Cryptococcus laurentii Biofilms: Structure, Development and Antifungal Drug Resistance

Abstract

A great number of fungal infections are related to biofilm formation on inert or biological surfaces, which are recalcitrant to most treatments and cause human mortality. Cryptococcus laurentii has been diagnosed as the aetiological pathogen able to cause human infections mainly in immunosuppressed patients and the spectrum of clinical manifestations ranges from skin lesions to fungaemia. The effect of temperature, pH and surface preconditioning on C. laurentii biofilm formation was determined by 2, 3-bis (2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide (XTT) reduction assay. Scanning electron microscopic (SEM) analysis of C. laurentii biofilms demonstrated surface topographies of profuse growth and dense colonization with extensive polymeric substances around the cells. In this study, we determined the activity of amphotericin B, itraconazole and fluconazole against C. laurentii free-living cells and biofilms. The activity of antifungals tested was greater against free-living cells, but sessile cells fell into the resistant range for these antifungal agents. Extracellular polymeric substances (EPS), comprising the matrix of C. laurentii biofilms, were isolated by ultrasonication. Fourier transform infrared spectroscopy (FT-IR) was performed with ethanol-precipitated and dried samples. Also, the multielement analysis of the EPS was performed by inductively coupled plasma optical emission spectroscopy (ICP-OES).

Cryptococcus and Cryptococcosis in Cuba. A minireview

“…Although C. neoformans and C. gattii forms hyphae in the course of mating, these structures have not been observed in cryptococcal biofilms which consist of yeast cells that shed capsular polysaccharide which contributes to the ECM organisation. It has been demonstrated that this structure is more resistant than planktonic cells to oxidative stress suggesting that this phenotype increases resistance against host immune mechanisms and antifungal drugs, phenomena that could contribute to persistent infections …”

“…It has been demonstrated that this structure is more resistant than planktonic cells to oxidative stress suggesting that this phenotype increases resistance against host immune mechanisms and antifungal drugs, phenomena that could contribute to persistent infections. [50][51][52][53] Extrapulmonary dissemination, mainly to the CNS, is invariably associated with disease. The basis of C. neoformans/C.…”

Trichosporon inkin biofilms produce extracellular proteases and exhibit resistance to antifungals

“…Previous studies have shown that these conditions also enhance planktonic and biofilm growth of other fungal species (Ajesh & Sreejith, 2012;Di Bonaventura et al, 2006). T. inkin biofilms were formed in either low-glucose media (CLED, RPMI) or a nutrient-rich medium (Sabouraud) at both pH 7.0 and 5.5.…”

Non-Neoformans Cryptococcemia in a Patient With Hodgkin’s Lymphoma

“…Approximately 80% of non-neoformans cryptococcal infections are caused by C. laurentii and Cryptococcus albidus [4]. Most cases of nonneoformans cryptococcal fungemia are nosocomially acquired and the presence of invasive devices is a significant predisposing factor particularly when associated with C. laurentii infections [6]. Although in the present case, the patient did not have any indwelling medical device (e.g., central venous line), by having a hematological…”