Introduction: Candida auris is an emerging multidrug-resistant fungal pathogen responsible for severe invasive infections with high mortality rates. First identified in 2009, C. auris has rapidly spread worldwide and is now considered an urgent threat by the CDC [1]. A distinguishing feature of C. auris is its unique cell wall composition, particularly the outer mannan layer, which is crucial for immune evasion, host cell adhesion, and biofilm formation. However, the structure and biosynthesis of C. auris mannan remain poorly understood compared to the well-studied mannan of Candida albicans [2].

The growth and morphology of C. auris are significantly influenced by culture conditions such as temperature, salt concentration, and media composition. Optimal growth occurs at 37-40°C, and high salt concentrations induce pseudohyphal-like forms [3]. Understanding the impact of environmental factors on C. auris morphology is essential for comprehending its pathogenicity [2].

Aim: This study aims to investigate and compare the impact of cultivation conditions (media, temperature, and pH) on the structure and composition of Candida auris cell wall mannan, and to characterize its features in comparison with those of other Candida species.

Methods: The cultivation conditions for C. auris were adopted from other Candida species to study their effects on cell morphology and isolated mannan. Various media, including Sabouraud Dextrose Agar (SDA), Yeast Nitrogen Base (YNB), Yeast Extract-Peptone-Dextrose (YPD), and Synthetic Liquid Medium (SLM), were used. Temperatures ranged from 25°C to 42°C, with a focus on mimicking human body temperature at 37°C.

Cultivation Media and Conditions:

1. Sabouraud Dextrose Agar (SDA): Used for general cultivation.
2. Yeast Nitrogen Base (YNB): A defined medium lacking a carbon source; glucose or galactose can be added. The choice of carbon source influences mannan structure [2].
3. YPD Medium: Commonly used for yeast cultivation; conditions include 37°C for typical growth, with high salt concentrations inducing pseudohyphal-like forms [4].
4. Synthetic Liquid Medium (SLM): Used for comparison studies with Candida albicans, with cultivation at 37°C under static and shaking conditions [5].

Results and Discussion: The study observed that cultivation conditions, including media composition and temperature, profoundly influence C. auris morphology. For instance, YPD medium with high NaCl concentrations induced pseudohyphal-like growth [6]. In contrast, SLM at 37°C showed smooth, small colonies without pseudohyphae [5]. Passage through a mammalian host was found to induce a phenotypic switch between yeast and filamentous forms, influenced by temperature [7].

The mannan structure of C. auris, particularly its enrichment in β-1,2-Man-linkages, enhances binding to IgG and mannose-binding lectin, aiding in immune evasion. This structural characteristic underscores the importance of studying how different cultivation conditions affect mannan composition [8].

Conclusion: This review highlights the significant impact of cultivation conditions on C. auris morphology and mannan structure. While the current study provides insights, further research is necessary to fully understand the mannans of C. auris isolated under various cultivation conditions. This understanding is crucial for developing targeted interventions against this multidrug-resistant pathogen.