In-vitro Inhibition of Biofilm Formation in Candida albicans and Candida tropicalis by Heat Stable Compounds in Culture Filtrate of Aspergillus flavus

Potential and Prophylactic Use of Plants Containing Saponin-Type Compounds as Antibiofilm Agents against Respiratory Tract Infections

Epidemic diseases have been observed in every period of human history, and the treatment process has taken time. Causative microorganisms reproduce as biofilm and contribute to the emergence of various infectious diseases. The process that starts with respiratory disorders causes serious lung infections due to bacteria and viruses that accumulate and multiply. The biofilms are difficult to eliminate and show increased resistance to available antimicrobial agents. There is a need to identify and develop potential resources used in treatment. The search for novel biological agents from plants is gaining popularity due to the high abundance, accessibility with consequent lower cost for discovery, and lesser side effects and toxicity. Saponins found in some plants can be alternative to antibiotics, with antimicrobial activities. This review focused on the potency of saponin-containing plants with antimicrobial properties as antibiofilm agents against these infections. For this purpose, keywords were scanned in Web of Science, Scopus, and Google academics databases, and the related literature was compiled. Approximately, 25 plant taxa belonging to 18 families traditionally used in the treatment of respiratory diseases are listed. These taxa mostly belong to Fabaceae, Asteraceae, Apiaceae, and Asparagaceae families, respectively. Most of these taxa have antibacterial, antifungal, antitussive, and anti-inflammatory activities. Especially, plants with antibiofilm activity that can be effective against many microorganisms are compiled in this study. These plants can prevent or treat upper respiratory tract diseases caused by bacteria due to the phytochemicals they contain, especially saponins.

Susceptibility of Candida albicans Isolated from Blood to Wickerhamomyces anomalous Mycocins

The occurrence of infections caused by Candida albicans in developed and developing countries and their resistance to some available antifungal drugs have been viewed as causing a great problem to human health worldwide. In order to find new researched molecules, there are some mycoses secreted by yeasts, especially mycocins produced by Wickerhamomyces anomalus with a broad antimicrobial spectrum of activity. Thus, this trial aimed at evaluating mycocins' activity obtained from environmental W. anomalus cell wall compared to thirty C. albicans strains isolated from blood. Mycocins were extracted from cell walls of three W. anomalus strains (WA40, WA45, and WA92). The 400 μg mL^-1 concentration of WA40M1, WA45M2, and WA92M3 mycocin extracts showed the following respective activity results: 96.6, 96.6, and 90.0 % C. albicans strains. WA45M2 and WA92M3 mycocin extracts showed some activity in 3.3 % of C. albicans strains at 50 μg mL^-1 concentration. Mycocins extracted from cell walls of three W. anomalus strains named as WA40, WA45, and WA92 showed antifungal activity compared to C. albicans and low degree of hemolysis.

Inhibition of biofilm formation and lipase in Candida albicans by culture filtrate of Staphylococcus epidermidis in vitro

Background:

Candida spp. are fourth most common cause of bloodstream infection in developed countries and emerging agents of fungemia in developing countries, with considerable attributable mortality. Candidemia is associated with the formation of complex, structured microbial communities called biofilms. Biofilm formation makes treatment difficult due to improper drug penetration and factors like high cost and adverse effects of antifungal drugs available. Hence, low-cost alternatives are urgently required to treat device-associated invasive candidiasis.

Objectives:

To study the effect of culture filtrate of Staphylococcus epidermidis on biofilm formation and lipase expression of Candida albicans in vitro.

Materials and Methods:

Yeast cells isolated from clinical samples were suspended to a turbidity of 10⁶ in (a) Yeast extract-peptone-dextrose (YPD) broth and (b) culture filtrate, and 100 μl of each were dispensed in separate wells of microtiter plate. After repeated washing and reloading with respective liquid media, readings were taken spectrophotometrically. To check for lipase inhibition, yeasts were incubated overnight in YPD and filtrate and subcultured on media containing Tween-80 and CaCl₂. Positive lipase activity was denoted by haziness around colonies.

Results:

Mean reading of C. albicans in YPD broth was 0.579 while the same when yeasts were suspended in S. epidermidis culture filtrate was 0.281 (P < 0.05 by Z-test of significance). Lipase of C. albicans was inhibited by culture filtrate. Filtrate was found to be nontoxic to human cell line.

Conclusions:

Culture filtrate of S. epidermidis can hence pave the way for development of new strategies to inhibit biofilm formation in device-associated candidemia.

Bioactivity of a family of chiral nonracemic aminobenzylnaphthols towards Candida albicans

Chiral nonracemic aminobenzylnaphthols were obtained by a Betti multi-component reaction between 2-naphthol, aryl aldehydes and enantiopure arylethylamine. Moreover, some new aminobenzylnaphthols were synthesized by a similar reaction between 2-naphthol, aryl aldehydes and prolinol. These aminobenzylnaphthols, synthesized from different components and thus having different structural features, were tested as anti-yeast agents inhibiting Candida albicans. The effect towards the test strain was studied with a microdilution approach and three different concentrations (150, 300 and 450 µg/mL) were tested. The best results were found for the aminobenzylnaphthols obtained from 1-naphthylethylamine and from natural prolinol. The use of the two-way ANOVA highlighted the better performances of the prolinol derivative among the differently structured aminobenzylnaphthols that were screened. The activity towards C. albicans of this prolinol derivative resulted to be interesting and could represent a promising alternative to overcome the problem of the strains resistant to the traditional antifungals.