An in vitro study of interactions of Candida albicans with Klebsiella pneumoniae and Enterococcus faecalis isolated from intestinal microbiome of HIV infected patients

Abstract

The aim: In vitro identification of targets for antagonism factors in klebsiellas and enterococci for Candida albicans isolated from the intestinal microbiome of HIV infected patients.Materials and methods. The tests were performed using 38 Candida albicans strains, 28 Klebsiella pneumoniae strains, and 30 Enterococcus faecalis strains isolated from the intestinal microbiome of 89 HIV infected children. The mean age of the patients was 24 ± 2 months; the group consisted of 49 (55%) boys and 40 (45%) girls. Microorganisms were isolated from the intestinal biotope using such selective media as HiChrome Candida Agar, HiChrome Klebsiella Selective Agar Base, and Enterococcus Agar; the study included identification of species. Model experiments were performed to study anti-catalase activity of E. faecalis exometabolites and the impact of K. pneumoniae on morphological transformation of C. albicans fungi.Results. Klebsiellas decrease the intensity of germ tube formation in C. albicans by 58.7% (p 0.01). When cocultured, 12.3% of the yeast cells produce germ tubes, while 29.8% of transformed cells was detected in the fungal monoculture. It has been found that exometabolites of 65.7% of E. faecalis strains decrease production of catalase in C. albicans. The initial catalase level in untreated cultures of C. albicans averages 1.02 µmol/min of optical density; after they are treated with E. faecalis exometabolites, the level decreases to 0.55 µmol/min, i.e. by 46.1% (p 0.05).Conclusions. K. pneumoniae and E. faecalis demonstrate antagonism of different intensity toward C. albicans. Morphological transformation and catalase production are targets for antagonism factors of facultative microbiota in C. albicans.