The distribution of Candida spp. isolated from blood cultures of Lampang hospital, Thailand included C. albicans, C. tropicalis, C. parapsilosis, C. glabrata and C. guilliermondii, with the percentage of 44.1, 35.7, 9.5, 7.1 and 3.6, respectively.
All clinical isolates of C. albicans were still susceptible to fluconazole, whereas some non-albicans Candida (NAC) exhibited the resistance to fluconazole. However, both C. albicans and NAC isolates exhibited susceptibility to amphotericin B.
Virulence factor detection revealed that C. albicans predominantly had phospholipase, proteinase and esterase activity. C. tropicalis had a predominance of esterase, while C. glabrata and C. guilliermondii had no phospholipase and proteinase activity. Biofilm-forming ability, NAC produced a biofilm at a higher rate than C. albicans.
Candidemia is one of the most common fungal nosocomial infections worldwide. It causes high mortality and morbidity rate with significant hospital costs due to increased length of hospital stay and costs for anti-fungal treatment. This study aims to investigate anti-fungal drug susceptibility, enzymatic activity and biofilm formation of the Candida spp. isolated from blood cultures. In 2016, a total of 84 clinical Candida isolates were analyzed for minimum inhibitory concentration (MIC) against fluconazole and amphotericin B by agar diffusion E-test (E-strips). Three enzymatic activity tests for phospholipase, proteinase and esterase were performed by using egg yolk agar, bovine serum albumin medium and Tween 80 opacity medium, respectively. Biofilm formation was determined by crystal violet staining. To describing the various Candida distributions cultured, C. albicans was the most frequent species (n=37, 44.1%), followed by C. tropicalis (n=30, 35.7%), C. parapsilosis (n=8, 9.5%), C. glabrata (n=6, 7.1%) and C. guilliermondii (n=3, 3.6%). Regarding anti-fungal drug susceptibility, C. albicans was susceptible to fluconazole (100%). In addition, all clinical Candida isolates were fully susceptible to amphotericin B (100%). The predominant enzyme activity of C. albicans included medium to high levels of phospholipase, proteinase and esterase activities. C. tropicalis displayed esterase activity, while C. glabrata and C. guilliermondii had no phospholipase and proteinase activity. Non-albicans Candida (NAC) i.e. C. tropicalis formed a biofilm at a higher rate than C. albicans. This study revealed the production of virulent factors in Candida strains from candidemia patients.Le texte complet de cet article est disponible en PDF.
Keywords : Candida albicans, Non-albicans Candida, Biofilm, Virulence factors