Plate method for detection of phospholipase activity in<i>Candida albicans</i>

TLDR

Intracellular phospholipase activity has previously been detected in *Candida albicans*. The study describes a plate method for rapid detection of extracellular phospholipase activity in clinical isolates and proposes larger sampling to assess significance. The assay measures the Pz value—the ratio of colony diameter to the precipitation zone—which correlates with phosphatidylcholine hydrolysis by culture filtrates. Phospholipase activity varied widely among isolates, with 55 % of blood, 50 % of wound, and 30 % of urine isolates positive, while the Pz value remained constant for a given isolate regardless of source.

Abstract

Intracellular phospholipase activity has previously been detected in Candida albicans. A plate method is described which allows rapid detection and measurement of the extracellular activity in a number of clinical isolates. The ratio of colony diameter to diameter of the dense white zone of precipitation around phospholipase positive colonies, (Pz value), correlates with hydrolysis of [14C]phosphatidylcholine by concentrated culture filtrates of selected test isolates. A large variation in phospholipase activity is found between different isolates of C. albicans, however the Pz value is constant for any one isolate regardless of the site from which it is recovered in the patient. Fifty five % of fresh blood isolates are positive and these are also the most potent phospholipase producers. Fifty % of wound isolates and 30% of urine isolates are also positive. A larger sample group must be studied, however, before it can be determined whether these differences are highly significant.