Biofilm Formation by and Antifungal Susceptibility of Candida Isolates from Urine

Abstract

Biofilm formation (BF) in the setting of candiduria has not been well studied. We determined BF and MIC to antifungals in Candida spp. isolates grown from urine samples of patients and performed a retrospective chart review to examine the correlation with risk factors. A total of 67 Candida spp. isolates were grown from urine samples from 55 patients. The species distribution was C. albicans (54%), C. glabrata (36%), and C. tropicalis (10%). BF varied greatly among individual Candida isolates but was stable in sequential isolates during chronic infection. BF also depended on the growth medium and especially in C. albicans was significantly enhanced in artificial urine (AU) compared to RPMI medium. In nine of the C. albicans strains BF was 4-to 10-fold higher in AU, whereas in three of the C. albicans strains and two of the C. glabrata strains higher BF was measured in RPMI medium than in AU. Determination of the MICs showed that planktonic cells of all strains were susceptible to amphotericin B (AMB) and caspofungin (CASPO) and that three of the C. glabrata strains and two of the C. albicans strains were resistant to fluconazole (FLU). In contrast, all biofilm-associated adherent cells were resistant to CASPO and FLU. The biofilms of 14 strains (28%) were sensitive to AMB (MIC 50 of <1 g/ml). Correlation between degree of BF and MIC of AMB was not seen in RPMI grown biofilms but was present when grown in AU. A retrospective chart review demonstrated no correlation of known risk factors of candiduria with BF in AU or RPMI. We conclude that BF is a stable characteristic of Candida strains that varies greatly among clinical strains and is dependent on the growth medium. Resistance to AMB is associated with higher BF in AU, which may represent the more physiologic medium to test BF. Future studies should address whether in vitro BF can predict treatment failure in vivo.

Silicone colonization by non-Candida albicans Candida species in the presence of urine

“…However, it should be emphasized that only a few isolates were used and other isolates belonging to the same species may be able to form stronger biofilms. Furthermore, the authors verified that, as previously recognized (Jain et al, 2007;Uppuluri et al, 2009), an increase of sugars (which could be representative of diabetic patients) is a requirement for increased biofilm formation (data not shown). Furthermore, fungal infections are also more common in patients with diabetes, particularly those involving Candida species, occasionally causing dramatic clinical repercussions with obstruction of the urinary catheter (Patterson & Andriole, 1995).…”

“…It is known that mature Candida biofilms are organized into structured communities embedded within a matrix of extracellular material that is produced by the biofilm cells (Al-Fattani & Douglas, 2006;Silva et al, 2009). Formation of mature biofilms and consequent production of matrix is strongly dependent on environmental conditions, such as medium composition, pH, oxygen, species and strains (Jain et al, 2007;Ramage et al, 2006). In fact, these particular isolates are not capable of forming dense 3D biofilms and producing enough matrix (Fig.…”

“…The cell pellets were finally resuspended in artificial urine (AU) and cell concentration was adjusted using an improved Neubauer haemocytometer to 1610 7 cells ml 21 . AU (pH 5.8) was prepared with slight modification to that previously described (Shin et al, 2002;Jain et al, 2007). The composition of the AU used in this study was: CaCl 2 , 0.65 g l 21 ; MgCl 2 , 0.65 g l 21 ; NaCl, 4.6 g l 21 ; Na 2 SO 4 , 2.3 g l 21 ; Na 3 C 3 H 5 O(CO 2 ) 3 , 0.65 g l 21 ; Na 2 C 2 O 4 , 0.02 g l 21 ; KH 2 PO 4 , 2.8 g l 21 ; KCl, 1.6 g l 21 ; NH 4 Cl, 1.0 g l 21 ; urea, 25.0 g l 21 ; creatinine, 1.1 g l 21 ; and glucose, 0.3 %.…”

“…The cell pellets were finally resuspended in artificial urine (AU) and cell concentration was adjusted using an improved Neubauer haemocytometer to 1610 7 cells ml 21 . AU (pH 5.8) was prepared with slight modification to that previously described (Shin et al, 2002;Jain et al, 2007). Silicone.…”

The Oral Cavity: A Reservoir that Favors Colonization and Selection of Candida parapsilosis sensu stricto Strains with High Pathogen Potential Under Conditions of Gingival-periodontal Disease

“…With respect to this, we found that isolates derived from oral niches with GPD showed a significantly higher biofilm biomass compared to strains isolated in healthy oral conditions. This result was confirmed in two different culture media, RPMI 1640 and YPD, and agrees with reports by Hasan F. et al (2009) [54] and Jain N. et al (2007) [55], who also suggested that the origin and selection of isolates may be an influential factor in this Candida species biofilm formation. Furthermore, conversion of Candida species from commensalism to parasitism and their overgrowth are usually associated with changes in the intraoral environment such as unhygienic prostheses and xerostomia, or systemic factors such as type 2 diabetes (DM2) and immunodeficiencies.…”