determine the genotypes of a total of 50 C. albicans strains isolated from blood specimens, previously identified by routine laboratory methods, using 25S intron analysis, and to investigate, by PCR, the presence of virulence genes including ALS1 and HWP1, which are involved in biofilm formation and adhesion, PLB1, which is involved in phospholipase activity, and SAP1, SAP2, SAP4, which are involved in secreted aspartyl proteinase activity. The genotypes of C. albicans strains isolated from pediatric and adult patients were identified as genotype A in 28 isolates (56%), genotype B in 14 isolates (28%), and genotype C in eight isolates (16%). The SAP1 gene was positive in 48 (96%) and negative in two (4%); the SAP2 and SAP4 were positive in 49 (98%) and negative in one (2%); the ALS1 and HWP1 were positive in 46 (92%) and negative in four (8%); the PLB1 was positive in 47 (94%) and negative in three (6%) isolates. No statistically significant differences were detected in the distribution of virulence genes among different C. albicans genotypes. It was concluded that a better understanding of the virulence factors of various Candida species, particularly C. albicans, and the pathogenesis of the infections they cause is crucial for the development of novel diagnostic methods, infection control strategies, and antifungal agents.