COMPARATIVE STUDY OF PROTEINASE ACTIVITY IN CANDIDA ISOLATES

Background and Aim:Proteinases play pivotal roles in Candida albicans infectionsand they are necessary to colonize and invade host tissues.This study aims to characterize proteinase activities of the 30 clinicalCandidaalbicans and non-albicans isolates.Methods: Proteinase activity of Candida isolates was evaluated by their ability to secrete aspartyl proteinase (SAP) on a solid medium. All of the Candida isolates were cultured on bovine serum albumin (BSA) agar medium and the plates were incubated at 37° C.The diameter of the colonies and the colonies plus precipitation zone (Pz) was evaluated after 3-8 days. Each isolate was tested in triplicate, and the enzyme activity value was taken as the average of the three measurements.C.albicans ATCC 10231 strain was used as positive control.The phospholipase activity was calculated according to Price et al. All the Candida isolates were grouped according to the Pz value as following: Pz = 1, no phospholipase activity; 0.64 > Pz< 1, moderate phospholipase activity (+); Pz<0.64 high phospholipase activity (++). By this classification, a high Pz value indicates low enzymatic activity.Results:All of Candida isolates were proteinase positive. Twenty one isolates (70 %) represented strong proteinase activity and 9 isolates (30 %) had moderate activity.Conclusion:Taken together, identification of proteinase activity of clinical isolates of Candida may be helpful to use suitable antifungal drugs and prevent increased drug resistance and nosocomial infections.

کلیدواژه ها:

Candida albicans ، Proteinase activity ، Clinical isolates ، Candida non-albicans