[Morphological and biochemical features of fungi isolated from patients with renal failure]

Patients with renal failure are more frequently at risk of fungal infections than the healthy individuals. The aim of the study was: (1) Evaluation of the prevalence of fungi in biological materials obtained from different ontocenoses from patients with end-stage and chronic renal failure undergoing haemodialysis and conservative treatment, respectively. (2) Species determining of isolated fungal strains and evaluation their morphological and biochemical features with regard to biotyping. (3) Examining the connection between intraspecies features of fungal strains isolated from different ontocenoses of the same patient. The study group comprised 136 persons, including 56 patients with end-stage renal failure dialysed for the mean period of 36.2 (+/- 1.62) months--all patients were on chronic haemodialysis therapy (4 hours sessions, 3 times per week), 50 patients with chronic renal failure undergoing conservative treatment and 30 persons with the negative history of any renal disease--control group. At the moment of the evaluation and collection of samples all patients were in good condition, none of the patients revealed symptoms suggesting possible fungal infection. Material for mycological examinations included washings from the oral cavity and samples of urine and faeces. In order to evaluate morphological and biochemical features of fungi the following methods were applied: (1) macrocultures in solid Sabouraud medium, (2) direct microscopic slides, (3) API 20 C AUX test and (4) API ZYM test (bioMérieux). Totally 385 samples for mycological examinations were collected from different ontocenoses, from which 161 fungal strains were isolated and classified to 17 species from 5 genera. Most strains belonged to the genus Candida 96.9% and the most frequently occurring species was C. albicans (60.3%). Other species from this genus composed 39.7%, among which in 11.8% of cases C. parapsilosis was determined, and the following were: C. guilliermondii and C. humicola--both species isolated in 5.59%, C. glabrata (4.35%), C. rugosa and C. tropicalis (both species were isolated in 2.48%). The remaining isolated fungal strains (3.11 +/- 1.37%) belonged to genera Cryptococcus, Geotrichum, Saccharomyces and Trichosporon. The prevalence of fungi in collected biological materials from chronic dialysed patients, treated conservatively and persons from control group was determined at the level of 96.4%, 64.0% and 63.3%, respectively. In all examined groups fungi were found in high percentage in the ontocenoses of oral cavity and gastrointestinal tract; in dialysed patients (40.7%), treated conservatively (34.4%) and in persons with negative history of any renal disease (42.1%). It should be expressed that in 9.37% of patients with chronic renal failure undergoing conservative treatment fungi were determined at the same time in materials obtained from three ontocenoses--oral cavity, gastrointestinal tract and urinary tract. The majority of C. albicans strains (34.0%) was described by the use of code AUX 2 576 174; code 2 566 174 was found in 23.4% of species. Strains with code AUX 2 576 174 in 96,9% were isolated from chronic haemodialysed patients whereas code 2 566 174 characterized strains (68.2%) obtained from patients treated conservatively. Examined fungal strains from genus Candida obtained from all persons revealed the activity of 10 to 17 enzymes in the API ZYM test. Strains of genus Candida albicans obtained from patients with chronic renal failure treated conservatively and undergoing haemodialysis in majority belonged to biotype A (58.8%) and D3 (40.4%), respectively.