Antifungal susceptibility pattern and biofilm-related genes expression in planktonic and biofilm cells of species complex.

Background And Purpose: complex isolates are mainly responsible for nosocomial catheter-related infection in immunocompromised patients. Biofilm formation is regarded as one of the most pertinent key virulence factors in the development of these emerging infections. The present study aimed to compare antifungal susceptibility patterns and biofilm-related genes expression ratio in planktonic and biofilm's cells of clinically complex isolates.

Materials And Methods: The current study was conducted on a number of 17 clinical complex (10 , 5 , and 2 ). The antifungal susceptibility patterns of amphotericin B, fluconazole, itraconazole, voriconazole, posaconazole, and caspofungin in planktonic and biofilm forms were closely examined using CLSI M27-A3 broth microdilution method. The expression levels of biofilm-related genes (, and ) were evaluated in planktonic and biofilm's cells using Real-time polymerase chain reaction (PCR) technique.

Results: The obtained results indicated that all complex isolates were able to produce high and moderate amounts of biofilm forms. In addition, the sessile minimum inhibitory concentrations were reported to be high for fluconazole (≥ 64 µg/ml), itraconazole, voriconazole, and posaconazole (≥ 16 µg/ml), as compared to planktonic minimum inhibitory concentrations. Moreover, a significant difference was observed between antifungal susceptibility patterns for all azole antifungal agents (). Furthermore, the overexpression was considered significant in biofilms with regard to planktonic cells in species complex ().

Conclusion: complex isolates were found susceptible to most of the tested antifungal drugs, while biofilms demonstrated a noticeable resistant to azoles. The marked discrepancy noted in antifungal susceptibility patterns among these species should be highlighted to achieve effective therapeutic treatment.