In vitro differential activity of phospholipases and acid proteinases of clinical isolates of Candida

Cristina De Andrade Monteiro,Anderson França Silva,Aurean D'Eça Júnior,Fernanda Costa Rosa,Patrícia De Maria Silva Figueiredo,Sílvio Gomes Monteiro

doi:10.1590/s0037-86822011005000036

Abstract

Candida yeasts are commensals; however, if the balance of normal flora is disrupted or the immune defenses are compromised, Candida species can cause disease manifestations. Several attributes contribute to the virulence and pathogenicity of Candida, including the production of extracellular hydrolytic enzymes, particularly phospholipase and proteinase. This study aimed to investigate the in vitro activity of phospholipases and acid proteinases in clinical isolates of Candida spp. Eighty-two isolates from hospitalized patients collected from various sites of origin were analyzed. Phospholipase production was performed in egg yolk medium and the production of proteinase was verified in a medium containing bovine serum albumin. The study was performed in triplicate. Fifty-six (68.3%) of isolates tested were phospholipase positive and 16 (44.4%) were positive for proteinase activity. C. tropicalis was the species with the highest number of positive isolates for phospholipase (91.7%). Statistically significant differences were observed in relation to production of phospholipases among species(p<0,0001) and among the strains from different sites of origin (p=0.014). Regarding the production of acid protease, the isolates of C. parapsilosis tested presented a larger number of producers (69.2%). Among the species analyzed, the percentage of protease producing isolates did not differ statistically (χ2=1.9 p=0.5901 (χ2=1.9 p=0.5901). The majority of C. non-albicans and all C. albicans isolates were great producers of hydrolytic enzymes and,consequently, might be able to cause infection under favorable conditions.

Highlights

Candida yeasts are commensals; if the balance of normal flora is disrupted or the immune defenses are compromised, Candida species can cause disease manifestations
The production of aspartyl proteases and phospholipases was studied in 82 clinical isolates of C. albicans (47 strains), C. glabrata (10 strains), C. tropicalis (12 strains), C. parapsilosis (13 strains)
Among the Candida species tested for phospholipase activity, C. tropicalis was the species with the highest number of positive isolates (91.7%)

Summary

Introduction

Candida yeasts are commensals; if the balance of normal flora is disrupted or the immune defenses are compromised, Candida species can cause disease manifestations. Conclusions: The majority of C. non-albicans and all C. albicans isolates were great producers of hydrolytic enzymes and, might be able to cause infection under favorable conditions. The polyphyletic genus Candida includes species of pathogenic fungi in humans, including Candida albicans, C. glabrata, C. parapsilosis, C. tropicalis and other species. Together these species are responsible for 34% of opportunistic fungal infections and C. albicans is the most common fungal pathogen in humans. Different species of Candida are able to express different gene products to adapt and grow in a variety of extreme physiological conditions, providing infections. These gene products are important for the virulence of Candida[2,3]

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