The effects of secreted aspartyl proteinase inhibitor ritonavir on azoles‐resistant strains of Candida albicans as well as regulatory role of SAP2 and ERG11

Abstract

Background Candida albicans, the main human fungal pathogen, can cause fungal infection and seriously affect people's health and life. This study aimed to investigate the effects of ritonavir (RIT) on C. albicans and the correlation between SAP2 as well as ERG11 and drug resistance. Results Secreted aspartyl proteinases (Saps) activities and pathogenicity of C. albicans with different drug resistance were measured. M27‐A4 broth microdilution method was used to analyze the drug sensitivity of RIT combined with fluconazole (FCA) on C. albicans. After that, SAP2 and ERG11 mutations were examined by polymerase chain reaction (PCR) and sequencing, and quantitative real‐time PCR was utilized to determine the expression of the two genes. By analyzing pz values, the Saps activity of cross‐resistant strains was the highest, followed by voriconazole (VRC)‐resistant strains, FCA‐resistant strains, itraconazole (ITR)‐resistant strains, and sensitive strains. The pathogenicity of C. albicans in descending order was as follows: cross‐resistant strains, VRC‐resistant strains, ITR‐resistant strains, FCA‐resistant strains, and sensitive strains. With the increase of RIT concentrations, the Saps activity was gradually inhibited. Drug sensitivity results showed that there was no synergistic effect between RIT and FCA. Additionally, no gene mutation sites were found in SAP2 sequencing, and 17 synonymous mutations and 6 missense mutations occurred in ERG11 sequencing. Finally, the expression of SAP2 and ERG11 was significantly higher in the resistant strains compared with the sensitive strains, and there was a positive liner correlation between SAP2 and ERG11 messenger RNA expression (r = .6655, p < .001). Conclusion These findings may help to improve our understanding of azole‐resistant mechanisms of C. albicans and provide a novel direction for clinical therapeutics of C. albicans infection.

Detection of ERG11 gene in fluconazole resistant urinary candida isolates

“…However, upon the addition of fluconazole, both groups showed increased Erg11 expression. 72 There were statistically significant difference concerning the association of proteinase activities and Erg 11 gene expression among fluconazole resistance Candida isolates. This was in accordance with Feng et al, 2021 72 who reported that the expression of secreted aspartyl proteinase 2 (SAP2) and ERG11 was significantly higher in the resistant strains compared with the sensitive strains, and there was a positive liner correlation between SAP2 and ERG11 messenger RNA expression.…”

Genomic Variation-Mediating Fluconazole Resistance in Yeast

“…Genetic mutations are also associated with cross-resistance. For example, C. albicans isolates containing the A516P mutation in ERG11 exhibit an upregulated ERG11 expression and a notable cross-resistance to fluconazole, itraconazole, and voriconazole [ 12 ].…”

Comparative Analysis of Epidemiological and Clinical Characteristics Between Invasive Candida Infection versus Colonization in Critically Ill Patients in a Tertiary Hospital in Anhui, China

“…All the primers used in the present study are listed in Table 1 and had been commercially synthesized (Shanghai Sangon Biotech). [20][21][22][23] Yeast-DNA materials were carefully extracted as PCR templates with UNIQ-10 Column Yeast Plasmid Preps Kit (Shanghai Sangon Biotech), and PCR amplifications were conducted with an Applied Biosystems 7500 DNA analyzer (Thermo Fisher Scientific). The PCR parameters included 5 minutes at 94°C for initial denaturation, 32 cycles (30 s at 94°C for denaturation, 90 s at 50°C for annealing, and 90 s at 72°C for elongation), and 10 minutes at 72°C for last elongation.…”