In vivo and in vitro Pathogenesis and Virulence Factors of Candida albicans Strains Isolated from Cutaneous Candidiasis

Effect of the Sho1 gene on the pathogenicity of Candida albicans and immune function in vivo

Objectives

Sho1, a ubiquitous membrane protein in fungi, plays a pivotal role in various physiological processes, such as osmotic stress, oxidative stress, temperature response, and virulence regulation across different fungal species. This study aimed to investigate the effect of the Sho1 gene on the pathogenicity of Candida albicans and its immune function in vivo.

Materials and methods

Ninety-nine clinical strains from various infection sites were collected to investigate the expression levels of the Sho1 gene compared to its levels in the standard strain (SC5314). Sho1-knockout strains (Sho1Δ/Δ) were constructed to investigate the impact of the Sho1 gene deletion on the biofilm formation, adhesion, and flocculation abilities of C. albicans. A mouse model of systemic infection was established to evaluate the impact of Sho1 deletion on survival, organ pathology, and immune cell function, as assessed by flow cytometry.

Results

The expression level of the Sho1 gene was found to be higher in clinical strains derived from sterile fluids, sputum, and secretions compared to that in the standard strains. Deletion of the Sho1 gene diminished the biofilm-formation capacity of C. albicans, leading to a sparse structure and reduced thickness, as well as diminished adhesion and flocculation abilities. Deletion of the Sho1 gene prolonged mouse survival; decreased the fungal load in the liver, kidney, and spleen; and reduced inflammatory cell infiltration into the kidney. In the spleens of mice injected with the Sho1Δ/Δ strain, a decrease was observed in the percentage of M1-type macrophages and an increase in M2-type macrophages, resulting in a decreased M1/M2 macrophage ratio. Additionally, an increase was observed in the number of Th1 cells and a decrease in the number of Th2 and Th17 cells, leading to an increased Th1/Th2 ratio.

Conclusion

The Sho1 gene significantly contributes to the pathogenesis of C. albicans by influencing its biological behaviour and immune response in vivo.

Isolation and Identification of Candida tropicalis as a Cause of Cutaneous Candidiasis in Kalar District, Iraq

Fungal infections are currently causing health issues all over the world, among which are Candida species that cause cutaneous infection. Numerous dermatological studies concentrated on a single species. However, the virulence factors and the spread of specific candidiasis in specific areas have remained poorly understood. Therefore, the current study was designed to shed light on Candida tropicalis, which has been identified as the most prevalent yeast among Candida non-albicans species. Forty specimens were collected from patients with cutaneous fungal infection (25 females and 15 males) and underwent examination. According to conventional identification based on macroscopic and microscopic examinations, eight isolates were identified as C. tropicalis from Candida non-albicans. Molecular diagnosis for internal transcribed spacers (ITS1 and ITS4) using conventional polymerase chain reaction (PCR) yielded an amplicon of 520 bp for all isolates. Further investigation of PCR-restriction fragment length using Mitochondrial sorting protein; Msp1 enzyme revealed two bands of 340 and 180 bp. The ITS gene sequence in one isolated species was found to be 98% identical to C. tropicalis strain MYA-3404 chromosome R ATCC CP047875.1. Another isolate shared 98.02% identity with C. tropicalis strain MA6 18S ribosomal RNA gene DQ666188.1, indicating C. tropical species identity, implying that non-Candida species should be considered when diagnosing candidiasis. This study demonstrated the significance of Candida non-albicans, particularly C. tropicalis, in terms of pathogenic potential, the ability to cause potentially fatal systemic infections and candidiasis, and acquired flucozonal resistance with a high mortality rate.

Effect of Carum carvi essential oil on ERG6 gene expression and virulence factors in Candida albicans

Background and Purpose:

The present study was conducted to investigate the inhibitory effects of Carum carvi essential oil (EO) against ERG6 gene expression in relation to fungal growth and some important virulence factors in Candida albicans.

Materials and Methods:

The minimum inhibitory concentration (MIC) of C. carvi EO against C. albicans was determined by the Clinical and Laboratory Standards Institute M27-A4 method at a concentration range of 20-1280 μg/ml. Furthermore, the expression of ERG6 gene was studied at the 0.5× MIC concentration of C. carvi EO using real-time polymerase chain reaction. The proteinase and phospholipase activities, cell surface hydrophobicity (CSH), and cell membrane ergosterol (CME) content of C. albicans were also assessed at the 0.5× MIC concentration of the plant EO using the approved methods. In addition, fluconazole (FLC) was used as a control antifungal drug.

Results:

The results indicated that the MIC and minimum fungicidal concentration of C. carvi EO for C. albicans growth were 320 and 640 μg/ml, respectively. The expression of fungal ERG6 at an mRNA level and ergosterol content of yeast cells were significantly decreased by both C. carvi EO (640 μg/ml) and FLC (2 μg/ml). The proteinase and phospholipase activities were also reduced in C. carvi EO by 49.82% and 53.26%, respectively, while they were inhibited in FLC-treated cultures by 27.72% and 34.67%, respectively. Furthermore, the CSH was inhibited in EO- and FLC-treated cultures by 12.75% and 20.80%, respectively.

Conclusion:

Our findings revealed that C. carvi EO can be considered a potential natural compound in the development of an efficient antifungal agent against C. albicans.